Tom,
It'll do more than cause an arc if I inject 100 watts into my amplifier
:) It'll most likely destroy it.
Given that we are now way down the road of radio equipment development
what sort or person calls himself a radio engineer that can't design a
transmitter without a keying pulse, at least one ICOM so called radio
engineer who I hopes reads this newsgroup.
I presume it was found a quicker fix to use ALC to control the output
rather than any other means and as we known ALC is a negative feedback
system that >initially< responds after the event.
Looks like 100 watts and an attenuator pad is needed :(
Paul
In message <200101032309.f03N9Vc15300@paris.akorn.net>, Tom Rauch
<w8ji@contesting.com> writes
>
>Hi Paul,
>
>> Has anyone come up with a solution to the problem of the large pulse
>> produced from an ICOM 706 when initially keyed and even with the power
>> output turned down?
>
>First, run only 12 volts if you can. The more voltage the bigger the
>pulse.
>
>Second, apply a fixed external negative bias on the ALC input line
>on the radio. Set it to limit power to a safe value with ICOM power
>all the way up.
>
>Third, use a pad if you can or plan the amp input for a full 100
>watts.
>
>That spike is nasty on several ICOM radios, particularly the
>775DSP. It can be the start of a bandswitch or tuning cap arc,
>especially if the amp isn't loaded heavy enough.
>
>
>73, Tom W8JI
>w8ji@contesting.com
>
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>
>
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