> Add 0.25-0.50 dB for any connectors/adaptors if used above 50Mhz
This is another one of those old wives' tales that has no basis in fact
-- they are the big lie that is believed simply because it is so often
repeated. The loss in any decent RF connector is a tiny fraction of a
dB. W8JI has a rather simple way of helping us think through the
silliness of your statement. 0.5dB is a power ratio of 0.8913. If
you're running 1.5kW through that connector, a loss of 0.5dB is 163
watts. Think about the heat from a 163 watt light bulb inside that
connector. Or with a high duty cycle typical of contesting, 50 watts
average power.
Such large losses only occur with junk connectors, like those with the
tiny springs for a center conductor. Now, I DID experience that kind of
heating with that sort of junk connector, at at that power level -- it
was VERY HOT after less than an hour of contesting. When I replaced it
with an Amphenol, it ran cool as a cucumber.
This spring, VE1RAC sent me documentation of some very good experimental
work he had done showing that the loss in decent connectors at VHF is
FAR lower than that -- a few HUNDREDTHS of a dB, as I recall.
73, Jim Brown K9YC
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