[Elecraft] K3: Optimizing filter offsets for SSB TX and RX

[Joe Subich, W4TV]

If you crank in an offset with the 8 pole filters be sure 
you test it with BOTH USB and LSB.  An offset that enhances 
low frequency response in USB will reduce the LF response in 
LSB (enhance high frequency response) and vice versa. 

73, 

   ... Joe, W4TV 
 



> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net 
> [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of KM5Q
> Sent: Sunday, April 12, 2009 5:28 PM
> To: elecraft at mailman.qth.net
> Subject: [Elecraft] K3: Optimizing filter offsets for SSB TX and RX
> 
> 
> Continued from:   [CQ-Contest] SOME THOUGHTS ON USING THE K3 ON SSB
> 
> Reading these messages, I decided I should try adjusting the offset  
> for my 2.8 8-pole filter from the normal 0. I have been getting good  
> audio reports, but not "excellent".
> 
> Listening during adjustment, I found that as I reached -.20 
> some high  
> harshness was reduced. I thought that would be good, as I often find  
> myself cutting back the HI passband to get a similar effect. Then I  
> got on the Sunday Elecraft SSB Net. I couldn't get many opinions  
> because propagation  was poor, but I had Phil NS7P give me his  
> opinion. He reported the least distortion around offset -.20, and  
> clearly an improvement over the 0 setting. So that's where I 
> have it.  
> It's an easy test to make, since you can transmit with the CONFIG  
> window open.
> 
> Ever curious, I thought to play with my 2.1 filter offset (just for  
> receiving of course). I never liked listening to SSB with it because  
> the highs sounded harsh. As I turned it from the normal 0, 
> down past -. 
> 20, it started to sound better. I preferred around -.40 until I  
> checked it on a weak CW signal. It was making it weaker in 
> comparison  
> with the other filters. So I compromised and set it at -.27. 
> I'm happy  
> with that!
> 
> I think this is a good discovery! Maybe it's something the factory  
> should look into?
> 
> Windy KM5Q
> K3 #764
> 
> 
> Bill W4ZV wrote:
> > After extensive experiments with tx audio settings in pursuit of
> > "perfect
> > audio" for my purposes - dxing on 80m - I came to the conclusion  
> > that for my
> > voice with the HC-4, an offset of -0.07 with the 2.8 kHz 
> filter was  
> > about
> > right.
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