For many years (almost 20) I have been pointing out that the band conditions
here in Europe are much more severe than in the states, especially on 40m.
Many radios that behave like a super trooper in the states fall flat on
their faces here in EU, due to total front-end overload.
I have also been saying for 2+ years now that I will buy an SDR radio and
connect it to my Eagle as a panadapter.
I FINALLY bit the bullet and bought an SDRplay RSP2, SDR receiver this week.
The first acid test was to try the radio at night on 40m.
The antenna used is an Aerial-51 Model 807 - 80m OCF Dipole.
Its 40m radiation pattern is like a 4-leaf clover, so it pulls in good
signal strength from most directions.
Assuming there would be some front-end overload (intermodulation), I
connected my home brew "tunable" 40m preselector which I built in 1977 while
working in the lab at Rhode und Schwarz in Berlin. It was designed by DL7AV
and has about 6dB insertion loss. Its 3dB bandwidth is about 30 kHz and its
ultimate attenuation of 35+dB is reached about 50 or 60 kHz away. I
measured it exactly in 1977 and recorded it onto a piece of paper which I
haven't seen for many years now. In any case, it is an outstanding
preselector, albeit only for 40m.
For use on other bands, I added a 20 dB attenuator. Of course I only used
it for 80m and 40m, not for the high bands.
On my web you will find a short video showing the recorded results.
Once I get familiar with this radio and the software, I will try to optimize
the settings and run this test again.
See: http://www.dj0ip.de/sdrplay-ota/
73
Rick, DJ0IP
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