[HN Gopher] Vintage radio broadcasting equipment
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Vintage radio broadcasting equipment
Author : j4yav
Score : 77 points
Date : 2022-01-26 12:48 UTC (10 hours ago)
(HTM) web link (www.oldradio.com)
(TXT) w3m dump (www.oldradio.com)
| WalterBright wrote:
| Caltech had a pirate station when I was there, naturally dubbed
| "KCAL". The equipment was all custom designed and built by the
| local EEs. What I remember most about it was the lovingly
| machined panels made for it. It was a beauty. I wonder whatever
| happened to it.
| IndySun wrote:
| Of similar interest...
|
| http://oldradios.com/radios/index.htm
|
| Not quite abandoned but not recently updated.
| marcodiego wrote:
| Spark gap transmitter were (one of?) the first form of radio
| broadcasting: https://en.wikipedia.org/wiki/Spark-gap_transmitter
| . Since it is not very selective - its signal spreads through the
| whole spectrum - its use is forbidden today; think a single radio
| station which transmitter over all frequencies, like you can turn
| the dial and it will always interfere and you can't get rid of
| it.
|
| Because tuning was a known "phenomenon" and having the
| possibility of using the radio spectrum for multiple transmission
| was desirable, efforts began to make transmissions more selective
| so they wouldn't pollute the whole radio spectrum.
|
| Radio pioneers didn't have anything close to modern small,
| powerful, solid state, very close to sine oscillators at the
| time. They had to use what was available so they could modulate
| their transmission. In a simplified model, a radio transmission
| be thought of as an antenna whose electric potential varies with
| the sine of time at, for AM broadcasts, the order for hundred of
| kilohertz. This oscillation is then "multiplied" by the signal
| one want to transmit. Better results occur when the "transmitted
| signal" (think about it as something close to a payload) has a
| much lower frequency than the "carrier": the frequency at which
| the potential of the antenna would oscillate to transmit a
| constant value.
|
| Now, early broadcast really worked around the technology
| available at the time. To oscillate the electric potential of the
| antenna, they resorted to eletromechanical methods. Very
| interesting solutions were developed:
| https://en.wikipedia.org/wiki/Spark-gap_transmitter#Rotary_g...
| seiferteric wrote:
| I actually made a spark gap "receiver" when I was a kid
| following some plans I found. I used a rubber tube with a metal
| rod in one end, then filled partially with iron filings I made
| from filing a pipe, then stuck another metal rod to plug the
| other end of the tube slightly compressing the filings. I then
| placed a LED, resistor and battery in series with the device.
| If the LED turns on, flick the device until it is off. Then
| place next to my gas stove and click the gas spark igniter. If
| all goes well, the spark will iron align some of the iron
| filings to create a conductive path and the LED will turn on.
| Flick again to turn off.
| st_goliath wrote:
| > Spark gap transmitter were (one of?) the first form of radio
| broadcasting
|
| AFAIK this is also the reason the German language uses the word
| _funken_ for transmitting wireless broadcasts, derived from
| _Funke_ (spark). And of course the corresponding noun _Funk_ ,
| often embedded in typical, lengthy noun constructs.
|
| The German company _Telefunken_ also has a couple mentions in
| the Wikipedia article you linked to, as one of the early
| manufacturer of commercial radio equipment.
| imroot wrote:
| The first job I ever had was at a Radio station, where we were
| transitioning away from Harris 90 automation to an AudioVault/BEI
| controlled automation.
|
| The only reason I got the job is because I could figure out how
| to use the interface: the other two kids from high school who
| went with me couldn't manage to record audio from the interview.
|
| I remember so many late nights running football, basketball, and
| other games during the summer...only to turn around and do an
| afternoon game the next day, then my usual 4-midnight station
| rotation, all while making around $5/hour.
| mikewarot wrote:
| A friend of mine bought the transmitter from an AM radio station
| that went out of business to use as a ham radio transmitter...
| how they managed to shove it into his basement is beyond me. He
| ran it on its low power setting, and everyone loved the quality
| of his audio.
| MrRadar wrote:
| Mr. Carlson has one of those, and had a video demonstrating it:
| https://youtu.be/ZzpVhCL5aPg
| tyingq wrote:
| Signal generators (common test equipment) can also be used as
| broadcasters. I recall doing this a long time ago with an old HP
| 8640B. It has both AM and FM modulation. Not much output power,
| but the output power is adjustable so that you can experiment
| without creating issues for anyone else.
| bdavis__ wrote:
| HP 8640B puts out a clean and precise waveform. wonderful piece
| of test equipment from the world of RF.
|
| put a short wire on the output, and tune it to 146.34 (for a
| second). bang, the local repeater will kerchunk.
| h2odragon wrote:
| great resource. random click led me to this 150kw vacuum tube:
| https://www.oldradio.com/archives/hardware/WE320A.htm
| BigTuna wrote:
| I'm currently working on getting a retired Broadcast Electronics
| 2100C cart machine from my old college radio station and as I
| expected the parts appear to be very hard to come by. If anyone
| has a suggestion/lead I'd be grateful.
| jmacd wrote:
| In the late 90s, while in high school, I built an FM transmitter
| and with a few friends ran a weekend pirate ration station. (AMF
| - Anonymous Mother ....)
|
| The kit was sold by a company called Ramsay Electronics. It was 1
| watt and with the right antenna (which was quite visible on the
| roof of my friend's house. They lived right at the top of a hill)
| it did a good job of covering our small town. There was a brief
| time when we would get word of several house parties all tuning
| in when we started to play more dance music late at night. There
| would be requests from people all through the week at school to
| play this or that, or call a certain number because someone
| wanted to say something. This time also coincided with the very
| first MP3s and I was a "Vice President" of an irc "courier"
| group, so we could get all the latest stuff!
|
| It only lasted one school year and my friends loved the
| notoriety, but I used to just sit there and day dream about the
| audio passing through the low and high pass filters that I had
| been constantly tweaking, and then being modulated and then re
| amplified before being pushed out. I still get an excited
| sensation just thinking about it.
| myself248 wrote:
| > excited
|
| ...
|
| Peak in-joke, right there.
| Cthulhu_ wrote:
| We had a baby monitor that apparently broadcasted on AM, a
| cassette player, and a lot of shouting and we weren't afraid to
| use it :p. I'm not sure it even worked outside the confines of
| our own house.
| resters wrote:
| great story!
|
| I believe 1 watt may actually be legal, so it was not actually
| pirate radio from an FCC perspective, only an RIAA perspective.
| alamortsubite wrote:
| The output of the original Ramsey kits was about 25 mW, which
| was FCC-compliant. The one watt kits used a MRF557 transistor
| (rated for up to 1.5 watts) and were definitely illegal to
| operate in the U.S. without a license. They were sold in the
| U.S. as "export" models for overseas use only. I may be
| wrong, but I think this eventually got them in hot water with
| the FCC and led to them discontinuing the kits.
| j4yav wrote:
| My father was a radio DJ and so I grew up after school in local
| radio stations during the 80s and 90s. I hope someone else gets a
| kick out of seeing this old radio broadcasting equipment.
| technothrasher wrote:
| I definitely get a kick out of seeing it, very nostalgic. I had
| a few shows on my college radio station (88.5 WRUR in
| Rochester, NY) back in the early 90's, including the 9am news
| slot on Friday mornings and a brutal 3-6am slot on Wednesday
| mornings where I did whatever the heck I wanted (nobody was
| listening at that hour anyway).
| antihero wrote:
| I remember DJing a drum & bass hour...at 9AM on a Monday
| morning on my uni radio station. I don't think I had many
| listeners.
| anthk wrote:
| Today if you head to SDF or some tildes you can DJ online
| to a streaming server, among other geeky stuff inside
| (those are public Unix machines to learn and share).
|
| SDF has Anonradio:
|
| https://anonradio.net/
| zevra wrote:
| I'm currently at WRUR. It is not the same as it was in the
| 90s but we're still here. If you have any cool stories I'd
| love to hear them. They are a little more strict these days.
| technothrasher wrote:
| I was back on campus about two years ago and the studio was
| almost unrecognizable, although the rest of Todd Union
| looked about the same! Yeah, we weren't very strict back in
| those days. You just had to do so many hours in the AM
| booth and then you were given access to the FM studio. So
| you just did your AM time by playing album sides while you
| did your homework; nobody was listening to AM anyway.
|
| Not too many exciting stories. I got the opportunity to sub
| for somebody in the 5pm Friday slot one week. I had no idea
| what the slot was, but I just went in and did my 3am show.
| The phone lines quickly lit up with people saying, "What
| the hell is this Sh#!? You're complete crap. Where's the
| Jazz hour?" Lol. On the other end of the spectrum, one of
| the UR bus drivers recognized my voice and told me he loved
| my 9am news slot and always tuned in. I always did the top
| stories off the AP feed and then finished with some weird
| off-the-wall story, before turning it over to my buddy to
| do the sports.
| j4yav wrote:
| I love the old consoles in particular.. the ones at
| https://www.oldradio.com/archives/hardware/ba.htm are just
| beautiful.
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(page generated 2022-01-26 23:01 UTC)