Topband: Fw: Diversity

[k3ky at erols.com]

On 14 Apr 2004 at 20:53, john battin wrote:
 
> Subject: Diversity
>  
> Most of the time I listen to the vertical array with one receiver and the beverages with the other. Diversity is almost always distinct advantage. I would not live with out it. When it does not work, it is usually that the signal from one of the antennas is too poor to add anything but noise.
> John K9DX
>
This has been my experience as well. My FT-1000D does antenna
diversity with a common VFO running both receivers, and the two
signals are entirely separate from antennas all the way through to
the stereo audio amp and stereo phones. The characteristics of
the two receivers are significantly different. The sub-rx is "OK"
but not as good as the main-rx. Probably there would be phase
differences in the IF local oscillators. Nonetheless, diversity
mode almost always yields at least some small improvement.
In some cases, the improvement in intelligibility is significant.
Only rarely have I seen diversity actually hurt intelligibility,
where added noise overwhelms any other gains.* It seems to
be sufficient to set both receivers to have similar IF and audio
bandwidth. The ear-brain filter takes over from there and is no
doubt always a part of the overall system gains, if any.

There is one intangible, which is hard to quantify, but I can
say that diversity reception is something which simply must
be experienced personally before it can truly be appreciated.
Even in a 'no gain' situation, I find diversity to be compellingly
preferable. Once you have been exposed to true diversity
reception, even after just a few minutes of comparison,
monaural operation will forever more sound 'muffled' to you
when compared to binaural ('stereo'). If you have the choice,
you will probably nearly always choose stereo.
73, David K3KY

* Both antennas must be receiving some discernable
signal. It is pointless to add another antenna if it is not
picking up signal.