[Elecraft] K3: listening to both rcvrs

[Joe Subich, W4TV]

Jim, 

Unless one is using diversity with phase locked signals, adding 
the uncorrelated noise from one receiver to the signal from the 
other receiver reduces the overall s/n.  While you may think my 
use of the term "pollution" is unnecessarily negative, it is an 
accurate description.  

Assuming equal volume settings and equal bandwidths in the two
receivers, the S/N will degrade by 6 dB (twice the noise voltage). 
If one is listening to a desired DX station with a low noise 
antenna and the pile-up with a wider filter and a noisy transmit 
antenna, the S/N will be degraded even more.  

The K3 receivers are better isolated that other "dual receiver" 
transceivers.  It would be a shame to degrade S/N by adding a 
mix control when it is relatively easy to do so externally or 
those who don't mind the hit in S/N. 

73, 

   ... Joe, W4TV 
 



> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net 
> [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Dr. 
> James C. Garland
> Sent: Sunday, November 16, 2008 12:19 PM
> To: elecraft at mailman.qth.net
> Subject: RE: [Elecraft] K3: listening to both rcvrs
> 
> 
> Joe,
> Your comment strikes me as unnecessarily negative. (Pollute? 
> Crosstalk?)  I thought Fred's suggestion, coming as it does 
> from a very experienced CW contester, makes a lot of sense.
> 
> 73,
> 
> Jim W8ZR
> 
> > -----Original Message-----
> > From: elecraft-bounces at mailman.qth.net [mailto:elecraft- 
> > bounces at mailman.qth.net] On Behalf Of Joe Subich, W4TV
> > Sent: Sunday, November 16, 2008 10:09 AM
> > To: 'cloud runner'; 'Elecraft Reflector'
> > Subject: RE: [Elecraft] K3: listening to both rcvrs
> > 
> > 
> > If you must pollute the audio from one receiver with audio from the 
> > other receiver, add a 5 to 10K pot between the tip and the ring of 
> > your headphones and adjust it for the level of pollution you need.
> > 
> > There is no need for Wayne (or probably Lyle) to design 
> crosstalk into 
> > the DSP process.
> > 
> > 73,
> > 
> >    ... Joe, W4TV
> > 
> > 
> > 
> > 
> > > -----Original Message-----
> > > From: elecraft-bounces at mailman.qth.net 
> > > [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of 
> cloud runner
> > > Sent: Sunday, November 16, 2008 11:03 AM
> > > To: elecraft at mailman.qth.net
> > > Subject: [Elecraft] K3: listening to both rcvrs
> > >
> > >
> > > for what it may be worth...
> > >
> > > For my pair-of-K2's in SO2R, I have routed the audio in 
> such a way 
> > > that I have a balance control with the audio from the two 
> radios.  I 
> > > call it a mixing control.  I find that "optimum" is achieved when 
> > > the full strength audio is in one ear, and that same audio is 
> > > present, but weak in the other ear.  I reason that when the audio 
> > > goes to one ear only, the content must get to the other 
> hemisphere 
> > > of the brain within brain circuitry.  When it is routed to both 
> > > ears, now both hemispheres get the information for 
> interpretation at 
> > > the same time.  Making it strong in one ear and weak in the
> > > other, reversed for the other channel, lets me know which
> > > rcvr I am hearing, while brain interpretation is at full speed.
> > >
> > > and so, Wayne...
> > >
> > > I think that there must be a firmware way either by routing to a 
> > > panel pot, or probably more simply in a menu, by which 
> the operator 
> > > can select either complete channel isolation, or both channels to 
> > > both ears, but with one ear X DB down from the other.  (I 
> can't say 
> > > how much down is best,but I find that it is enough when I 
> can barely 
> > > notice it.  All of a sudden copy is MUCH easier).  Give 
> it a thought 
> > > because of the above, I, at least, am quite convinced 
> after a lot of
> > > usage with a pair of K2's in SO2R, that is a much better
> > > arrangement for copying CW from the two channels.
> > >
> > > with much appreciation for this fine radio,
> > >
> > > 73,  Fd - KT5X
> > >
> > > K2 # 0700
> > > K3 # 0144
> > >
> > 
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