A valid point Terry, although isolation may not be as good as the
transistor, but then again, it may not need to be. In my case, I need the
added isolation, because I create an open-collector amp key line for my
choice of three amps and four rigs! In essence, I have a high isolation
keyed buss line.
Taking your suggestion, it appears that only one external diode is required.
D16 performs the necessary isolation after summing on the TX EN line.
It would be interesting to see if this works in conjunction with an RCA "Y"
adapter, running two ends between TX OUT and TX EN, then running the third
wire on out to the external diode and then the amp.
In any event, let us know how this works using the external steering diode.
73,
-Paul, W9AC
-----Original Message-----
From: w6ru <w6ru@lightspeed.net>
To: Paul Christensen <paulc@mediaone.net>; tentec@contesting.com
<tentec@contesting.com>
To: <tentec@contesting.com>
Date: Sunday, September 20, 1998 8:47 PM
Subject: Re: [TenTec] Omni QSK with Alpha's 87A QSK
>Paul,
>Your modification requires a person to go inside the radio and make a
change to
>a SMC circuit board in regards to Q16.
>Q11's collector is already present at the "TX OUT" jack. This is what I am
>suggesting Jim and others who do not want to get inside their radios, use
to key
>BOTH the "TX EN" jack and the "RELAY" jack on the 87A...through steering
diodes
>external to the radio. Take the keying line from the "TX EN" jack through a
>diode...take the 87A "relay" jack line through a diode...sum them together
into
>the "TX OUT" jack.
>
>Terry - W6RU
>
>Paul Christensen wrote:
>
>> Terry:
>>
>> The steering diodes are not necessary. All the parts needed are already
>> there. The input to R29 is bridged across the TX OUT line. Then, the
>> collector of Q16 is sent directly to the RELAY RCA jack.
>>
>> End of Modification.
>>
>> -Paul, W9AC
>>
>> -----Original Message-----
>> From: w6ru <w6ru@lightspeed.net>
>> To: Jim Reid <jreid@aloha.net>; tentec@contesting.com
>> <tentec@contesting.com>
To: <tentec@contesting.com>
>> Date: Sunday, September 20, 1998 8:34 PM
>> Subject: Re: [TenTec] Omni QSK with Alpha's 87A QSK
>>
>> >
>> >My error !
>> >This time I see the keying of this circuit...not sure why it didn't show
>> the
>> >first time.
>> >THIS MAKES IT SIMPLE...
>> >Just let that "TX OUT" jack key BOTH the "TX EN" jack on the Omni 6 AND
key
>> the
>> >"RELAY" jack on the 87A. I would use two steering diodes, one in each
>> circuit
>> >to isolate the circuits from each other in the receive mode.
>> >Hope this helps.
>> >Terry - W6RU
>> >
>> >
>> >--
>> >FAQ on WWW: http://www.contesting.com/tentecfaq.htm
>> >Submissions: tentec@contesting.com
>> >Administrative requests: tentec-REQUEST@contesting.com
>> >Problems: owner-tentec@contesting.com
>> >Search: http://www.contesting.com/km9p/search.htm
>> >
>> >
>>
>
>
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