[Elecraft] Elecraft Digest, Vol 170, Issue 7

[John Perlick]

K3 vs S-Line

This is an interesting topic.  Sherwood has made distortion measurements on many many receivers.  As you see on his website, the K3 is far far better than the S-Line.  

The key measurements are dynamic range measurements—particularly with nearby signals.  The radio is limited at the low end by its noise floor (and because HF is so noisy you really done need super low noise floor).  But at the high end, the receiver is limited by distortion and blocking.  The K3 and, interestingly the KX3, are near the top of the list.  Far better than the old Collins rigs. 

I think what happens is we remember back in the 1960s when there were far fewer hams and that old 75A4 really sounded great!  I fully agree—these radios did sound great!  

But today there are twice as many hams crammed into the same bands and is can be really tough for receivers to discriminate without distorting.  

If you want to see what I mean, try using your 75S3C during a busy contest then switch to a K3.

As far as birdies, most radios have birdies.  Modern radios are so sensitive and selective that they can pick up the digital modem two houses away on 6” of wire. We live in a digital world and there are noise sources everywhere!  Even in the K3.  

I had birdies in my Icom 781, my WJ 8711’s and my K3. They were/are all below the atmospheric noise level. Never a problem!   My PL noise was far worse.  

Good topic, Bill!

John Perlick
Aria Corporation
www.ariacorp.com

> On Jun 3, 2018, at 1:17 PM, "elecraft-request at mailman.qth.net" <elecraft-request at mailman.qth.net> wrote:
> 
> rom: elecraft-bounces at mailman.qth.net
> [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Bill
> Sent: 3. juni 2018 15:17
> To: elecraft at mailman.qth.net
> Subject: [Elecraft] Compare: K3 to Collins S-line receiver
> 
> Discounting the digital capabilities such as memories, DSP, etc. and 
> only considering actual signal reception: I have had S-lines in the past 
> (dark dim past), so certainly am familier with them. However, as a point 
> of curiosity, how does the S-line compare to the K3 (only interested in 
> SSB). Basically, I am interested in how a top of the line analog 
> receiver does compares to a K3(S)? The question comes from a QSO 
> regarding the microprocessor noise of modern rigs covering and/or 
> distorting received signals. Offline response might be good for this, as 
> I am sure not many would be interested in the subject.
> 
> Thanks, Bill W2BLC K-Line
> 
> __________________