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Old May 23rd 05, 06:24 PM
Richard Clark
 
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On 23 May 2005 04:49:08 -0700, "
wrote:
While measuring the SWR, the needle fluctuates, as the voice is
modulated. Is the "value of SWR" the highest it hits? What's the
convention?


Hi Ramakrishnan,

This is why you need to do it with CW, and why you need an external
meter/tuner. Building a meter is actually quite simple (although
recent correspondence here would contest that statement).

SWR should not vary. It is dependant upon the mismatch of the
transmitter to the load alone. When you get variations of SWR
readings depending upon signal strength, the problem is often an issue
of the meter, and then, secondarily, the transmitter's source
resistance. This is why you should tune at the level you are going to
transmit at. You can first get into the neighborhood with lower
levels while tuning (although you lack a tuner) and then boost to the
anticipated power for the last adjustment.

73's
Richard Clark, KB7QHC