[A-DX] Unerwünschte Mischprodukte bei Wellbrook ALA1530

[Wilhelm Hombach <wh.bonn@xxxxxxxxxxxxxx>]

Hier geht es weiter mit der "Daily soap":

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Wilhelm,

The loop inductance is about 2.2uH. The loop is shunted by a low
impedance amplifier at HF, so any parallel resonance will be severely
damped.

You could also try putting a 100 Ohm resistor across the loop to
reduce the PD caused by the FM Tx.

The loop is the antenna i.e. it is not shielded.  The loop is balanced
to reject the local E Field.

Another idea; add a electro-static shield;  if you put the plastic
packaging ( 22mm x13mm) pipe insulation round the loop. Then you could
wrap aluminium foil around the insulation and connect this to the
feeder screen. Make sure that you have a gap in the shield at the top
of the loop.

73
Andrew
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Dear Andy,

thanks again. I will perform your advice as soon as the cold and snowy
weather will stop and I will have a chance to climb up the roof. First
I will try the 100 Ohm resistor as that will match to the aperiodic
design of the antenna.

To modify the antenna with the electric shield it would be interesting
to separate the loop from the amplifier. Is it possible to do this
without damage?

Greetings
Wilhelm

==========

Wilhelm,

You will damage the antenna if you try to remove the loop.
Btw, the loop design does work with an electro static screen.

73
Andrew

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