Soda Pop QRP transceiver

Back in 2017 Steve KD1JV announced the first of the Soda Pop rigs. The Soda Pop is single band transceiver but was capable of operating of a wide frequency range. So, following some discussion on the forum Steve include extra pads to allow for the use of band modules should any one like to go down that path.

The finished Multi Band Soda Pop
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Portable power options

Like most SOTA activators I started with a 3S style pack to power my radio’s. These packs are a great choice, affordable and light weight. They are however a little harder to pack and carry for aircraft travel and require a specialist (balance) charger when recharging thus adding bulk to any extended holiday plans including SOTA or Parks.

1500mAh LiFe 3S pack

Two things caused me to re-visit the options around battery packs, firstly the KX2 uses a 3 cell Li-ion pack which is difficult to locate an equivalent for in VK, and the failure of my 3S style pack.

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Miss Mosquita finished the build

I have now completed the build of my Miss Mosquita 3 a 40m CW transceiver.


I decided to mount all controls and connectors on the front as I feel this is a better configuration for a portable rig. The antenna connector was swapped to the RCA to save some internal space, and is reasonably common amongst qrp gear, so not too out of place.

The push button ‘f’ is for the freq-mite which announces the operating frequincy in morse code


Upper left is the Freq-Mite pcb, just below it is the Simple Keyer from QRP Kits with its Peizo mounted on the perf-board.

TX power, at 10.0v- 2.4W, 12.0v- 3.4W and 13.8v- 4.4W

Drift is around 180Hz in the first minute and a further 300 Hz by the 5min mark, it then settles down and is not noticable on all but the longer qso’s.

Tuning range, 6997 to 7046 KHz (49KHz) and quite linear over the full range.

A Small modification to my EMTECH ZM-2 ATU

With the current bad conditions the need to run 80m during the day for SOTA activations has caused me to visit antenna options that would allow me to run 80 with a “minimum” amount of wire.

My normal SOTA / WWFF antenna is an end fed of around 25m with a 6m counterpoise, this is then matched to 50 ohm using an external L Match. This configuration is fine on 40m and up, but is too close to a quarter wave length on 80m to match well. Continue reading