Transmit 8 Volt line... Which goes to +8 volts DC when put into transmit mode.
On the schematic, it's depicted at T8.
73
Jim W7RY
From: rick darwicki
Sent: Friday, December 09, 2011 7:31 PM
To: Jim W7RY
Subject: Re: [Amps] ICOM PRO III QSK
What do you mean by the T8 line?
Rick, N6PE
=============================================================================
From: Jim W7RY <jimw7ry@gmail.com>
To: "Joe Subich, W4TV" <lists@subich.com>
Cc: rick darwicki <n6pe@yahoo.com>; amps@contesting.com
Sent: Friday, December 9, 2011 2:53 PM
Subject: Re: [Amps] ICOM PRO III QSK
I've not used the H-Send line. I like to use the T8 line. It would be
interesting to tap it and make the same tests.
73
Jim W7RY
--------------------------------------------------
From: "Joe Subich, W4TV" <lists@subich.com>
Sent: Friday, December 09, 2011 9:40 AM
To: "Jim W7RY" <jimw7ry@gmail.com>
Cc: "rick darwicki" <n6pe@yahoo.com>; <amps@contesting.com>
Subject: Re: [Amps] ICOM PRO III QSK
>
> > Here is the site I was thinking of:
> >
> > http://w0qe.com/amplifier_timing.html
>
> Yes, that's one of the sites I was looking for. You will notice that
> in all of the Icom radios shown, *including* the IC-746Pro and 756Pro,
> the HSEND line (cyan in the scope pictures) went high between 4.5 and 9 ms
> *before* RF ended in full QSK.
>
> Using the HSEND/SEND output from the ACC jack with a vacuum relay will
> result in hot switching the relays on the transition from transmit to
> receive and will result in relay destruction unless the amplifier has
> some (10 ms minimum) delay on break.
>
> 73,
>
> ... Joe, W4TV
>
>
> On 12/9/2011 12:23 PM, Jim W7RY wrote:
>> Here is the site I was thinking of:
>>
>> http://w0qe.com/amplifier_timing.html
>>
>>
>> 73
>> Jim W7RY
>>
>>
>> --------------------------------------------------
>> From: "Joe Subich, W4TV" <lists@subich.com>
>> Sent: Friday, December 09, 2011 8:01 AM
>> To: "Jim W7RY" <jimw7ry@gmail.com>
>> Cc: "rick darwicki" <n6pe@yahoo.com>; <amps@contesting.com>
>> Subject: Re: [Amps] ICOM PRO III QSK
>>
>>>
>>> > I have seen that too but it was strictly limited to the IC-7000.
>>>
>>> The study I saw (not the AD5X article) was not limited to the IC-7000.
>>> The "premature release" applied to all of the "small" radios 706/7000
>>> as well as several of the full size radios - including 7700, 746Pro,
>>> and I believe the ProIII - when using the ACC jack instead of the
>>> Send relay.
>>>
>>> 73,
>>>
>>> ... Joe, W4TV
>>>
>>>
>>> On 12/9/2011 10:36 AM, Jim W7RY wrote:
>>>> I have seen that too but it was strictly limited to the IC-7000.
>>>>
>>>> 73
>>>> Jim W7RY
>>>>
>>>>
>>>> --------------------------------------------------
>>>> From: "Joe Subich, W4TV" <lists@subich.com>
>>>> Sent: Friday, December 09, 2011 7:12 AM
>>>> To: "rick darwicki" <n6pe@yahoo.com>; <amps@contesting.com>
>>>> Subject: Re: [Amps] ICOM PRO III QSK
>>>>
>>>>>
>>>>> I don't have the link at hand or time to go looking for it right now
>>>>> but I've seen a rather extensive examination of T/R switching that
>>>>> shows the Icom rigs generally hot switch on returning to receive in
>>>>> QSK when using the "SEND" or "HSEND" line from the ACC jack. That
>>>>> is, the SEND/HSEND signal releases roughly 5 ms *before* the Icom
>>>>> transceiver stops producing RF.
>>>>>
>>>>> Drive to the "send" relay includes roughly 5 ms delay necessary to
>>>>> prevent early release of the amplifier relay. AD5X has a circuit for
>>>>> the ACC output at; www.ad5x.com/images/Articles/QSK%20Delay.pdf.
>>>>>
>>>>> An amplifier with vacuum relays will need at least 10 ms delay - 5 ms
>>>>> to overcome the "early" release on the SEND line plus 5 - 7 ms for
>>>>> normal operation.
>>>>>
>>>>> 73,
>>>>>
>>>>> ... Joe, W4TV
>>>>>
>>>>>> From: "rick darwicki"<n6pe@yahoo.com>
>>>>>> Sent: Wednesday, December 07, 2011 11:12 AM
>>>>>> To:<amps@contesting.com>
>>>>>> Subject: [Amps] ICOM PRO III QSK
>>>>>>
>>>>>>> Hi all,
>>>>>>>
>>>>>>> Does anyone know it the timing on the ICOM PRO III linear amplifier
>>>>>>> SEND
>>>>>>> line is such that the AMP will not be hot switched on FULL BREAK IN?
>>>>>>>
>>>>>>> I have an old Alpha 76 and can install vacuum relays for QSK if the
>>>>>>> timing
>>>>>>> is OK out of the PRO III.
>>>>>>>
>>>>>>> Thanks,
>>>>>>>
>>>>>>>
>>>>>>> Rick, N6PE
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> Amps mailing list
>>>>> Amps@contesting.com
>>>>> http://lists.contesting.com/mailman/listinfo/amps
>>>>
>>>>
>>
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