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[CQ-Contest] Clicks

Subject: [CQ-Contest] Clicks
From: n2mg@contesting.com (Mike Gilmer - N2MG)
Date: Wed Mar 7 10:54:38 2001
On Tue, 06 March 2001, Bill Fisher W4AN wrote:

 > K1AR asked me to post this so you guys would quit
 > picking on him

I thought JD liked that!

I wish the "clicks" survey was a little more
complete...like how many people with FT1000's did NOT
have the problem?

I've been using a TS-940 and an ARD230 amp (yup, 11+
year old technology) for a few years.  I noticed that
when ever I started transmitting on CW, I would get a
short spike on the 940's SWR meter.  Obviously, that
meant that the amplifier was being sent RF from the
940 before the amp had actually finished being
switched into TX.  I can only assume that this could
cause key clicks as it creates a harsh leading edge to
the waveform as the amp relay closes with live RF
already on it.

Anyone who knows this amp, knows it has a key
input so that the amp can be keyed at the same time as
the radio; using this visibly eliminated the "spike"
on the 940's SWR meter.

The phenomenom of a TS940 sending RF out the back
before its T/R relay that drives the amp actually
switches is rather legend by now.  I had already
opened the radio years ago and installed a "speed up"
capacitor in the relay drive circuit, and had recently
replaced the entire T/R relay with a solid state
circuit (SWR still "spiked") but using the key input
on the ARD was what finally "cured" it.

However, with the high-SWR power cutback that occurs in these radios, the 
RF output was probably so low
that no clicks of any magnitude were actually
generated - at least not caused by the hot-switching
of the amp.  True?  Probably time to get out some test equipment.

73 Mike N2MG

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