[time-nuts] Active LF Antennas
alan.melia at btinternet.com
Fri Jul 20 04:56:12 EDT 2007
Hi John, I think Lyle Kohler K0LER (?) has a version with the J310 on his
site. I have seen cases were J310s were placed in paralled to get better IMD
performance and maybe lower noise but that is not a problem at LF. They do
work well but like all voltage probe antennas need mounting high for best
performance. Another fairly popular antenna in the LF field is a circuit by
Roelof Bakker PA0RDT where the whip is replaced by a square inch of PCB pad.
This has proved exceptionally good in some noisy urban appartments and hotel
rooms mounted out off the balcony on a length of cane.
----- Original Message -----
From: John Miles <jmiles at pop.net>
To: Discussion of precise time and frequency measurement
<time-nuts at febo.com>
Sent: 20 July 2007 04:55
Subject: Re: [time-nuts] Active LF Antennas
> > Since the article and FAQ on the AMRAD site were
> > written, the split bobbin transformer is has become
> > available from Digi-Key. You don't have to special
> > order it.
> I was glad I ordered 10 of the Crystalonics JFETs for that project. Four
> them were defective as delivered (D-S short). You can save some bucks by
> going the J310 route first and upgrading to the CP666 only if you actually
> have IMD problems.
> -- john, KE5FX
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