> 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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