[HN Gopher] FCC Temporary Waiver Permits Higher Symbol Rate Data...
       ___________________________________________________________________
        
       FCC Temporary Waiver Permits Higher Symbol Rate Data for Hurricane
       Ida Traffic
        
       Author : 7402
       Score  : 162 points
       Date   : 2021-08-30 15:31 UTC (7 hours ago)
        
 (HTM) web link (www.arrl.org)
 (TXT) w3m dump (www.arrl.org)
        
       | spookthesunset wrote:
       | They should figure out how to rework the regulations to limit
       | bandwidth, not baud. The intent is to keep a few amateur radio
       | operators from hogging a ton of the very limited HF spectrum. If
       | somebody can figure out how to cram more data into a small slice
       | of bandwidth, more power to them.
        
         | p_j_w wrote:
         | It's been discussed. From the article:
         | 
         | "In 2016, in response to an ARRL petition for rulemaking, the
         | FCC proposed to remove the symbol rate limitations, which it
         | tentatively concluded had become unnecessary due to advances in
         | modulation techniques and no longer served a useful purpose.
         | That proceeding, WT Docket 16-239, is still pending."
        
         | lima wrote:
         | That's how it works in most of Europe (for the most part) -
         | there's limits on duty cycle, bandwidth and power.
        
         | edrxty wrote:
         | I've had a number of "cordial debates" with crusty old hams on
         | this subject. The old guard is still very much hung up on the
         | Old Way. Change scares a lot of the people who learned on
         | expensive vaccum tube systems before the hobby was more broadly
         | accessible. Things like high baudrate, bandwidth negotiation,
         | spread spectrum and encryption scare the pants off of them
         | regardless of the fact that the bands are mostly empty.
        
           | fortran77 wrote:
           | It's disgusting how hacker news allows attacks on people
           | because of their age.
        
             | edrxty wrote:
             | Apologies, I was trying to point at a mentality rather than
             | an age but obviously the wording could be better. There are
             | plenty of 20-30 somethings that hold the same beliefs and
             | plenty of older ones that agree with me. The amateur radio
             | community is a rather complicated landscape and that bears
             | acknowledging.
        
           | VLM wrote:
           | "bandwidth negotiation" - HF paths are often unidirectional
           | in the sense that you can interfere with station A without
           | station B being able to hear. You can easily interfere with
           | people you can't hear and autonegotiation mean you're
           | autojamming without being aware of it. Not an issue with
           | "human in the loop" modes. No application layer need for it
           | anyway.
           | 
           | "spread spectrum" - See above, plus raising the noise floor
           | means the death of entire weak signal modes.
           | 
           | "encryption" - Absolutely no need. Would be death of ham
           | radio. Why bother with cheap ham radio licenses if you can
           | just transmit anything you want but encrypted.
           | 
           | "the bands are mostly empty" Buy a better antenna LOL.
        
             | edrxty wrote:
             | Found one
             | 
             | Bandwidth negotiation - you can already interfere in the
             | same way without it. This is also true of any radio
             | communication, ELF or EHF
             | 
             | Spread spectrum - yes but has the ability to not
             | significantly interfere with any single other link, can
             | obviously otherwise be kept out of the tiny segment for
             | weak digital or otherwise confined to sub bands
             | 
             | Encryption - this one's my favorite: the hardware is
             | already common, if this argument were true then ham would
             | already be dead. If someone is being abusive they don't
             | give their call anyway and we hunt them with DF the way we
             | always have.
             | 
             | Bands - have you seen 17m to light?
             | 
             | Tldr we have coexisted by being neighborly for over 100
             | years. New technologies won't add or remove the underlying
             | need for being neighborly. We can therefore play with the
             | new toys if we continue to uphold those principles as we
             | always have.
        
               | op00to wrote:
               | I tuned into 12m randomly for about 10 minutes around
               | lunch time today and picked up a /mm calling CQ which was
               | fun.
        
               | VLM wrote:
               | Bandwidth negotiation - Uh, no. Human in the loop with
               | ears can hear a complaint of interference and stop or
               | adjust. Autonegotiation just turns up the power until the
               | victim can't use the service anymore. RF is not a phone
               | line. Note that we have legal things like RSID mode
               | detection, which is not autonegotiation. Autonegotiation
               | is a great technology for military anti-jamming purposes,
               | not ham radio.
               | 
               | Spread spectrum - The coding gain from SS varies with the
               | bandwidth spread across, so SS over a narrow enough
               | channel... isn't even SS anymore. That said we seem to
               | agree that VHF and up there's plenty of space to
               | channelize and regulate by frequency. What does anyone
               | gain from it other than it interferes with anything else
               | in its channel?
               | 
               | Encryption - You haven't explained why its needed. "I
               | can't talk to you, you can't talk to me" isn't very
               | neighborly or ham radio friendly. So its not needed and
               | only provides downsides. Emcom is difficult enough
               | without everyone not sharing secret keys. What part 97.1
               | "basis and purpose" section does secretive private
               | transmissions benefit? I mean, if it was useful for some
               | ham radio purpose, sure sounds cool go for it. Encryption
               | is certainly very useful for non-ham-radio purposes, but
               | then by definition it shouldn't be on the ham bands
               | anyway. I admit there are weird exceptions where
               | encryption might be useful, which are already written
               | into regulation, like 97.211 "Space telecommand station"
               | part (b) permits space satellite control uplinks to be
               | encrypted, but only the control signals, which makes
               | sense, so some rando doesn't take over a satellite...
               | 
               | "New technologies won't add or remove the underlying need
               | for being neighborly."
               | 
               | Agreed. As of 2021 nobody has invented a technology for
               | wideband digital to coexist with, well, anything, other
               | than regulating under a channelized system, which seems
               | impossible for international HF.
               | 
               | Your three main arguments seem to boil down to "why can't
               | I jam other people?" whereas my point of view is "why
               | would anyone want to jam other people" so we're probably
               | never going to get along.
        
               | a-dub wrote:
               | as someone who is not familiar with this world (but takes
               | deep interest in (n)etiquette), would someone be willing
               | to do a quick breakdown of ham netiquette, "being
               | neighborly", fears of encryption and how abuse is managed
               | in the ham world?
               | 
               | i ask because maybe there are some learnings and lessons
               | there that could apply to internet policy today.
               | 
               | it sounds like certain things, like anonymity, are
               | banned? there's some sort of community policing? i'm
               | super curious.
        
               | VLM wrote:
               | Yeah there's no anonymity.
               | 
               | As for community policing the FCC itself polices some,
               | and the official observer program has been replaced by
               | the volunteer monitor program which is mostly the same
               | thing.
               | 
               | I think you can assume much like on the net, there's at
               | least ten times as many lurkers listening as there are
               | people talking.
               | 
               | Back in '28, 1928, the radio amateur's code was written
               | which was a pretty good attempt at letting people talk as
               | much as possible while eliminating ore reducing flame
               | wars over the air.
               | 
               | https://www.arrl.org/amateur-code
               | 
               | This mentions the informal, sometimes ignored, ban on
               | political speech:
               | 
               | https://en.wikipedia.org/wiki/History_of_amateur_radio
               | 
               | My guess is over the last century the more authoritarian
               | govts banned it, and the free-er countries have lots of
               | people who like to collect contacts and you're not going
               | to get a collectible QSL card in the mail from a guy if
               | over the air you call him a filthy (insert appropriate
               | political slur here) so naturally people tended to not
               | talk about politics, because gotta collect QSL cards or
               | contest points or whatever.
               | 
               | On the radio, the quality of your station and antenna and
               | your skills determine how many people you can talk to, so
               | competition, so people are more civil to each other. On
               | the internet, unfortunately everyone "hears" everyone, so
               | there's no gain from not being a jerk, so there's lots of
               | jerks.
        
               | jtdressel wrote:
               | I don't have a lot of time, but this was an interesting
               | question. If you message me I'll dig up references. There
               | are nuances and exceptions to almost everything I list
               | below.
               | 
               | The radio spectrum is a scarce resource. Two of the main
               | reasons amateur radio users are given access to the
               | spectrum is to help with disaster recovery and to advance
               | the art and science of radio.
               | 
               | Callsigns are public - you can look up anyone's to see
               | who they are.
               | 
               | You're required to give your callsign at the end of your
               | transmission, and every 10 minutes.
               | 
               | There are some limitations on content. No music, no
               | profanity, no commercial uses, and no encryption.
               | 
               | netiquette varies based on what you are doing. In
               | general, shorter range bands have better sound quality
               | and are more casual. Longer range has worse sound quality
               | (or no sound like morse or ft8).
               | 
               | If you're on one of the shorter range bands (e.g. 70cm)
               | you'll often find people who are keeping in touch with
               | friends, or just looking for someone to talk to.
               | 
               | On the longer range, you'll run into stuff like contests
               | - all the other person wants to know is who you are, and
               | where you are. They're trying to see either how many
               | contacts they can make in a period of time or how far
               | away they're able to make contacts.
               | 
               | There are "formal traffic" nets - which pass messages.
               | Local nets will route traffic they can't deliver to
               | regional nets, and then back down to local nets. Usually
               | they just pass practice traffic around - until a disaster
               | occurs and they are needed. More info
               | https://www.arrl.org/nts-manual
               | 
               | The lowest level license is the Technician. You can find
               | the Technician exam pool online in several formats. https
               | ://www.arrl.org/files/file/VEs/2018-2022%20Tech%20Class..
               | .
               | 
               | Edit: I forgot about you abuse question. Hams tend to
               | police their own or will work with the FCC to report
               | people misusing the airwaves. The practice version of
               | this is called "fox hunting" - where someone places a
               | transmitter and you try to find it.
               | 
               | Most hams care about keeping the hobby alive. If they
               | find someone who's broadcasting with too much power or
               | without a license usually they'll try to work with that
               | person to correct the behavior. If that doesn't work,
               | they'll often work with the FCC.
        
               | swalberg wrote:
               | Only been a Ham for 2 years, but the etiquette I've
               | observed falls along the lines of "don't do things that
               | make it hard for other people to have fun". Like checking
               | to see if the frequency is in use before sending, and not
               | blasting out a wide signal when a narrow one will do.
               | Respecting band plans, both formal and informal,
               | especially digital people sticking around established
               | watering holes and not splattering the CW areas. Don't
               | tune up (sending a tone to configure your antenna tuner)
               | on someone's frequency.
               | 
               | Another part is "let people do their thing". Like if
               | someone's in a special activity and managing a pileup
               | (lots of people trying to call), just give them the
               | exchange and move on.
               | 
               | Due to the asymmetric nature of propagation, stuff
               | happens. You may not hear anyone using the frequency but
               | they hear you just fine. If band conditions take a turn
               | for the worse, politely tell the other person you're
               | losing them and thanks for the conversation.
               | 
               | Anonymity is banned; FCC part 97 says you have to use
               | your call sign every 10 minutes and at the end of the
               | transmission.
               | 
               | Ultimately the FCC is responsible for enforcing these but
               | of course don't have the time. People can report people
               | to the FCC and they _may_ open an investigation depending
               | on that nature of it. There's also the ARRL volunteer
               | monitoring program where participants listen on the air
               | and, through the program, send out notices of good and
               | bad behavior, optionally referring cases to the FCC. It's
               | usually stuff like "guy constantly being a jackass on a
               | repeater and ruining it for others", with a good bit of
               | "sending outside your privileges" and "not identifying
               | yourself".
               | 
               | That said we've all accidentally sent outside our
               | privileges, we've all stepped on people. It happens.
               | 
               | As amateurs we know that if we don't do a good job of
               | operating we'll lose the spectrum, so it's usually not a
               | huge problem. There are jerks, there are also people that
               | don't know they're being jerks.
        
               | kragen wrote:
               | There's very little emergency communication that wouldn't
               | benefit from at least cryptographic signatures; in many
               | cases it's also important to be able to communicate
               | private data in emergencies. Not allowing encryption
               | makes amateur radio of very little use in emergencies.
               | 
               | There are lots of "telecommand" use cases that aren't to
               | satellites, too.
               | 
               | The broader problem is that prohibiting new technologies
               | in ham radio until they've been demonstrated to be useful
               | (in your case, demonstrated to be useful _in ham radio_ ,
               | despite being prohibited at the time, but most people are
               | less blatantly unreasonable) is a recipe for, at best,
               | chasing the taillights of commercial radio systems, and
               | more commonly total technological stagnation and gradual
               | abandonment.
        
               | VLM wrote:
               | > Not allowing encryption makes amateur radio of very
               | little use in emergencies.
               | 
               | I can't even imagine what would require encryption ...
               | maybe PII medical traffic under some peculiar artificial
               | scenario and most pessimistic possible HIPPA
               | interpretation?
               | 
               | Now remember, that the stereotype of ham radio emcom is
               | people roll up with no idea how to program their HT to
               | the correct frequencies so they can't even participate.
               | So demanding everyone participate in a GPG WoT or join a
               | Kerberos domain to share encryption keys is an absolute
               | non-starter. If the general public cannot participate
               | without extensive preparation before the event, it means
               | its not part 97 emcom, its just a poor low budget
               | imitation of part 90, its not part 97 operation at all.
               | Why not get GMRS licenses?
               | 
               | Remember there is the perpetual battle in emcom between
               | the people who think "provide emergency communications"
               | applies to Big Brother despite his infinite budget
               | outclassing any possible Ham response, vs the people who
               | think emergency communications is for the people or the
               | general public or even for the individual. Both sides
               | like to denigrate the other side, unfortunately.
               | 
               | So consider I was listening to a rando ham "involuntary
               | storm chaser" report a tornado sighting to the NWS a
               | couple weeks ago. How, in that scenario does encryption
               | help? By making it impossible for the ham to talk to the
               | NWS station because they never shared keys in advance or
               | they shared the 2020 keys and not the 2021 keys? By
               | making it impossible for the general public to hear the
               | tornado report they would be safer not knowing?
               | 
               | Consider something topical, like the hurricane in NO. A
               | rando member of the general ham radio public reports
               | hurricane related flooding. The value encryption provides
               | is making it impossible for the ham radio operator to
               | talk to people to make the report, and encryption also
               | makes it impossible for the general ham radio public to
               | help. "Real ham radio emcom" situation he'd just dial up
               | the repeater and talk to net control and make his report
               | and move on with life. Somehow encryption would help, but
               | ... how?
               | 
               | Edited to add:
               | 
               | > There are lots of "telecommand" use cases that aren't
               | to satellites, too.
               | 
               | I forgot to agree with you on that. Repeater control
               | links and the like.
        
               | kragen wrote:
               | Maybe "very little use in emergencies" was an
               | overstatement on my part. Clearly there is some important
               | communication in emergencies that doesn't need crypto.
               | 
               | But I think the vast bulk of communications necessary in
               | an emergency is between people who need to talk to their
               | family members to find out where they are, what condition
               | they're in, and what resources they have. That
               | information often needs to remain private between the
               | people who are communicating. Right now it's not mostly
               | sent over ham radio because it can't be. In fact, it
               | isn't transmitted at all, so people die. Advances like
               | Codec 2 dramatically expand our possibilities for
               | communications in emergencies, but mostly for doing new
               | things like that, things we're not already doing.
               | 
               | As another example, suppose that, instead of one person
               | reporting hurricane-related flooding you had a water-
               | level sensor every 100 meters in a rough hexagonal grid,
               | each transmitting a packet every 6 minutes carrying a
               | 16-bit ID and an 8-bit water level. In theory this is an
               | average of about 8 bits per second per square kilometer,
               | so it wouldn't have to cause much interference or use
               | much average power, but it's hard to get it to work under
               | Part 15 rules because Part 15 doesn't allow you to
               | average your power usage over 6 minutes, so you pretty
               | much have to build a mesh network to get adequate range
               | at the allowed power levels. You probably need to
               | cryptographically sign the packets for the system to be
               | reasonably reliable. (They don't need to be secret, but
               | you need to be able to distinguish legitimate reports
               | from griefers trying to divert emergency resources when
               | there's no emergency.)
               | 
               | Nowadays you might be able to do that with LoRa. But you
               | could have done it 20 years ago on the amateur bands ---
               | except that it's illegal. So again hams are chasing the
               | taillights of commercial radio, the opposite of how it's
               | supposed to be.
        
               | penagwin wrote:
               | I've listened to several police radios with my SDR - "old
               | male with [medical condition] at [person's address]"
               | isn't uncommon.
               | 
               | Some research - paramedics are likely covered under HIPAA
               | (if they work for a healthcare entity that provides
               | ambulance services), I don't believe police or the fire
               | department would be covered.
        
               | kragen wrote:
               | The things I'm thinking most need to be protected are
               | more like "unaccompanied 16-year-old girl [name] at
               | [station's address] plans to cross the recently burned
               | area to rendezvous with [family member's name] at
               | [rendezvous point]. She was able to get the cash savings
               | out of the safe before the house burned."
               | 
               | After Katrina, dead bodies with gunshot wounds rotted in
               | the streets for weeks, uninvestigated. Human jackals
               | aren't common but when they sense impunity they do make
               | their presence known.
        
               | krofptN wrote:
               | While I tend to agree more with your answers than edrxty
               | baseless claims about spread spectrum and unrealistic
               | bandwidth negotiation (doesn't work with hidden nodes),
               | it's important to note that there _are_ alternative
               | models to the ham spectrum management model. Namely:
               | 
               | ISM short range device (SRD) - the rules are very simple:
               | transmit anything you want, no more than xxx watts, tx
               | duty cycle no more than 1%. IMHO, this can be scaled to
               | ham frequencies (ex: 0.01% duty cycle).
               | 
               | ISM 2.4 GHz - the rules are (basically) transmit only if
               | no other signal is detected above threshold (-75dBm).
               | Exponential back off otherwise. This is also called the
               | Aloha model. This model also works most of the time,
               | although its applicability to HF propagation is unclear.
        
               | VLM wrote:
               | > This is also called the Aloha model
               | 
               | The history of HF packet radio going back almost 40 years
               | now, shows it stomps things pretty bad. RTTY and PSK31
               | ops simply cannot operate nearby HF packet channels.
               | 
               | Aloha DOES work really well for decades on "toll quality
               | VHF FM" strong high SNR local packet radio LANs.
               | 
               | Everyone's gotta be able to hear everyone or else channel
               | thruput drops to about zero. Easy on a city wide VHF FM
               | packet lan, impossible on HF.
               | 
               | Reminds me of thin net ethernet in the 80s (thicknet
               | also, LOL). One babbling transmitter and the whole LAN is
               | down for everyone.
        
               | edrxty wrote:
               | I feel like you're taking an extremely narrow view of use
               | cases, but I apologize I'm coming off as antagonistic,
               | it's not my intent. I really just want people to open up
               | to expanding what's possible in our bands.
               | 
               | The ham bands are for experimentation. Currently
               | experimentation is essentially banned as the most of the
               | biggest recent innovations are against the rules and the
               | old guard wants to ban the rest (see FT8/WSPR).
               | 
               | Negotiation - there are plenty of bandwidth negotiation
               | strategies, not just scream louder. You can listen and
               | avoid areas where people are obviously talking, it
               | doesn't take human level intellect to detect signal.
               | 
               | SS - interference avoidance is the biggest use case.
               | There are a number of different techniques here, not just
               | noise vomit, chirp being one of the more interesting.
               | 
               | Encryption - Obviously nobody in their right mind is
               | going to sit there and scream about a tornado on an
               | encrypted channel or try to coordinate encrypted emcom.
               | Simplifying ham to the point where anyone can use it is
               | called the FRS band and as such we don't need to worry
               | about that here. There are plenty of useful cases though,
               | remote command/telemetry being only one of many.
               | Experimenting with encrypted modes/algorithms/hardware is
               | the most relevant, as well as just wanting the ability to
               | have a private conversation from time to time. Lets also
               | not forget that it's legal in Europe and they have yet to
               | meet a firey ham demise.
               | 
               | 2021 - and with these rules there never will be one.
               | Private industry has no interest but spectrum is finite
               | and human needs are infinite. Developing such a mode
               | would be extremely useful if the FCC ever gets around to
               | increasing the size and number of ISM bands as more
               | applications arise.
               | 
               | I'd be willing to meet you with this: the HF bands are
               | touchy, I fully agree there's a legitimate interest in
               | keeping things the way they are >=20m. I think the wild
               | west should really open up at VHF and above however.
               | There just isn't any use save one repeater out of
               | hundreds every few hours in a sea of blue waterfall. Even
               | if encryption/SS/WB/whatever was legalized on 2m/70cm and
               | WILDLY abused (it wouldn't be) I don't think anyone would
               | really even notice.
        
           | fortran77 wrote:
           | I've been an Extra since 1977. My pants are not scared off.
        
           | poetaster wrote:
           | Old guard. VLM is in the right. As a kid i was a terror.
           | Killowatts of power. Irressistable! But we decided, ricky and
           | i, to stick to fm. I do not believe we were loved.
        
           | giantrobot wrote:
           | Radio engineering doesn't mesh well with a "move fast and
           | break things" world view. Often the things you're breaking
           | mean _other_ people are losing out.
           | 
           | The world of HF is very different from higher bands because
           | of propagation and low band width (especially for hams). With
           | a well tuned antenna even a relatively modest transmitter can
           | DX hundreds or thousands of miles.
           | 
           | * The low band width on HF with a high noise floor makes high
           | symbol rates pointless throughout the band. You'd need so
           | much FEC there'd be little benefit from the higher rates. A
           | symbol rate that might work fine for contacts a hundred miles
           | apart will just be noise for contacts five hundred miles
           | away. Because of DXing on HF it's entirely possible to have
           | your transmissions picked up across the hemisphere.
           | 
           | * Likewise symbol rate negotiation is problematic because of
           | propagation. Transmissions aren't point to point links even
           | if you're addressing a particular station. Like the point
           | above symbol rates that work for two stations will not
           | necessarily work for all stations that will receive the
           | signal. That's just more noise for them and an inability to
           | use that part of the band.
           | 
           | * The band width for hams on HF is too small for spread
           | spectrum comms to be useful. Yet again transmissions that
           | work in some conditions won't necessarily work everywhere the
           | transmission reaches.
           | 
           | * Quick, what's the difference between an encrypted signal
           | with a long duty cycle and noise? NOTHING. Every aspect of
           | ham radio comes back down to being good stewards of a scarce
           | resource and sharing it.
           | 
           | If you blast your headphones you're not going to affect me
           | living next door. You can listen to whatever you want at any
           | volume. If you blow out your ear drums that's your business.
           | If you instead blast your big-ass stereo speakers now you're
           | affecting me next door. You've got a right to blast out your
           | eardrums, not mine.
           | 
           | Radio, like the air between our houses, is a shared medium.
           | There's bands where if you want to blast signals or play
           | around with different modes, I'll never detect it even living
           | next door. There's also bands, like HF, where you can affect
           | my use of the band even on opposite sides of the state. You
           | don't have more of a right to hams bands than I do. If you
           | want to blast high powered wide bandwidth transmissions,
           | petition the FCC to buy a license to some spectrum (good
           | luck).
           | 
           | The issue isn't graybeard hams being afraid of new fangled
           | technology. While those do exist the much bigger issue is the
           | whole of the HF band (and all uses of it) could fit in a
           | _single_ WiFi channel with room to spare. Of that tiny space
           | hams have privileges on a tiny subsection. To even use that
           | tiny subsection requires advanced licensing and a fair
           | investment in equipment. Any individual user wants to put
           | that time /money investment to use but so does every other
           | user. It's hard to share a sliver of bandwidth if there's a
           | couple assholes essentially blasting out noise all across
           | that sliver of spectrum.
        
         | p1mrx wrote:
         | > more power to them.
         | 
         | "At all times, transmitter power must be the minimum necessary
         | to carry out the desired communications."
         | 
         | http://www.arrl.org/frequency-allocations
        
           | only_as_i_fall wrote:
           | The minimum required amount of power to them.
        
             | iseanstevens wrote:
             | Nice, that actually works pretty well as a social construct
             | for government/leadership.
        
       | jeffrogers wrote:
       | Hoping municipalities around the country note that the amateur
       | radio programs they've been depreciating over the last decade
       | actually have a role to play in emergencies like major
       | hurricanes, floods, and earthquakes.
        
       | h2odragon wrote:
       | I'm sure we all thank the FCC for its gracious permission here.
       | 
       | > In 2016, in response to an ARRL petition for rulemaking, the
       | FCC proposed to remove the symbol rate limitations, which it
       | tentatively concluded had become unnecessary due to advances in
       | modulation techniques and no longer served a useful purpose. That
       | proceeding, WT Docket 16-239, is still pending.
       | 
       | I'm certainly grateful that the custodians of such a valuable
       | public resource as "radio communication" are taking such a
       | deliberate, measured approach to their jobs. Just imagine the
       | horror and chaos that could descend if we allowed higher bandwith
       | digital comms over these frequencies... People might send _porn_!
       | 
       | (This is sarcastic, in case the bots need the hint)
        
         | geofft wrote:
         | http://www.arrl.org/news/view/fcc-agrees-to-90-day-pause-in-...
         | 
         | > _The Commission 's proposed changes differed from the ARRL's
         | initial filing and caused the ARRL to be concerned about
         | possible interference to current users resulting from the
         | deletion of the ARRL's requested 2.8 kHz bandwidth limitation.
         | Due to those concerns the League filed comments with the FCC
         | opposing the deletion of the requested bandwidth._
         | 
         | The ARRL is asking the FCC to not drop the rule entirely.
        
         | lolthishuman wrote:
         | Why is it regulated anyway? What's the balance at play? Limits?
        
           | VLM wrote:
           | Fcc part 97.101 "General Standards" (d): "No amateur operator
           | shall willfully or maliciously interfere with or cause
           | interference to any radio communication or signal."
           | 
           | Pitiful we have to encode "the golden rule" of treat others
           | like you'd have them treat you into law, but here we are its
           | in the CFR.
           | 
           | As of 2021 no one has a technological answer to how to avoid
           | various wide band digital technologies from interference
           | against, well, absolutely everything else currently in use,
           | without forcing everyone to operate in a channelized system
           | with massive international coordination problems. The
           | international part is a nightmare, what if, I donno, Bulgaria
           | refuses to channelize? Nothing will work for anyone unless
           | everyone cooperates.
           | 
           | Wideband digital modes do NOT play well with others.
           | 
           | There are channelized bands around 5 mhz (in the usa) and the
           | FCC does relax quite a bit on wide open microwave bands, but
           | people are going to request turning all of 20 meters into one
           | single user digital channel, and to hell with everyone else
           | currently using the band, apparently into infinity. Its an
           | eternal meme.
           | 
           | I guess the best analogy I can come up with, is you can zone
           | land as a public park for people to picnic, but that doesn't
           | mean the land is completely lawless, if you blast your music
           | at 160 dB the police will arrest you for preventing everyone
           | else from enjoying their picnic.
           | 
           | We easily right now have the technological ability to turn
           | the 20M band into a single channel, single user, very high
           | speed digital path at 1500 watts. But that's a terrible idea,
           | given the zillions of current users, local and international,
           | who would be kicked off completely unable to operate.
        
           | makomk wrote:
           | There's very limited bandwidth available on most of the ham
           | radio bands and other users don't want people taking up large
           | chunks of bandwidth with wide, high-bitrate data signals and
           | making the bands unusable for everyone else.
        
           | chociej wrote:
           | To get one of the big things out of the way: bandwidth. The
           | FCC don't want anyone taking up big chunks of spectrum
           | without using a license or service appropriate to that use.
           | Notably, they don't want a few users to be able to chew up
           | entire bands.
           | 
           | But there's a philosophical part to the discussion also. The
           | tradeoff goes like this: hams get some really nice spectrum
           | assignments, low fees, self-regulation, experimental modes
           | and techniques, etc. In exchange, they can't use the amateur
           | radio service commercially or for non-personal aims, and
           | specifically they are expected to focus mostly on learning,
           | community interaction, public service, experimentation, and
           | so on. They also want amateur modes to be somewhat
           | approachable, i.e. not requiring exotic or expensive
           | hardware, necessarily.
           | 
           | Should an operator wish to use the radio spectrum for
           | commercial or highly productive use, especially one requiring
           | significant bandwidth, secrecy, exclusivity, etc, they are
           | expected to use a different license / service more
           | appropriate to those needs.
           | 
           | Basically:
           | 
           | Tinkering, chit-chat, community service, narrow bandwidths =>
           | amateur radio
           | 
           | Anything else => get a different license
           | 
           | To that end it was long the FCC's stance that high symbol
           | rates sort of implied that you're going outside the purposes
           | of the amateur radio service. With digital communication
           | having developed as much as it has, though, it's reasonable
           | that hams want to be able to do more interesting things with
           | digital modes, which generally means higher symbol rates.
        
             | leephillips wrote:
             | An interesting twist to the regulations is that you're not
             | allowed to use ham radio as a substitute for cell service.
             | I never quite understood this rule, nor how it was to be
             | enforced; but it would seem to place some limits on the
             | permissible chit-chat.
             | 
             | Also: no encryption.
        
               | VLM wrote:
               | > substitute for cell service
               | 
               | 47 CFR 97.113 Prohibited transmissions, (a) No amateur
               | station shall transmit: (5) Communications, on a regular
               | basis, which could reasonably be furnished alternatively
               | through other radio services.
               | 
               | The FCC has a perfectly good part 22 service for cell
               | phones.
               | 
               | Or FCC part 73 regulates "old fashioned broadcast radio"
               | 
               | Per 97.1 (a) thru (e) explain the purpose of amateur
               | radio but it boils down to something like a national
               | park, sorta. The purpose of the service is NOT to avoid
               | existing regulation.
               | 
               | "on a regular basis" means experiment as much as
               | possible, for free, non-professionally, as a ham, but if
               | you try to set up a formal cell phone company business
               | for the public just like AT&T, and try to tell the FCC
               | you prefer being regulated under part 97 and pay only $35
               | for a license, the FCC will be very very very mad at you,
               | wave 47 cfr 97.113(a)(5) at you, then regulate you under
               | part 22.
               | 
               | The FCC has nothing against people building broadcast
               | radio services; but if you try to demand they regulate
               | your public broadcast FM radio service under part 97
               | rules, the FCC is warning you they will absolutely insist
               | on regulating and charging you under part 73 rules...
        
               | poetaster wrote:
               | Service. In the sense of serving!? My two FM episodes, 25
               | years apart, were service. Not for regulatory purposes.
               | To those, we but poor wee pirates were, and remain.
        
               | leephillips wrote:
               | > Communications, on a regular basis, which could
               | reasonably be furnished alternatively through other radio
               | services.
               | 
               | I guess this was the bit I had in mind. It means that one
               | can't use amateur radio for what a cell phone is normally
               | used for, doesn't it? Like calling your ham friends to
               | make arrangements for poker night. Or is that the wrong
               | interpretation?
        
               | VLM wrote:
               | That example is fine its not a regular basis.
               | 
               | Note you can run a business on a cell phone or do
               | financial transactions or speak swear words or all kinds
               | of things common carriers supposedly don't care about but
               | would be banned on ham radio. Also ham radio has no SLA
               | or mandatory 911 access like a phone. Consider... if you
               | are a casino operator and you're trying to book hotel
               | rooms for these guys to play poker night at your casino,
               | that would be forbidden under part 97 because its a
               | business and part 97 isn't for business use.
               | 
               | Its definitely an intent based situation. "Fooling around
               | with radio technology while having convos of a non-
               | commercial personal nature to promote international
               | goodwill and gain radio operating experience" is
               | literally what part 97 was designed for, and fits the
               | poker game example perfectly. "We built a nationwide
               | cellphone network but forgot to budget for FCC licensing
               | fees so we'll reprogram to use ham radio freqs and lie to
               | the FCC and tell them its a part 97 ham radio, while we
               | sell it to the general public as a cell phone" would be
               | quite stunningly illegal because it would be perfectly
               | reasonable to operate a commercial cell phone network
               | under existing FCC regulations for commercial cell phone
               | providers, and its done on a regular basis by the famous
               | big name nationwide cell phone services every day...
        
               | second--shift wrote:
               | I've heard this several times about ham radio, and to me
               | as an outsider the idea of shared access to the medium is
               | a bit off-putting to me.
               | 
               | Is it possible to have two-way links "in the clear" but
               | otherwise encoded or ciphered? Is there a regulation that
               | says all transmissions must be in English, for example,
               | or can I transmit in Esperanto/Navajo/hex?
        
               | jandrese wrote:
               | The big limitation is no encryption. So it's only a
               | substitute for cell service if you're ok with being on a
               | big party line with everybody else in the vicinity.
        
             | burnished wrote:
             | Thanks for the additional context!
        
             | madengr wrote:
             | I'm wondering if you could legalese around it since a PRN
             | is a chip, not a symbol, as the former has no information.
             | So one could spread a low symbol rate into a high chip
             | rate.
        
           | CobaltFire wrote:
           | It's limited because they don't want to create a defacto
           | lower limit on what it costs to start using HAM bands.
           | 
           | That said, I agree it's taking too long. The technology for
           | the higher symbol rates is now cheap enough to be a non-
           | issue.
        
           | pgt wrote:
           | Presumably for the same reason that GPS time signals had
           | (have?) pseudorandom noise added: to prevent an adversary
           | from using your own systems to steer missiles with high
           | precision.
        
             | madengr wrote:
             | GPS uses PN codes for the timing difference measurement, as
             | well as allowing multiple satellites on a single channel. I
             | believe the dithering (selective availability) was turned
             | off years ago, thus the L2 channel ads only ionospheric
             | correction (which can also be accomplished with local
             | sources).
             | 
             | The FCC symbol rate limitation needs to go. It's a
             | hindrance on HAM radio. Just regulate it by bandwidth, or
             | better yet EIRP PSD, but that would be tough to control.
        
               | jaywalk wrote:
               | Yes, Selective Availability was turned off in 2000 and
               | will never be re-enabled. In fact, the latest generation
               | of GPS satellites do not even support Selective
               | Availability:
               | https://www.gps.gov/systems/gps/modernization/sa/
        
             | morcheeba wrote:
             | PRN (Pseudorandom noise) in the context of GPS is just a
             | coding standard - it's just CDMA (aka Spread Spectrum) and
             | it allows all satellite to use the same frequency. A side
             | benefit is that the signals can be below the noise floor,
             | and when you apply the gain from decoding, it rises the
             | signal above the noise floor (exactly like how you can pick
             | out a voice in a crowded bar if you know what that voice
             | sounds like).
        
           | nomel wrote:
           | Why is this downvoted? The purpose and limitations of RF
           | bandwidth allocation isn't exactly widely known.
        
             | h2odragon wrote:
             | Truly. I have philosophical problems with the existence of
             | the FCC but there's a great deal of interesting and
             | educational discussion to be had here.
             | 
             | At the risk of delving further into conspiracy theory I
             | suspect that may be a reason its downvoted; because there's
             | room for debate. There's currently a lot of feeling that
             | once the government is involved debate must be silenced.
        
               | geofft wrote:
               | I didn't downvote it, but I strongly suspect it was
               | because of the sarcasm, the meta-sarcasm, and ultimately
               | the _unwillingness_ to believe that interesting opposing
               | arguments might exist. That is, the post didn 't
               | encourage interesting and educational discussion, just
               | derision. The merit of the resulting conversation was
               | despite the initial post, not because of it.
        
       | gorgoiler wrote:
       | What's the technology here? I'm amateur licensed and really in
       | the market for a radio pager. Asynchronous short messages would
       | really help me out.
        
         | clipradiowallet wrote:
         | The TLDR is packet radio speed caps and frequency restrictions
         | are being [temporarily] lifted for Ida-related communications.
         | 
         | PS: the world needs more hams!
        
           | post_break wrote:
           | Maybe if the existing hams didn't gate keep. They are the
           | perfect example of a hobby that is hostile to newcomers.
        
             | kragen wrote:
             | They're gatekeeping so you don't drown out their
             | conversations with their friends by radiating kilowatts of
             | noise because you think it's cool (or make money that way).
             | Like what happened to Usenet as the internet got
             | commercialized.
        
             | imroot wrote:
             | I'm not going to say that it doesn't happen, but, honestly,
             | most of the folks who I've met in my journey with Amateur
             | radio are folks who are truly excited about RF and who want
             | to share their knowledge in the hobby to others.
        
             | bityard wrote:
             | I keep hearing this meme but think it's either overblown,
             | or used as an excuse to avoid the hobby just because they
             | are outside of the typical ham radio demographic.
             | 
             | I got my license a few years ago and nearly everyone I've
             | ever interacted with has been friendly and willing to help
             | if I need it. Yes, there are asshats on the air, just like
             | there are asshats on the Internet and everywhere else. You
             | just don't talk to them.
        
             | mortenlarsen wrote:
             | Not in my experience. Everyone was very welcoming. And many
             | were actively doing outreach.
             | 
             | I got my "Radio Amateur Extra" license in August of last
             | year.
        
             | progman32 wrote:
             | (Not a ham - but thinking of becoming one): Are you
             | referring to the exam, or something else?
             | 
             | I find entrance exams are almost always orthogonal to
             | actual performance (like tech interviews). I think it
             | should be limited to verifying an understanding of safety
             | and the law only. Everything else can be quickly and easily
             | looked up if needed. If I make a fool of myself on the air
             | that's on me.
             | 
             | Take a look at the question pool: http://www.arrl.org/files
             | /file/VEs/2019-2023%20General%20Cla...
             | 
             | Say we limit the exam to subelements G0 (Safety), G1
             | (Commission's Rules), G2 (Operating Procedures), and G4
             | (Amateur Radio Practices). What's the downside? Why are we
             | asking people about Digital circuits; amplifiers and
             | oscillators (G7B), Analog and digital integrated circuits
             | (ICs); memory; I/O devices; microwave ICs (MMICs); display
             | devices; connectors; ferrite cores (G6B), etc? I agree it's
             | useful information, but if all I want to do is operate my
             | radio, why gatekeep on this other knowledge? Is my
             | incomplete understanding blinding me?
        
               | clipradiowallet wrote:
               | > (Not a ham - but thinking of becoming one)
               | 
               | Do it! I used "Ham Radio Prep"(google, it's the first
               | result). It was really informative for me. They have a
               | linear lesson plan with videos/tests to help you learn
               | what you need, and then retain that information. After it
               | was done, I felt very prepared for the exam, and the
               | actual exam went very smoothly. As a side effect, I
               | learned a lot about RF that I was ignorant of in the
               | past, and thoroughly enjoyed the entire process. Can't
               | recommend getting into amateur radio enough, it was one
               | of those moments where I realized there was a giant gap
               | in my general how-radio-works knowledge.
        
               | coldpie wrote:
               | The nerd in me finds the idea of knowing how to operate a
               | radio vaguely appealing, but once you can do so and are
               | licensed, what do you actually _do_ with it? Just like,
               | talk to a couple other guys about... what they had for
               | lunch today? Is it just a way to communicate with people?
               | Once you 've invested the hours and money, what do you
               | have on the other side? I ask this question entirely out
               | of ignorance, sincerely I mean no malice with this.
        
               | dpifke wrote:
               | I just finished running the Hood to Coast relay race
               | (https://hoodtocoast.com). One of my team's runners
               | followed someone else down the wrong fork of the road,
               | and ended up miles off course in an area with zero cell
               | phone coverage. The volunteer hams helping with emergency
               | communications for the race were critical for
               | coordinating the search. We made sure they didn't have to
               | pay for their own beer at the finish line party.
        
               | dexterhaslem wrote:
               | there's a lot of variety out there. you can spend your
               | entire ticket dorking out on digital modes (esp if you go
               | for general+ and have access to lower bands) like FT8,
               | FT4, Olivia, WSPR [0] to see how far out you can get on
               | as little power as possible and so on.
               | 
               | Or if you want to ease into it, you can get a ham radio
               | w/o a license, or cheap SDR and try to receive and decode
               | weather sats, etc [1]
               | 
               | making tiny WSPR boards and things like APRS [2] interest
               | me more than ragchewing or nets on 40 or 80 meters most
               | of the time
               | 
               | forgot my favorite, amateur SSTV (analog baby!) - can see
               | some analog and hybrid (easylink over internet..
               | cheating) http://www.g0hwc.com/
               | 
               | 0 - http://wsprd.vk7jj.com/ (click search then map to get
               | an idea)
               | 
               | 1 https://www.rtl-sdr.com/using-50-lines-of-python-code-
               | to-dec...
               | 
               | 2 https://aprs.fi/
        
               | clipradiowallet wrote:
               | > talk to a couple other guys about... what they had for
               | lunch today?
               | 
               | Sometimes we talk about the weather, haha. The most
               | common time I use my radio is during bad weather,
               | especially if there are tornado warnings nearby. There
               | are [tornado] spotters using the same local repeater in
               | our area, and sometimes it can be comforting to hear them
               | report a tornado is moving away from you, or dissipating.
               | Otherwise, I think we don't have much to talk about until
               | there is an emergency of some kind.
               | 
               | One thing I like isn't something you need a license to
               | do, but a radio is a great way to listen to existing
               | traffic outside the bands a normal "scanner" would
               | supply. Everything from drive-thru speakers to casino
               | security uses VHF/UHF frequencies, so with a decent dual
               | band handheld you can listen to everything, which can be
               | amusing sometimes.
               | 
               | Another fun bit, is you can look up registered/reserved
               | frequencies on the FCC website. You can't [legally]
               | broadcast on these, but it can be interesting to see all
               | these reserved frequencies and listen in. Sometimes
               | you'll hear chatter among commercial farmers, other times
               | electrical linemen...it's a mixed bag. I also tune into
               | the local county/city emergency frequencies from time to
               | time. I live in a very small rural area, so if you hear
               | sirens, typically I can turn on my radio and alternate
               | between the fire/police/ems frequencies and find out what
               | the sirens were for.
        
               | 7402 wrote:
               | The reason to gatekeep on that knowledge is because the
               | Amateur license is unique in giving you the legal
               | authority to design and build your own transmitters and
               | antennas, and to operate on dozens of bands from 135 kHz
               | to 275 GHz and up, at powers up to 1500 watts. If you
               | just want to operate a store-bought radio, there are much
               | easier ways to go about it, e.g., MURS, GMRS, FRS, CB.
               | 
               | Also the Technician-class ham license has an easier test
               | than the General-class one linked above. It's certainly
               | reasonable to start with that one.
        
               | progman32 wrote:
               | That's fair, and yet the exam doesn't seem to
               | differentiate on what I want to work on. If I don't know
               | about how ICs work or can't exactly remember what the
               | speed of light is, should that prevent me from getting a
               | license? What if I'm mostly interested in SDR? Should
               | that prevent me from being part of the safety net that
               | hams claim to provide? What about participating in other
               | aspects of the hobby, like DX, general socializing,
               | operating a relay, communicating with space hardware,
               | etc?
               | 
               | I guess I'm unclear what the concrete value of
               | gatekeeping on sections other than the ones I listed are.
        
               | giantrobot wrote:
               | Most SDRs are RX only so there's zero need for a license
               | for them. As for the other points, the Technician license
               | is super easy and you can pass it with minimal study.
               | 
               | If you _can 't_ pass the Technician exam, you'd actually
               | be hard pressed to meaninvcully participate in those
               | activities you listed. If you don't know the regulations
               | around operating a repeater how are you going to operate
               | a repeater? If you don't understand just a little about
               | radio propagation how are you going to actually do any
               | DXing or communicate with space hardware?
               | 
               | Ham licenses exist because radio transmissions affect
               | _other_ people and not just yourself. If you don 't know
               | what you're doing to can keep _me_ , your neighbor, from
               | participating in the hobby because your TX power is too
               | high or your antenna is just an untuned jamming device.
        
               | mike_d wrote:
               | There is never a legitimate reason to gatekeep knowledge.
               | 
               | Every time I hear this pearl clutching from hams I like
               | to remind them that the biggest threat to their hobby
               | isn't rouge transmitters and antennas or someone stepping
               | on their transmission - but nobody giving a shit about
               | them anymore.
               | 
               | If you keep new people from entering the hobby it will
               | completely die off and eventually all that spectrum will
               | be reallocated to useful things like cellular.
        
               | tshaddox wrote:
               | Gatekeeping _on_ the knowledge. Not gatekeeping the
               | knowledge.
        
               | Retric wrote:
               | Yes, it's a lot like fireworks as a hobby. Everyone has
               | easy and open access to the basics ie walkie-
               | talkie/bottle rockets, it's only the higher powered
               | versions that require a license.
               | 
               | For example:
               | https://en.wikipedia.org/wiki/Family_Radio_Service
        
             | clipradiowallet wrote:
             | What do you mean? I ask as a ham myself..I took my exam
             | [remotely] in 2020. So far all of my contacts in my area
             | have been pretty warm greetings. I generally get the
             | impression that existing hams like seeing new hams pop up.
             | 
             | That said, I live in a _very_ rural area, and imagine that
             | more congested areas(cities) might be less welcoming of new
             | traffic.
        
               | bityard wrote:
               | > and imagine that more congested areas(cities) might be
               | less welcoming of new traffic.
               | 
               | I live right next door to a very large metropolitan area
               | and the advantage is that there is a lot of diversity in
               | terms of who is on the air. I have 50 repeaters
               | programmed into my dual-band radio and almost all of them
               | some kind of regular activity from weekly nets to casual
               | drive-time QSOs. Lots of older retired gentlemen of
               | course but plenty of other stuff going on too.
        
       | molticrystal wrote:
       | I wonder how this compares to their previous statements and
       | policies, because with a million people out of power and most
       | communication systems offline, it does seem that charging people
       | is just wrong, and the lack of the necessity of emergency
       | communication provided by Amateurs was stated as a reason for
       | them not exempting them from licensing fees.
       | 
       | >The FCC also disagreed with those who argued that amateur radio
       | licensees should be exempt from fees because of their public
       | service contribution during emergencies and disasters.
       | 
       | >"[W]e we are very much aware of these laudable and important
       | services amateur radio licensees provide to the American public,"
       | the FCC said, but noted that specific exemptions provided under
       | Section 8 of the so-called "Ray Baum's Act" requiring the FCC to
       | assess the fees do not apply to amateur radio personal licenses.
       | "Emergency communications, for example, are voluntary and are not
       | required by our rules," the FCC noted. "As we have noted
       | previously, '[w]hile the value of the amateur service to the
       | public as a voluntary noncommercial communications service,
       | particularly with respect to providing emergency communications,
       | is one of the underlying principles of the amateur service, the
       | amateur service is not an emergency radio service.'" [0]
       | 
       | https://www.arrl.org/news/fcc-reduces-proposed-amateur-radio...
        
       | lxe wrote:
       | There are some papers on wideband / high speed HF communication
       | techniques. Most applications are basically backup for military
       | applications when satellite communication fails.
       | 
       | I think it's an interesting topic, but with mesh networks and
       | satellites, HF high speed links are not as relevant.
        
         | adrianpike wrote:
         | Got any links? I've been deep diving into NVIS lately and would
         | love to have more reading material.
        
         | CobaltFire wrote:
         | HF fills a different niche than mesh and satellite.
         | 
         | Satellite has a reasonably high lower bound for implementation,
         | and is reasonably easily disrupted.
         | 
         | Mesh is reliant on a relatively high density of relays;
         | typically you need nodes within a couple of miles of each other
         | depending on terrain.
         | 
         | HF allows for significantly larger mesh network node distances
         | (with lower data rate) or much more robust communication that
         | is harder to shut down.
        
       | tlrobinson wrote:
       | Can anyone provide background on why there's a limit on symbol
       | rate at all? Isn't bandwidth a more appropriate limit?
        
         | wyager wrote:
         | Yes. Dumb historical decision. People have been trying to get
         | it overturned for a while.
        
         | VLM wrote:
         | There are some content regulations so transmitting "in the
         | clear" for all to read is generally demanded by the .gov.
         | 
         | Groundwave HF paths technologically don't have much of a symbol
         | rate limit. You could talk from ND to SD using a quite fast
         | symbol rate as long as its a groundwave path under 25 miles or
         | so. There are limits, but they're huge.
         | 
         | Skywave "ionosphere bounce" paths have massive multipath issues
         | although slow enough symbol rates can make it thru without too
         | much intersymbol interference. These paths are worldwide.
         | 
         | Even with existing limits, its quite trivial to transmit a
         | modulation that has too fast of a symbol rate for skywave /
         | international paths.
         | 
         | I guess I'm just pointing out the existing rate limits are "too
         | high" often for international communication. You could turn 10M
         | into some kind of short range local wifi I suppose, but all
         | anyone more than a hundred miles away would hear would be noise
         | / interference due to intersymbol interference and multipath.
         | 
         | Supposedly, in my grandpa's day, the government regulated
         | modulation method to a precise detailed level so if you're only
         | allowed to transmit 45 baud ITU2 encoded rtty FSK, specifying a
         | dozen of one or 12 of another is the same thing, just depends
         | how you say it. Then they removed detailed mode regulation "do
         | what you want, grandfathering in existing users".
         | 
         | Regulation can take awhile to change with the times. Again,
         | supposedly in my grandpa's day, wattmeters were not accurate
         | enough to be useful so the government regulated DC input power
         | because voltmeters and ammeters are accurate enough for a
         | ballpark guess. See also peak power vs "peak envelope power"
         | aka PEP measurements for analog single sideband voice. So
         | bringing it back around, at one point symbol rate was a
         | reasonable proxy for old fashioned rtty fsk bandwidth
         | regulation.
        
         | topspin wrote:
         | It's just history and regulatory inertia. The rules were
         | established when digital radio was nascent and available
         | technology limited the modulation techniques that were
         | feasible. Digital on some bands is regulated on bandwidth; the
         | 70 cm band has a bandwidth limit of 100 kilohertz for
         | "unspecified digital codes."
        
           | drmpeg wrote:
           | The 70 cm rule is the silliest. The limit for digital data is
           | 100 kHz, but you can legally transmit 6 MHz wide analog
           | television. Because wide bandwidth video is allowed, digital
           | video modes like DVB-S, DVB-T and ATSC are also allowed. To
           | get around the 100 kHz restriction for data, some folks are
           | running links with 95% data and a low rate video sub-stream.
        
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       (page generated 2021-08-30 23:00 UTC)