On 8/2/14, 1:10 PM, Steve Hunt wrote:
Rick,
I already corrected this misunderstanding once: for a 2:1 SWR the
maximum voltage will be 1.414 times the matched voltage, not double! The
minimum voltage will be 0.707 times the matched voltage.
If V is the matched line voltage, Vmax=1.414xV and Vmin=V/1.414 giving
Vmax/Vmin=2:1
Steve G3TXQ
Power dissipation, though, will be 2x (which I think was what we were
talking about..
My off the cuff question was more along the lines of "are the current
maxima at the same place as the voltage maxima": that is, is max
dielectric dissipation going to occur at the same place as max copper
loss dissipation, or are they going to be, say, 90 degrees apart.
In a matched line, voltage and current maxima occur at the same place
because current and voltage are in phase.
But in a mismatched line that's not necessarily the case.
(Of course, Rick's "do you feel lucky" applies here.. I'd design for the
worst case, but there might be some time where you know where the "hot
spots" are going to be.)
On 02/08/2014 19:00, Richard (Rick) Karlquist wrote:
For 2:1 VSWR, 2X is the worst case, which you would want to use for
design. In practice, it could vary from half to twice the matched
value for a short section of line.
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