[time-nuts] LORAN-C antenna

[Dan Rae]

Didier Juges wrote:

>
>Is it possible to build a Loran antenna?
>  
>
Yes.

For my Austron 2100 I built an active ferrite rod antenna which works 
very well.  Much better than an active rod since by using the magnetic 
field component, it rejects a lot of the local interference (tv 
timebases and computer monitors etc.,) that the rod picks up.   I am 
several hundred miles from my nearest Loran station however, so the 
signal is not that strong...

I filled a ferrite rod (from an old BC receiver) with a bifilar winding 
of wire wrap wire, parallel C to resonate at 100 kHz and the center tap 
grounded.  This feeds the gates of a two FET push pull amp, the output 
of which is transformed into a medium / low impedance to feed the Rx.  
12 Volts DC power is multiplexed onto the coax feed line.  As is, it was 
too selective, but a 10 k Ohm R across the antenna rod seems to be 
enough damping for it to work well.

I also use a similar one for WWVB, but here you need all the selectivity 
you can get and it is in fact so selective that some temperature 
compensation was necessary. 

Not a major project, and it fits neatly into some bits of plastic 
plumbing, a lot smaller than any wire loop would be.

Dan
ac6ao