[Icom] IC-756pro2

[Paul Playford]

Looks like I didn't do all of my homework on this.  I use an external keyer
with my rigs so that may be the difference.  My 765's sn is 2318 and the way
I made my observations was trigger a dual trace scope with the keyer and
look at the RF envelope.  The leading edge of each element in the RF
envelope was delayed 8ms from the keyer but the trailing edge was coincident
with the trailing edge.  And the PROII is the same but I have not found a
fix for the PROII as that's digital.

Vive la difference!

de Paul, W8AEF

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ZF2TA  FO8DX  FO0PLA  8Q7AA  XZ0A
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----- Original Message ----- 
From: "George, W5YR" <w5yr@att.net>
To: <icom@mailman.qth.net>
Sent: Wednesday, August 06, 2003 4:56 AM
Subject: Re: [Icom] IC-756pro2


> Paul, I just got through examining the r-f output envelope of the 765 with
> the scope while I keyed it with strings of dits, dahs, alternate dits and
> dahs, etc. using the internal keyer.
>
> I cannot tell from the scope that the old gal is putting out anything but
> perfectly timed and spaced CW. The dot/space ratio appears to be 1:1 at
all
> speeds up to the max of the keyer. The dot/dash ratio is 1:3 at all
speeds.
> Dashes are three times as long as spaces. Everything by the book . . .
>
> I cannot find any evidence of element truncation anywhere, either in full
> break-in (QSK) or VOX-mode keying (semi-QSK).
>
> The output timing and spacing are far superior to the PRO2 or the 746PRO
> which both suffer from dot shortening as speed in increased.
>
> But, the transparency of the QSK is much better with the 746PRO than with
> the PRO2 and both beat out the 765, contrary to what I remembered. In
fact,
> the 746PRO QSK is actually annoying since you hear the receiver while
keying
> almost as if you weren't and sometimes the background signal/noise is
> distracting. With the 765, when keying there is no sense of hearing "the
> other end" between code elements.
>
> So, I back up on the 765 having better QSK than the PROs - it doesn't.
But,
> the code timing and spacing is well nigh perfect on the 765 and not so for
> the PROs.
>
> Guess 50% isn't all bad!
>
> Serial number for the 765 is #2437. I have no idea when or if any factory
> mods were made to the keying logic, but my rig definitely does not show
the
> truncation that you described.
>
> I have made no modifications to the  keying circuitry.
>
> 73/72, George
> Amateur Radio W5YR -  the Yellow Rose of Texas
> Fairview, TX 30 mi NE of Dallas in Collin county EM13QE
> "In the 57th year and it just keeps getting better!"
> <mailto:w5yr@att.net>
>