Hi Roelof, VLF,
Yes, we (and others) arrived there on 137kHz and above. But it is so hard to
belive that this is optimal even in the 33km band. Maybe the optimum C is not a
function of the frequency, if discussing an optimal SNR.
But you know i am rather a practical instead of a theoretical OM ;-) Therefore
i asked if someone has checked this before on VLF. I also know the equivalent
circuit of that probe and the FET input, out of Rs and Cs but anyway ;-)
With a stronger input signal and same SNR there could be a benefit to
unsensitive receivers as well (as you mentioned) as long as the input stage is
not overdriven...
Paul, have you a website where your RX equipment is shown? The antenna and it's
environment, cables and so on? Maybe the preamt with the LT1028 and so on?
73, Stefan
________________________________
Von: [email protected] im Auftrag von Roelof Bakker
Gesendet: Mi 24.03.2010 22:40
An: [email protected]
Betreff: Re: AW: LF: Re: Mini-Whip
Hello Stefan,
Just like you have reported some time ago, I have done tests to establish
the best SNR for a whip antenna at LF in regard to the minimum length. I
arrived at the same length as you did at 137 kHz: 30 cm. A longer antenna
did improve the signal strength, but not the SNR. The capacitive probe is
equivalent to a 30 cm whip.
I can't see a reason why the SNR should change with frequency, but I will
test it nevertheless.
73,
Roelof, pa0rdt
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