This meter uses some 50 Ohm thick-film resistors to form a 50-Ohm dummy load and a conventional detector to drive the meter.
I made up the instrument according to the clear instructions - with the exception that I substituted a 1N5711 for the 1N4148 specified in the words and music (as I intend to use the Sandford's detector in some comparisons with a digital meter I've been playing with).
You can see the thick-film power resistors and the (blue) 5711 diode here...
My diode substitution required me to make a little modification to the metering circuit to allow the system to be calibrated correctly - but everything was soon back on track. The instructions give a nice little wheeze for calibrating with a d.c. source - useful for those with limited test equipment.
I needed some application to test the new meter on - so thoughts turned to the recently-acquired Patriot...
I measured power output generated on key-down in CW mode across both 40 and 20m bands and show the results in the graphs below...
This is a neat little meter and a nice addition to the test bench - certainly easier than getting out a dummy load and hooking up to the scope (or choosing a dummy load with an integral detector and connecting to a multimeter) and doing the math.
Perhaps not so much fun, though!
...-.- de m0xpd
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