>
>Rich wrote:
>
>> ? I agree that current transients brought about by hotswitching
>> stimulate parasites. . However, bending contact supports will not
>> prevent hotswitching if RF comes down the pipe before the relay contacts
>> have stopped bouncing. The fix for hotswitching is either to buy a
>> TS820S, or to install high speed switching (approx. $60).
>
>Not true.
>
>If you simply close the antenna connection contact before the input
>connection contact, all internal arcing problems from hot-switching
>disappear.
>
? Even so, driving RF will be across the input contacts before they
close. This will result in arcing the input contacts during closure.
>That simple change makes sure the amplifier is connected to a
>load before drive is applied.
>
>It does not cure the leading edge click that is generated when the
>relay closes while RF is present, but at least it stops bandswitch
>and tuning cap failures, and other arcs caused by hot switching.
>
? If input contact arcing takes place, transients are fed to the input
of the amplifier tube. If these transients stimulate intermittent vhf
oscillations, it doesn't matter if the output relay contacts are closed
or not since vhf energy can not pass through the low-pass hf tank.
>
- cheers, Tom
Rich...
R. L. Measures, 805-386-3734, AG6K, www.vcnet.com/measures
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