[Elecraft] [K3} XFIL Offsets and Diversity

[Joe Subich, W4TV]

Bill, 

Another point of reverence ...  

Main: 
> 2.8K -0.00 Hz
> 500  -0.80 Hz
> 250  -0.87 Hz

Sub: 
> 2.8K -0.00 Hz
> 500  -0.80 Hz

SSB/SSB and 500/500 Hz - no frequency/phase difference as expected. 
500/250 Hz - approximately 2 Hz warble.  

The 2 Hz warble is a  bit "odd" with speakers=2 but does not seem to 
be a problem with headphones.  The 2 Hz warble is a larger problem 
with fading signals than with steady ones. 

73, 

   ... Joe, W4TV 
   




> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net 
> [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Bill Tippett
> Sent: Thursday, October 23, 2008 11:16 AM
> To: elecraft at mailman.qth.net
> Subject: [Elecraft] [K3} XFIL Offsets and Diversity
> 
> 
> I decided to check the effect of different XFIL offsets on 
> Diversity and thought some of you might be interested:
> 
> XFIL/Offset:
> 
> Main
> 2.7k  -0.83
> 1.8k  -0.00
> 500   -0.78
> 200   -0.91
> 
> Sub
> 2.7k -0.83
> 500  -0.78
> 
> I fed my XG1 to ANT1, set both Main and Sub RXs to Main ANT1, 
> and then varied WIDTH to toggle the different filter combinations:
> 
> Main/Sub:
> 
> 2.7k/2.7k - No freq or phase difference (as expected)
> 1.8k/2.7k - ~2 Hz warble (probably not objectionable on SSB) 
> 500/500 - No freq or phase difference (as expected) 
> 200/500 - ~0.2 Hz warble (i.e. 1 cycle every ~5 seconds, not 
> objectionable on CW)
> 
> I've been using the latter combination recently and was 
> surprised it was not as noticeable as I expected.  Just 
> decided to check it and thought others might be interested.  
> I don't think my results would apply to everyone, but this 
> may mean having identical offsets is not as critical as I 
> once thought.
> 
> 73,  Bill  W4ZV
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