[time-nuts] LORAN-C antenna

Didier Juges didier at cox.net
Wed Nov 14 08:13:14 EST 2007


OK, thanks for the useful information . I thought you might have resonated
the loop to get some filtering ahead of the preamp, which is what I would
have done, not knowing any better...

If I use a ferrite rod, it will most likely have too much stray capacitance
to be broad band, but the air loop as you have done is not too big, so I may
try both.

Looking at the spectrum analyzer plots, it seems I do not have too many
competing signals around here, so on the one hand, a broad band loop should
work nicely, on the other hand, there is no other signal around I am
interested in, so I may tune the loop and get some filtering.

Thanks,

Didier

> -----Original Message-----
> From: time-nuts-bounces at febo.com 
> [mailto:time-nuts-bounces at febo.com] On Behalf Of Poul-Henning Kamp
> Sent: Wednesday, November 14, 2007 2:25 AM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] LORAN-C antenna
> 
> A loop antenna is more or less flat until the stray 
> capacitance of the loop windings take it down.
> 
> I put a low-pass filter which cuts around 300-500 kHz on this 
> one, because I have a MW transmitter at 1062 kHz only 30 km 
> from my house.
> 
> And that is the other good reason to use a loop: you can null 
> out one strong signal with the orientation.
> 
> -- 
> Poul-Henning Kamp




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