[OZAPRS] Considerations For Setting Up an igate (RasPi)

Marcus B mrmabs at gmail.com
Sun Dec 15 23:58:00 AEDT 2019

Hey all,

I had a thought bubble, probably unlikely to have time to pull this off,
but you never know. So right now we'll treat this as an intellectual
exercise, with a chance it might actually happen.

A couple of months ago travelling through northern Victoria I noticed a
lack of coverage (between Robinvale & Shepparton), and thought about
setting up a small igate at a relative's place in Cohuna. If I did this I
would be doing it just after the new year, and I won't be able to visit to
maintain it potentially for 10 to 24 months. It's also unlikely that I
would go to the trouble to open a remote port to ssh in, so must be
reliable hardware and software wise. I have access to WiFi.

What I have today: Pi Zero W with a protoboard to connect TTL serial to a
dorji board + LDO regulator, and a usb sound card. Also have 4.5m Jaycar
telescopic mast and I could put a DIY 1/4 wave on top. Also, the further
away from the house, the better, so that means, if possible, run off its
own power. Maybe a 12V 12A SLA & 10W or 18W solar panel will do the job?

I have not done much TX testing, RX seems to work fine.

It's pretty flat out there, so at 4.5m above ground, I may expect about
5-10km coverage (running on HeyWhatsThat.com confirms that it would be a
very patchy to the west, and then there's the trees, and house roofs), and
unlikely to hear anything on 145.175 unless some serious tropo comes in. I
can also look up how to get up an igate with direwolf easy enough. In
reality I might be lucky to hear one station a month given the reports I
have seen for VK3RMK-1.

How should I set this up, purely as an RX only igate? I have also
considered just getting it to TX occasionally (30mins?) just to say hello,
but at 1W eh... At this location in about 1996 I was able to have a
scratchy QSO on VK3RMM on 5W (HT) using a CFA 160MHz 1/4 wave at 10m; so
it's not all doom and gloom. That 10m was a solid steel pipe and it is
looooong gone.

With all that, what could I do to make this set up better? Best bang for
buck? (Obviously the dorji modules are pretty low quality.) Location is
pretty much fixed. What about to improve reliability? Best ways to protect
from heat (does it need it)? What sort of protection (power, temperature,
etc...) should I consider?

What else am I not thinking about?

Maybe, alternatively, I could make a 2m WSPR beacon on a Pi with filter and
attach a GPS :P

vk3tst / vk5wtf
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