End fed half wave qrp tuner

This was originally posted in my 'News and Views' section but is more relevant here I think....

I'm away with work for a week soon and to fill the evenings I'm taking the HB-1A with me. I needed a decent portable antenna and decided my older attempts were not very good so I needed a simple solution.

I opted for the End Fed Half Wave or EFHW antenna with a simple tuner that I can throw out of a window or use a 7m pole to support it. The tuner is taken from one of many designs on the internet and initial tests are very promising - on receive it is 3 S points better than my SRC-80 vertical (measured on my IC718 at 14 MHz) - an almost amazing 9dB! Now I know that's not gain over a dipole but over a significant indication of how poor the efficiency of the the SRC-80 is on 20m.

Cost less than 5GBP and for QRP it will do brilliantly - used it a few times and it works very well for me.

I forgot to write it on the schematic below but the turns are, starting from the antenna: 4 turns - tap - 24 turns. Count turns as the number of passes through the T50-2 ferrite core. A T50-2 may not be the best choice - possibly a 6 mix - yellow may be better.