[Elecraft] Fwd: New Sherwood report

[Paul Christensen]

4 ms.  Given that the FTdx5K rise/fall is roughly double the time of the 
K3 -- and that the K3 at 2 ms consumes significantly less bandwidth than the 
FTdx5K at 4 ms, the CW transmit quality of the K3 is far superior.  I would 
like to hear QSK on the Yaesu, compare it with the K3's QRQ mode, and note 
any audible artifacts in the headphones -- especially for signs of clicks 
and DC thumps.

Referring to the December, 2010 QST Product Review on p.45, take a look at 
the leading edge of the second pulse (lower trace) in Figure 1.  The sharp 
rise and sharp edge at the top of the waveform is what is consuming the 
bandwidth.  Based on that waveform, it was absolutely generating clicks at 
some distance from the Fc.  That pattern is characteristic of a deficient 
ALC system.

A deficiency in the ALC system then takes us into SSB Tx IMD.  The published 
FTdx5K Tx IMD numbers look great with the ARRL's steady tone method but 
arguably, that's probably more relevant to data modes.  The question is 
"what is the FTdx5K's ALC doing to undermine the rig's otherwise excellent 
SSB Tx IMD numbers, especially in Class A?"  Really, the published Tx IMD 
figures are meaningless unless dynamic testing is conducted to simulate 
rapid changes in power associated with voice modes.

Paul, W9AC

----- Original Message ----- 
From: "Jan Erik Holm" <sm2ekm at telia.com>
To: <elecraft at mailman.qth.net>
Sent: Friday, December 03, 2010 8:27 AM
Subject: Re: [Elecraft] Fwd: New Sherwood report


> Yes but to what rise/fall time was the radio set? AFAIK in
> the FT5000 it can be changed.
>
> /Jim SM2EKM