[aprssig] Options for robust digipeaters

[Curt Mills]

This doesn't directly answer the questions but should apply:

A buddy of mine has been putting Rpi-4 systems onto mountaintops for
digipeaters, running Raspian Linux and SVXlink. Before you guys wince
and think "I wouldn't use an Rpi for that, they're not reliable
enough!"... I had the same thoughts initially.

The keys are:

- Buy very good and fast SDcards which are much larger than what you
need (spreads the writes across the card). Like 32 or 64 GB cards that
are name brand and fast.

- Use an Rpi UPS board that can control the reset pin.

- Set up scripts that take down the Rpi nicely when the UPS runs out.

- My buddy designed an Rpi board which controls two radios (with a
soundcard on there of course and PTT circuitry). He orders/builds more
as he needs them, he doesn't market or sell them.

He started deploying with earlier Rpi's and in fact one mountaintop
site is still running an earlier Rpi, like maybe a 2? That one will
get replaced with an Rpi4 when things warm up again here and he can
get to the mountaintop.

Some of these sites have RF links to other repeaters, a bunch have
internet links, some of those via HamWAN (another subject entirely).
The system works great, and he can adjust the audio in/out of each
radio remotely.

Anyway, that's one example of a H/W setup that could easily run
Direwolf instead of SVXlink and do what you're asking, 1200-baud-wise.
As far as 9600 baud you might need to do some experimentation to
figure that out.

Commercial Rpi radio-control boards (not what my buddy is using, but
nice boards nevertheless) are available, like the DRAWS boards from
Northwest Digital.

He says he's using Sandisk high-endurance 32GB SDcards now, but may go
to USB 3 SSD in the future. If he goes to those he may skip the UPS
board.


On Mon, Feb 8, 2021 at 1:25 PM Jim (List) <jim.list at stuckinthemud.org> wrote:
>
> Hi,
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> I’m looking for advice on current offering for a robust, field-deployable digipeater TNC/modem.
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> Over the years my go-to device has been the KPC-3+, mainly because when I started out with APRS the sound-modem stuff was rubbish and not easily deployed in the field without needing to be tweaked / set up each time. The KPC-3+ is bomb-proof, out-performs most other hardware, low power and just works (save for the known buffer/timing issues, but they were solved in v9.1). I’ve never had one fail in 25 years (and I’ve had wide-area event systems deployed with a dozen of them spread around the hills!).
>
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> The world has moved on and sound-modem stuff is now very good, so looking at what options there are for something that has multi-functionality - i.e. can be used at a centre or in a mobile for situation awareness, perhaps over LAN/Wi-Fi with an appropriate tablet/computer, used as an iGate, as well as “black boxed” with a radio for the hilltop where it can be just switched on and left by someone without any ARPS / computer knowledge.
>
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> Units that would reliably handle 9600 would also be useful. Again 25 years ago that was a problem, but radios from the “big three” (and I think some others) have the appropriate connections.
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> So, any recommendations / thoughts?
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> Jim
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--
Curt, WE7U        http://xastir.org        http://www.sarguydigital.com