[aprssig] Options for robust digipeaters

[Curt Mills]

Forgot one other: He moves a bunch of things to a tmpfs directory in
memory to save on writes to the card.

I personally would also do some Linux tweaks to reduce writes to the
SDcard, like I do for SSD drives. I don't know if my friend does that.

On Mon, Feb 8, 2021 at 2:28 PM Curt Mills <curt.we7u at gmail.com> wrote:
>
> 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,
> >
> >
> >
> > I’m looking for advice on current offering for a robust, field-deployable digipeater TNC/modem.
> >
> >
> >
> > 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!).
> >
> >
> >
> > 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.
> >
> >
> >
> > 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.
> >
> >
> >
> > So, any recommendations / thoughts?
> >
> >
> >
> >
> >
> >
> >
> > Jim
> >
> >
> >
> >
> >
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>
>
> --
> Curt, WE7U        http://xastir.org        http://www.sarguydigital.com



-- 
Curt, WE7U        http://xastir.org        http://www.sarguydigital.com