[Elecraft] K3 Audio routing question

[Tom W8JI]

Hi David,

The Beverage and the vertical are both vertically polarized.

A single vertical is a very broad pattern with much less directivity than a 
Beverage. Since for receiving signal-to-noise is closely tied to directive 
pattern and not gain or antenna type, the vertical will have significantly 
less signal-to-noise ratio.

By mixing them both in one channel the beverage is really being phased 
against the vertical, and this will almost certainly be better than the 
vertical alone. Anything quieter (more directive) mixed in would improve the 
poor S/N of the vertical. This is because the combination of the vertical 
and Beverage is more directional than the vertical alone, so being more 
directional it has to be quieter.

I have no doubt the improvement seen by mixing the two is very real, but it 
would be better accomplished by using a noise canceller or phasing unit that 
allows adjustment of phase and levels, rather than random phase and level 
mixing.

I'm not opposed in the least to having an ability to mix the main and sub 
channels at the audio output in diversity mode. Even though it is not 
diversity, it could have some uses for some people. For example, it could be 
used when receiving multiple directions on SSB. It would not be good for 
phasing two antennas, because the K3 slowly rotates phase shift between main 
and sub as the dial is rotated to new frequencies. It would be better to use 
a noise canceller to do that in front of the receivers if the receivers are 
not being used for split directions.

I just strongly feel if allowed it should be something that can be locked 
out to prevent it from accidentally being applied to a system that is true 
diversity, since it would hurt that system. It could help people wanting to 
receive different directions at the same time using common bandwidths and 
other settings between both channels. maybe it is useful, but just under a 
different name (not in diversity) and way to activate.


> What you are trying to achieve is a (rather expensive) implementation of
>  a, single, non-steerable, phased array antenna.

It steers when the dial is turned, because main to sub phase rotates to a 
new difference as the dial is turned.

If there really is no
> phase difference, you've effectively synthesised a diagonally polarized
> antenna (although I can't work out why your signal polarisations should
> only occupy one quadrant).  You don't have a diversity system.  You
> could achieve the same effect by summing at the input frequency after a
> buffer/pre-amplifier.

Both a Beverage and vertical are vertically polarized. It would not be 
diagonal polarization in most directions, it would mostly be vertical in any 
phase combination since both antennas primarily have vertical response.

73 Tom