[HN Gopher] The Radio Broadcaster's Dream Mini Rack
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The Radio Broadcaster's Dream Mini Rack
Author : geerlingguy
Score : 31 points
Date : 2025-04-03 14:27 UTC (2 days ago)
(HTM) web link (github.com)
(TXT) w3m dump (github.com)
| adamgordonbell wrote:
| I think but am not sure that the goal here is to deliver reliable
| audio to a transmitter at a remote site from a radio station.
| Nextgrid wrote:
| I find it curious that so many separate components are used (that
| presumably aren't cheap, as they target a low-volume, pretty
| niche industry).
|
| It seems to me that most of these can be replaced by any computer
| with an analog audio output (and since this is Jeff Geerling
| we're talking about, it can be a Raspberry PI)?
|
| Maybe put two and use the "silence detector" box to automatically
| switch between them in case one goes down?
|
| In fact, I wonder if a custom board can be designed with 2
| separate stages (each powered by a compute module and DAC) and
| some circuitry to do the silence detection and switching, with
| some GPIO lines going back to each to inform them of which one is
| being the chosen one for the final audio output. This would
| effectively condense this whole thing into a single box. But not
| being a broadcast engineer, I'm just talking out of my ass here,
| maybe there's a good reason they're doing things they way they
| do.
| cf100clunk wrote:
| The authorities are very picky about the bench-tested qualities
| of radio and television gear in professional use, and
| specialization of capabilities across different brands leads to
| best of breed gear options. It is a very serious business and I
| have the highest regard for the radio and television engineers
| who oversee such gear.
|
| For outsiders it is a bit like thinking about how an RPI5 could
| theoretically run medical gear in an operating theatre or
| control the just-in-time processes of a major factory, but
| would regulators and insurance providers go for it? For amateur
| broadcasting, sure, an RPI can have fun uses like this:
|
| https://github.com/cdzombak/pi-fm-player
| geerlingguy wrote:
| Indeed, even many of the devices here could be running on a Pi
| internally... or are running Linux on some other Arm SoC or a
| suite of microcontrollers.
|
| One of the new audio processors (full size rack) actually runs
| a small cluster of CM4s for local audio processing, a remote
| control system, and something else (can't remember), but the
| convergence from all these discrete specialized boxes to one or
| a few general PCs is slow to happen.
|
| Some of that is down to proprietary stuff, but a lot is
| inertia, and being allergic to less-tested solutions.
|
| The Inovonics box could be replaced by Stereo Tool [1] on a Pi
| --and indeed it is in some lower budget installs!
|
| A lot of radio engineers are also hams and so are willing to
| experiment sometimes, especially in lower power stations where
| the stakes aren't as high. But if you're dealing with one of
| the "big" stations or ownership that has the IBM mentality
| (nobody got fired for choosing IBM), they tend to stick to the
| tried and tested audio chain, with more robust equipment with a
| long history of support.
|
| [1] https://www.thimeo.com/stereo-tool/
| cf100clunk wrote:
| I like the compactness, and since it seems to be North American
| gear I'm wondering if additional gear like an HD Radio (IBOC)
| modulator-injector such as a Nautel HD MultiCast+ could be part
| of the chain? I wish there was progress on an open source IBOC
| exporter but it doesn't seem to be a thing and its waaay outside
| of my capabilities.
| geerlingguy wrote:
| HD Radio is still (annoyingly) covered by patents in a way that
| open source efforts like nrsc5 still can't be integrated into
| any OSS radio tooling for fear of litigation.
|
| And from my own IANAL research, it seems iffy whether the
| initial set of patents which is expiring soon are the ones that
| will open it up... or if any of the many follow up set of
| patents can keep it out of easy reverse-engineered access :(
| JKCalhoun wrote:
| While PoE is nice, I suspect most of those wall-warts output
| something like 9V or perhaps even 5V. If there are matching wall-
| warts, a small switching power supply of the same voltage (and
| combined current) would be a clean replacement.
|
| The point about a UPS is a good one though. There is certainly an
| efficiency loss to step up to 110V, step back down to 5V.
|
| Having fitted out an RV though, it was nice to find lots of 12V
| appliances -- they could be run into a small 12V fuse block and
| the fuse block wired directly to a 12V "house" battery.
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