With INSULATED wire a simple pickup loop - a metal coathanger always worked
well with the panel lamp connected in place of the handle - per the 1938 ARRL
Antenna Book. It still needs to be insulated, though.
I never tried to connect directly to open wire line but a two feet of
insulated wire with the bulb in the middle - like this __________|
|___________,
with the two uprights representing the bulb holder, has plenty of capacity to
couple to a feedline, even on 160. It worked quite well for tuning up an ARC5
with a pair of 1625's back in the 1940's, it should work just as well today.
For an Argo, I 'spect I would go to some of the 100 ma subminiature bulbs,
though.
But to check for balanced currents, you need to "read" both sides of the
transmission line at the same time.
73 Pete Allen AC5E
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