On 2/23/2012 2:30 PM, Stefan Schäfer wrote:
Hi Alberto,
That looks fine. I'm glad to get a report from you, thank you.
How long was that wire and was it in the house or outside? :-)
Hi Stefan,
oh, that wire was just a dipole for the 40m band, directly
connected to the receiver, without any form of tuning for the
137kHz band.
Signals are low, but so also is the noise... :-)
Often is advantageous to have a not so high gain antenna... the
S/N ratio can improve... not always, but sometimes yes.
That dipole is low in height. Actually it is an inverted V, with
the apex at 10m from the ground.
For the LF band I have also a mini whip, temporarily out of
service, as I used the coax feeding it for some tests of a
differential active antenna,
with two beer cans spaced abt 1.5m connected to the differential
inputs of a high impedance amplifier. It works quite well, as it
does
not need to be referred to a ground potential, but maybe I have to
change the schematic of that transimpedance amplifier, as it
exhibits more intermodulation that I thought it should have....
73 Alberto I2PHD
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