One of the very exciting things of Amateur Radio are SOTA activities.


You have to climb up a mountain and operate a protable station for a few hours.


My SOTA Equipment is a lightweight one. Using QRP in CW mode with an FT-817 with about 2,5 W output.
Most important with such small power is a good antenna. After trying several dipoles with there disadvantage of fixing for monoband and the additional mechanical load to the center pole from the coax or 300 ohm feedline, I went back to the old Fuchs-Antenna. It is an halfwave allband high Z endfeed antenne, which needs no counterpoise!


Short Visualisation with an excel diagram showed that an overall length of around 20m would be good for 40m to 10m. Even 80m is possible if the antenna is loaded against a rather good counterpoise. Normally a 6-10m long fishing pole is used as a center support for the antenna wire. The near end is terminated at a small ATU at the transceiver site, the far end slopes down to about 1m above earth. To get n*lambda/2 situations for the WARC-Bands too, there are small bridges at the end to open. The bridges are easy to reach from the far end.


If each end of the Fuchsantenna is folded back, a very small footprint will be achieved.


My 40-10m SOTA Mini ATU follows the cuircuit diagram of the famous LDG Z-11 automatic tuner. But my small ATU is not constructed for 80m because there is less SOTA activity on this band.  For 80m a greater C1 (up to 250pF or so) would be necessary. To prevent static voltages reaching the transceiver, tnx OE6GWG, I used the highpass configuration insteed of the lowpass one of the Z-11. Used a perforated PCB and wired all without a deticated etched board. Used 6 similar but smaller cores, not the amidon one as the Z-11 and 0,5 CuL. The Z-11 is using eight T50-2 with 0,6 CuL and allowing 60W PEP or 30W CW. But my smaller toroids are good enough for my max. QRP power of 5 watt.

Mini ATU:

This is my present SOTA Equipment in a small Samsonite bag with nack strap.The whole setup with the antennawire, headset, keyer, ATU is in this bag. The weight is below 2 kg!


Using 2500mAh Sanyo Eneloop akkus inside the FT-817 allows headset SOTA operation in CW at 2,5W output for about 2h. Just the usual SOTA session.


The antennawire is insulated braid with an outer diameter of 1mm only. So no unnecessary weight at the top of my fishing pole!

I don´t  need a chair or table for the short SOTA activities anymore. I do left hand keying and writing with the right hand, just opposite to the picture, because did operate the shutter with right hand ;.))

This shows the previous setup in the plastic box. Now everything is in the small samsonite bag with the nack strap.