[ICOM] QST Review of IC-7600

[Adam Farson]

Hi Bob,

To repeat my recent post on this subject:

It is possible that the Drive Gain was incorrectly set during the ARRL test
suite, resulting in ALC overshoot and distortion of the leading edge of the
keying waveform.

Quoting Peter Hart's RSGB review (RadCom, June 2009): "The CW fall times are
as set and appear fairly optimal. The rise time, however, is strongly
dependent on ALC setting and at half ALC rise times are about three times as
long as the set value. This can cause some character shortening at high
speeds."

Regrettably, I did not check the CW waveform when I ran my test suite. (I
intend including this test in my beta-test plan for the future.) The CW
sidebands at 50 wpm looked pretty decent on the spectrum analyser.

http://www.ab4oj.com/icom/ic7600/7600notes.pdf page 25

The upshot of this is that the operator can adjust the ALC for optimum CW
rise-time via the [DRIVE] control. So I would not dismiss the 7600 as a "CW
op's radio" out of hand. Peter Hart certainly did not.

Cheers for now, 73,
Adam VA7OJ/AB4OJ
 

-----Original Message-----
From: icom-bounces at mailman.qth.net [mailto:icom-bounces at mailman.qth.net] On
Behalf Of Bob Beatty
Sent: 21-Oct-09 13:37
To: icom at mailman.qth.net
Subject: [ICOM] QST Review of IC-7600

In the review I saw no comment regarding the very slow rise time of the
second dit in Figure 3. If this is representative of the rig's keying, it
must sound terribly mushy.  The reviewer paid a lot of attention to other
features but must not be a CW operator as this appears to be a glaring
problem with the rig.

73,

Bob W4VQ
I do CW