[Amps] Ten-Tec Centurion

[R.Measures]

On Nov 10, 2004, at 7:40 PM, k7fm wrote:

> Rich said:
>
> "RF must be in the amplifier to trigger the RF sensing which causes the
> relays to close.  How could RF not be on the NO relay contacts as they 
> are
> closing and yet be on the RF sensing circuit that is energizing the 
> relay
> coils?"
>
> Assuming the spike is at the leading edge of the transmitted signal, 
> then an
> rf sensing circuit could delay the turn on of the rf amplifier until 
> after
> the passing of the spike.

Colin -- The problem is that incoming RF does not go on a mini-vacation 
immediately after the spike, it merely backs down to the ALC level that 
is set.  Thus, there is RF on the closing NO contacts while they are 
bouncing.  This results in hot-switching and current-transients.

>  If that was the case, then the arcing from the
> leading edge spike might not occur.  According to the facts given us 
> by Tom,
> he did not experience any arcs while the amplifier was rf sensing.  
> That
> would be one explanation.  It might be the most logical one, too.  It 
> is a
> simpler, less convoluted approach than parasitics.

Measuring the actual resistance of the parasitic suppressor resistors 
and eye-balling their appearance could eliminate parasitics as a 
possible scenario in under 2-minutes - if the soldering-iron is hot.  
Not measuring R-supp will not.
>
> K2VCO provided a method of reducing or eliminating the spike and that 
> would
> be worth trying out.

An oscilloscope tells us that backing down the microphone gain control 
eliminates the spike every time.
>
> Colin  K7FM
>
>
>
>
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Richard L. Measures, AG6K, 805.386.3734.  www.somis.org