[Milsurplus] Ferrite Loop Antennas

[Brooke Clarke]

Hi John:

Yes, for LORAN-C it must NOT be reasonant. Those pulses take up a lot of 
bandwidth.  See: http://www.prc68.com/I/Images/Da100nf.GIF

But for a narrow band VLF signal you could add a bunch of caps in the radio 
room (the capacity of the coax would be small by comparison.

An improvement would be to change from a square to a hex or octagon and space 
the wires to raise the Q.

Have Fun,

Brooke Clarke
http://www.PRC68.com
http://www.precisionclock.com
http://www.prc68.com/I/WebCam2.shtml 24/7 Sky-Weather-Astronomy Cam


J Forster wrote:
> The loop I'm using is not resonant. I figured that would not be a good thing for
> LORAN, since it's a pulsed signal. The last thing I wanted was a bunch of ringing.
> As I remember, I designed the loop to look like roughly 50 ohms at 100 KHz...  the
> LORAN pulse frequency.
> 
> Best,
> -John
> 
> 
> 
> 
> Brooke Clarke wrote:
> 
> 
>>Hi Hue:
>>
>>They have small effective areas so are not optimal for weak signals.
>>
>>The attic antenna descrebed by J Forster sounds good.  It might be improved by
>>spacing the wires from each other about one wire diameter to lower self
>>capacity.  Reasonating would give you a nice high Q antenna.  A problem might
>>be the nulls.
>>
>>Have Fun,
>>Brooke Clarke
> 
>