[ICOM] AMP INTERFACE TO 756 PRO II (CONTINUED)

[paul at w8aef.com]

I used my Tektronix 465 dual trace oscilloscope to make my observations. 
If/when I put the radio back on the bench I will look again but when I made 
the original observation I concluded that it was in the digital portion of 
the radio controls, and I don't want to go there.

And the fault was observed while operating into any one of several monoband 
antennas, 20 wpm cw qsk, Alpha 76 at full power out.  The trouble shooting 
was done into one of my several dummy loads.

Further, my 761 and 765 did not have this characteristic.

As an aside, how much is the first dit truncated during cw (non qsk) on your 
PRO2?

de Paul, W8AEF


----- Original Message ----- 
From: "Larry Benko" <w0qe at bnk.com>
To: "ICOM Reflector" <icom at mailman.qth.net>
Sent: Friday, June 17, 2005 11:58 PM
Subject: Re: [ICOM] AMP INTERFACE TO 756 PRO II (CONTINUED)


> Paul,
>
> I 100% disagree with you.  I have measured several Icom rigs (706mkIIG, 
> 746, 746PRO, 756, 756PRO, 756PRO2, 765) and on all radios both the "SEND" 
> line and the relay precede any RF by 9 to 11 ms. on key down and both 
> remain active for approximately the same time after the rf quits on key 
> up.  I have made some postings to this reflector with the absolute data in 
> the past.  Search on my call to find it.  If you have evidence based on 
> scope measurements (do not run scope in alt. channel trigger mode) please 
> post it.   My amp is keyed directly from the send line through a 
> transistor buffer allowing more than 1 radio to key the amp. and have 
> never had any problems.  If you have problems I would suggest you try the 
> experiment when operating into a dummy load.  If your problems go away 
> then the problem is RF getting into the circuit.  While RF might get into 
> the send line a relay is much more RF resistant.
>
> 73,
> Larry, W0QE
>