[Elecraft] P3TXMON Question?

[Edward R Cole]

When I need to know accurate power readings my best instrument is 
either scope and good 50-ohm termination, or using my HP432A mw power 
meter.  Its about 1/2 dB accurate.  But +10mw is the highest scale so 
you need several high power coaxial attenuators to measure 
power.  40dB will permit measuring +50-dBm (= 100w).

I have a lot of Bird elements and rely on the Bird for day-to-day 
measurements, but do realize the Bird's limitation. I measure from 
-20 dBm to +62 dBm in my ham shack.  The latter is 1500w. I use 
2500H, 2500B, 1000A or 1000D elements.  5w is my smallest element.

But for really precise SWR I use directional couplers and calibrated 
open, short and 50-ohm terms.  They are never subjected to over +10 
dBm.  Return loss is what is actually measured and one can use a 
conversion chart to determine SWR.  If I had the money then a VNA is 
the optimum instrument.  But the average ham does not need that.

73, Ed - KL7UW
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