[ICOM] IC-751A Key Clicks (Again)

[Don]

Regarding ICOM-751A keyclicks,
I set-up my 751A as you asked and with RF drive at minimum the
ALC reads just above mid scale and slowly decreases to just
below mid scale at RF maximum.  I don't have key clicks.
73
Don
KA1A

-----Original Message-----
From: icom-bounces at mailman.qth.net [mailto:icom-bounces at mailman.qth.net] On
Behalf Of Ed Swynar
Sent: Monday, December 19, 2005 5:10 PM
To: ICOM Reflector
Subject: [ICOM] IC-751A Key Clicks (Again)

Good Evening All,

I wonder if anyone reading this --- and who owns an Icom 751A --- might
indulge me, please, with a small favour...?

Specifically, with the rig set-up to transmit in semi-break-in CW, turn the
RF drive fully counterclockwise...now, with the meter selected to the ALC
position,  hold the key down to send out a carrier. What does your meter
show for ALC deflection at this point?

Next, gradually turn the RF drive control to maximum (clockwise adjustment)
while holding the key down, and observe the ALC deflection in the meter...

If your rig is like mine, you will have seen a good half-scale deflection,
or more, in ALC with low power output, & then even more ALC at maximum
output.

This confuses me: I always believed that ALC was not activated until such
time as an overdrive condition was approached...in the low power setting of
the RF drive control, why would there have even been an ALC indication? On
my Yaesu FT-980, there is NO ALC meter movement whatsoever until the
100-watts of specified output is approached, or exceeded --- the 751A starts
out high in ALC from the get-go! 

In fact, the Yaesu manual cautions the operator that generation of key
clicks may well result at the point of ALC meter deflection...

What got me thinking of this was reference in an 80's issue of QST magazine
--- a fellow therein stated that improperly "...thresholded" ALC can, and
does, contribute to the generation of key clicks in modern transceivers...

Many thanks for any & all assistance & observations in this regard with your
own 751A...

~73~ Eddy VE3CUI - VE3XZ
----
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