[K3} XFIL Offsets and Diversity

[Bill W4ZV]

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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[Joe Subich, W4TV-3]

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: [hidden email]
> [mailto:[hidden email]] On Behalf Of Bill Tippett
> Sent: Thursday, October 23, 2008 11:16 AM
> To: [hidden email]
> 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
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
>  http://mailman.qth.net/mailman/listinfo/elecraft   
>
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com

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