[OZAPRS] Raspbery Pi (RPi) Gateway

[vk2ycj at bravo.net.au]

Ray,

A nice story and an encouraging project !


Jamie VK2YCJ


> All,
>
> For somewhere around two years or so I'd been searching for a computer
> with low input energy requirements to use as a gateway machine to
> replace a conventional desktop system. And then I moved location quite
> suddenly which threw my plans into chaos. I'm now in a position to
> reestablish gateway facilities with 2m, 30m and satgate facilities, as
> per my original gateway.
>
> Although I'd looked at the RPi (http://www.raspberrypi.org/) as a
> suitable computer, it was Bernard F6BVP (maintainer of xfbb and fpac)
> reporting that he had compiled a kernel with ax25 support that got me
> really interested. The latest Debian kernel -
> 2012-08-16-wheezy-raspbian.img -has kernel ax25 included.
>
> The RPi is a single board computer using a 700MHz ARM processor. It runs
> from a single 5V supply. The PCB is about the size of a credit card, has
> HDMI and composite video out, audio out, one ethernet port and 2 x USB
> ports. They are available from Element 14 (rebadged Farnell) and RS
> Components for about $38. See the wiki at
> http://en.wikipedia.org/wiki/Raspberry_Pi
>
> My original intent was to run soundmodem to provide two 1k2 ports but I
> found soundmodem unstable and unpredictable on both the RPi and my
> desktop environment. In addition, the RPi failed to boot with a Sound
> Blaster Play USB dongle plugged in. The dongle is supposed to work OOTB
> on the RPi. Other users have reported similar boot problems.
>
> Given that I still have a number of MFJ1270B TNCs I decided that a
> hardware approach might be more feasible in the short term. They can
> always be replaced by more efficient newer options (TNCX, TT4, etc) in
> the fullness of time. In order to run hardware TNCs I needed RS232 ports
> so a USB/RS232 adapter was needed. A recommendation from the xastir
> mailing list suggested a 4 port FTDI adaptor from DigiKey, at this
> address -
> http://www.digikey.com/product-detail/en/USB-COM232-PLUS4/768-1034-ND/2139296
> The unit cost about $76 with freight and arrived in four days from the
> US. I plugged it into the RPi and it worked OOTB. The adapter doesn't
> have a case, but neither does the RPi.
>
> Because the gateway system will be away from the house I needed wifi for
> Internet access - too difficult to get Cat5 to the shed. I bought a
> TP-LINK TL-WN721N USB dongle and it almost worked OOTB. I needed to
> install wicd to be able to configure it but it works a treat. In the end
> I decided to use my Realtek 8189 equivalent wifi modem for the RPi
> because it has an external antenna. It just worked OOTB as well.
>
> The RPi reliably boots with both the USB/RS232 adapter and the wifi
> dongle connected.
>
> The software I had previously used for the gateway machine is xastir.
> It's always done the job and it's stable. The RPi will run headless and
> even though I don't "really" need the graphical display of xastir I was
> intent on giving it a try. Although there is now a deb package for
> xastir (with a current version), I opted to compile xastir on the RPi. I
> had already compiled the kernel ax25 surces for libax25, ax25apps and
> ax25tools.
>
> Although the Raspian distribution is based on Debian Wheezy, not all
> packages are available for the ARM processor - yet. This led to some
> dependency conflicts that I eventually resolved by seeing what libraries
> had been used in the deb package. I finally managed to compile xastir
> with all options except festival sound, which I don't need. When I
> booted xastir it reported being unable to find libax25.so.1, even though
> it exists in /usr/local/lib. For whatever reason, xastir was looking in
> /usr/lib so I created a symlink - problem solved.
>
> Xastir is understandably slow when loading raster maps (but lots faster
> than xastir 1.4 on a P166 machine some years ago!). For my trial I use
> just one map so speed is not an issue. A final installation may have no
> map loaded. Xastir is now running as vk2tv-4 but without radio ports at
> this stage until I assess reliability. I don't expect any issues.
>
> During my enquiries on the xastir mailing list it was suggested that
> xastir is not ideal for a gateway machine (read that previously) and
> that I should try aprx which works in a non-graphical environment. I've
> also compiled a deb package for the ARM processor and it installed just
> fine. aprx has some very flexible configuration options and it reports
> lots of statistics on channel usage, etc, as telemetry beacons. It
> appears worthy of a trial run s that's my next project.
>
> My goal is to have a solar powered gateway and the RPi has taken me a
> lot closer to that goal.
>
> Ray vk2tv
>
>
>
>
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