This project might be of interest to some SOTA operators.

I wanted to see if I could make a field companion Raspberry Pi for Data modes - I would never lug my laptop into the bush.


  • raspberry pi 3 with inbuilt wifi chip
  • USB GPS dongle
  • USB sound card
  • ZLP USB radio interface


  • WSJT-X on RC1.9 for FT8 etc
  • Fldigi
  • Winlink using PAT - telnet only at this stage
  • APRS via Xastir and Direwolf
  • Logging using CQRLog - issues with database - working on that
  • GPS updates onboard time - needed for Data modes and logging as well as GPS for APRS

How do you use it?
Well when the Pi is near a wifi network it knows it connects when it is not - say on your favourite summit - it creates a hotspot allowing headless control by any VNC device - tablet, phone etc.

Some pictures:

VK1MIC. com


Wonderful wee thing the Pi when you need a bit of embedded ‘smarts’.

I’ve been using this setup for anywhere in the world spotting since 2014.

That’s a Pi B+ on the left and an Iridium SBD modem on the right. The Pi has a Wifi dongle and runs as an access point. Connect to the web server in the Pi with your phone, enter the spot on the web page and hit spot. 22-30secs later the spot appears on SOTAwatch thanks to the Iridium satellite network.

I did look at updating it to use a Pi ZeroW as that would fit in the box holding the modem and would make the other box obsolete. It would be smaller and weigh less. But I’d have nothing to do with the Pi B+ then and it’s paid for so I can’t waste it! :slight_smile:

The Turnigy 5V PSU runs from 7-24V and generates no noise on HF. You can place the setup right by the SOTA antennas and there’s no QRM at all. Which is nice.


Wow. Sounds lovely. Wonder what the $$ on running the iridium is? Same as say a satphone? Just without the outlay of hardware

There is a monthly charge for service and using the airtime providers services (i.e. their web/mail servers that you send and receive from) then there is a charge for every 50bytes sent or received. The only thing which is free is syncing to the satellite and getting the current signal strength!

The monthly charge has just gone up for the 1st time in 4 years and I can’t remember exactly but if you work on AU$22 / month and ontop of that you pay in 50bytes chunks at AU 24c per 50bytes. So it’s not exactly cheap compared to modern mobile phone contracts. You can buy data credits and they last till you use them. The monthly airtime is bustable, i.e. you can buy a month’s airtime then not buy anymore for 6 months, you don’t have to maintain constant access. But it works absolutely everywhere .

Had a Raspberry Pi 3B for Christmas. I’m sure it’ll have lots of uses when I can figure out what do do with it… Unfortunately if someone says Python to me I think more of lumberjacks, cheese and expired Norwegian Blues than an interpreted high-level programming language :-s

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I’ve kicked the tires on using Arduinos and RPis to “enhance” my SOTA experience but in general felt the hassle factor really didn’t justify it.

I thought it would be ”cool” to use an Arduino to collect UV levels, ambient temperature and barometric pressure on the ascent (the Western US can be quite human hostile). Prototyped something and “dogs dinner” is a generous term to describe the end result.

Then onto the RPi. I acquired the 7” RPi foundation touchscreen and mated it to a nice body with the intent of running FT8. WsJt-x required a larger screen resolution and so usability killed that project. Which wasn’t all bad as my mountaintop FT8 activations using a windows tablet showed me that muscle counts.

I did get Fldigi running on my RPi 7” but PSK 31 seemed to hit or miss for SOTA.

I even acquired the smallest keyboard known to man to help reduce weight…

Yeah I have a couple of pis around the house - 2 are my media players and one is my wifi garage door remote.

For radio I have one as an APRS RX Igate (can TX but its not super reliable as it is connected to a UV5R which doesnt do vox really well) and now portable.

The difference I would say for you @W6PNG is that I carry an android tablet now for logging with @VK3ZPF logging software - the additional kit for me would be the audio interface and the pi. The rest is already in the bag.


post has been updated on VK1MIC.com with lessons learnt after a month of use.


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