In the German QRPForum someone mentioned a group of QPR enthusiasts QRPGuys. They have some neat QRP kits - transceivers as well as antenna-tuners.

I gave these kits a try: QRPGuys Portable Tri-Band Vertical Antenna and the QRPGuys 40m-10m UnUnTenna Plus   

This post deals with the first one - the QRPGuys Portable Tri-Band Vertical Antenna.

This antenna tuner consists more or less of two switchable inductors:

(c) QRPguys

First I've build the antenna as described in the user guide

TriBand 1 IMG 1501 TriBand 2

Testing the antenna in my backyard shows a far too low resonance on all bands. The length of the vertical element is given with 5.18m or 17'. I had to shorten it to 4.90m to get a 1.4:1 SWR on 20m.

Switching L1 in series with the vertical element give also a very good SWR of 1.5:1 on 30m. But the 40m resonance was about 600kHz to low - so I removed 5 turns from L2 (the 40m inductor).

Now I have on all three bands a good SWR of 1.5:1 or less. For the radials I used four wires, each of 3.05m or 10' layed on the ground in a star pattern.

The antenna has her first mission behind. I've used her on the summit "Kaltes Feld" and she worked very well.

 

2014 CW (Morse Telegraphy) was added to the German Nationwide Inventory of Intangible Cultural Heritage.

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