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

[Larry Benko]

Paul,

I borrowed my friends 756PRO2 and built a 2 transistor interface to go 
into the ACC plug and key my amp (Acom 1000) which has keying 
requirements of 12V DC at 10mA.  I used this interface with my 756PRO 
and 746PRO with no problems.  Then I tried the 756PRO2 and again no 
problems.  I made about 10 CW contacts using full QSK and my amp has 
extensive protection circuitry including detection of hot switching and 
it did not complain at all.  Therefore my results do not agree with 
yours.  I thought I would get back to you and let you know what the 
results were.

73,
Larry, W0QE

paul at w8aef.com wrote:

> Our dit element shortening observations do agree.  And I use a CMOS 
> Super Keyer III, which I really like.
>
> It will be awhile, at least after Field Day, but I will keep you posted.
>
> de Paul, W8AEF
>
> ----- Original Message ----- From: "Larry Benko" <w0qe at bnk.com>
> To: "ICOM Reflector" <icom at mailman.qth.net>
> Sent: Saturday, June 18, 2005 2:02 AM
> Subject: Re: [ICOM] AMP INTERFACE TO 756 PRO II (CONTINUED)
>
>
>> Paul,
>>
>> I no longer have the 756PRO2 here since I borrowed it from a neighbor 
>> ham when I made the measurements.  I do have a 756PRO, 746PRO, 765 
>> and 706mkIIG here.  The last time I measured them the first dot/dash 
>> in semi-QSK and every dot/dash in full-QSK mode was shortened overall 
>> about 8ms and slightly more on the 706.  The shortening was a 
>> constant time amount and not dependent on CW speed and I was using an 
>> external keyer. The Logikey K3 keyer I use has the option K=05 set to 
>> extend all CW dots/dashes by 5ms.  This was an attempt at a 
>> compromise since I operate full-QSK only some of the time.  Please 
>> let me know if you make any more measurements since my measurements 
>> did not match yours.  I made the original measurements as part of 
>> some other measurements and I was transmitting 100w into a dummy load 
>> and sending a continuous string of dot and dashes at 30wpm (dot = 
>> 40ms.).  I will try to borrow my friend's 756PRO2 again and remake 
>> the measurements.
>>
>> 73,
>> Larry, W0QE
>>
>> paul at w8aef.com wrote:
>>
>>>
>>>
>>> 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
>>>>
>>>
>>> ----
>>> Your Moderator: Dick Flanagan K7VC, icom-owner at mailman.qth.net
>>> Icom Users Net: Sundays, 1700Z, 14.316 MHz
>>> Icom FAQ: http://www.qsl.net/icom/
>>>
>>
>> ----
>> Your Moderator: Dick Flanagan K7VC, icom-owner at mailman.qth.net
>> Icom Users Net: Sundays, 1700Z, 14.316 MHz
>> Icom FAQ: http://www.qsl.net/icom/
>>
>>
>
> ----
> Your Moderator: Dick Flanagan K7VC, icom-owner at mailman.qth.net
> Icom Users Net: Sundays, 1700Z, 14.316 MHz
> Icom FAQ: http://www.qsl.net/icom/
>