Hello Stefan,
there is a easy way to check if you have too much attenuation or not:
Tune the RX to an unused freq (only noise/QRN) and disconnect the
antenna; if you can hear the difference between antenna / no antenna
then attenuation is not too much.
With a 11m high / 25m long lazy-L antenna at a quiet location I could
add 40dB attenuation and still hear the noise increasing when
connecting the antenna.
I guess with a kite-antenna 50 to 60dB might be a good value.
Of course it all depends also on the RX used, I use a Kenwood TS440
that seems to be sensitive at LF.
73, Rik ON7YD - OR7T
Quoting Stefan Schäfer <[email protected]>:
Hi Rik es tnx for your answer.
In the first QSOs from /p I used the TX antenna. I quickly saw that
SNR is much better with a 6dB attenuator. In the last activity I
even used 20dB. But the SNR of the small active antenna is
definitely better. Perhaps it is a good idea to try even more
attenuation, tnx, I will try that!
On my QTH at my parents (2003/2004) I also used the TX antenna but
it was much smaller. This antenna was more suitable for RX although
the actual QTH is apart from any house in a region of some 100s
meters...
73, Stefan
-----Ursprüngliche Nachricht-----
Von: [email protected]
[mailto:[email protected]] Im Auftrag von Rik Strobbe
Gesendet: Samstag, 26. Dezember 2009 23:29
An: [email protected]
Betreff: Re: LF: Influence of a TX antenna to a small rx antenna
Hello Stefan,
why not use the "big" TX antenna also for RX. With a sufficient
atenuator of course.
On 137kHz I alway used my TX antenna for RX, but a 40dB attenuator was
required to avoid overload at the RX.
73, Rik ON7YD
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