[Lowfer] K9AY

[Bill Ashlock]

>but it is a very difficult thing to measure (the polar pattern) and I have not seen a good measurement
 
Hi again Alan,
 
Wonder if the antenna can be used as a transmitting antenna having the same pattern?? Of course the efficiency would not be good because of the high power loss in the resistor but this would allow easy mapping of the low angle signal strength and thus a polar pattern could be determined. 
 
This brings up another idea I've had for some time relative to TX loop pattern modification. I would think that by combining patterns from two different antennas there could be a gain in signal strength in a desired direction over a loop with a standard figure "8" pattern. This idea could be applied to simply reduce the portion of the magnetic field that penetrates the ground and causes Rac loss.
 
Bill> From: alan.melia at btinternet.com> To: lowfer at mailman.qth.net> Date: Thu, 15 Jan 2009 10:58:08 +0000> Subject: [Lowfer] K9AY> > Hi (I have changed the subject as it was getting away from the original> post)> > Hi Bill I think your "model" is viable there is just one point that worries> me about it. If it was to act like a loop and sense it should have a> substantial signal sensitivity from the side. The reports I have seen and> the experiements done by Finbar on NDBs sujject that this is not the polar> (azimuth) pattern that they produce......but it is a very difficult thing to> measure and I have not seen a good measurement. Another thought would be is> the signal sensitivity proportional to area regardless of shape as it would> be with a loop. In this case the directionality might degrade it there was> not a significant vertical component. I certainly know that "two turn"> versions are an advantage at LF ( Hartmutt uses one to brilliant effect),> and Finbar showed the sensitivity increased by tuning (at LF) without losing> the directional effect.> > I guess no one is "wrong" they are probably just different ways (analogies?)> for the same effect. This continues to be an interesting topic (to me anyway> :-)) ) There is definitely no doubt they work! Room for some more> experimental work ?? :-))> > Alan G3NYK> > _______________________________________________> >From the Lowfer mailing list> Send messages to: Lowfer at mailman.qth.net> To sub/unsub visit: http://mailman.qth.net/mailman/listinfo/lowfer
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