[TowerTalk] Antenna Interactions - Reradiated Noise?

David Gilbert xdavid at cis-broadband.com
Fri Jan 19 17:59:42 EST 2007



The receiving antennas typically used on 160m and 80m are not very 
efficient (they make poor transmitting antennas), but they have good 
directivity and therefore discriminate against noise coming from 
unwanted directions.  If the transmitting antenna is resonant and 
happens to be positioned near the front (its desired direction) of the 
receiving antenna being used at the time, it captures noise from all 
directions and re-radiates it to the receiving antenna, thereby 
defeating its directivity.

73,
Dave   AB7E


kd4e wrote:
> I read this on another list ...
>
> "It does reradiate enough noise, if not detuned,
> to mask weak signals on my receiving antennas ..."
>
> I have read of passive antennas used as passive
> repeaters, so it does make sense that such a thing
> could occur ... but under what sort of circumstances?
>
> Could we in some rare cases actually raise our
> local noise floor, or suffer such, due to new
> antennas or other metallic objects in the area
> of our antennas?
>
> Just curious ...
>
>   

-- 

Anything worth doing is worth doing to excess.



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