Re: general coverge rx on qsx


Erik Kaashoek
 

The ATU comes in various designs. L-C-L or C-L-C and they either act as a low pass filter (when the C go to ground) or a high pass filter (when the L go to ground) but never as a narrow BPF
But your antenna is a (multi) BPF!!!!
Using a half size g5rv and the QRP-Labs receiver I am able to receive FT8 (in the middle of a city) from literally  ALL over the world on 40m and 20m.
The half size g5rv only needs a little bit of tuning. see attached measurement. Maybe if I shorten the dipole it could get even a bit better.


When using my 1 Watt transmitter on the half size G5RV I have a switchable low pass filter for 20m and 30m/40m and that is all I use. No BPF for FT8 as the antenna is already a good BPF!!

--
Erik, PD0EK

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