[Icom] IC-756pro2

[George, W5YR]

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>





----- Original Message -----
From: "Paul Playford" <w8aef@worldnet.att.net>
To: <icom@mailman.qth.net>
Sent: Tuesday, August 05, 2003 12:17 PM
Subject: Re: [Icom] IC-756pro2


>
> ----- Original Message -----
> From: "George, W5YR" <w5yr@att.net>
> To: <icom@mailman.qth.net>
> Sent: Tuesday, August 05, 2003 3:39 AM
> Subject: Re: [Icom] IC-756pro2
>
>
> SNIP, SNIP
>
> >
> > I find that break-in on the 746PRO to be better than on the PRO and
PRO2,
> > but none are as good as my IC-765 when it comes to QSK. Icom got that
one
> > right!  <:}
> >
>
> I beg to differ with you on this one.  When I compared the non QSK to QSK
> output waveform on my 765 I found the QSK element trailing edges were
> chopped off by 8 ms.  I added a capacitor across the 765's FULL BK-IN
switch
> contacts to enable the VOX long enough to complete each element.  As I
> recall the Frankfort radio club published the same fix in their news
letter.
>
> Keep up the good work.
>
> de Paul, W8AEF