Does anyone know the RF voltage/current rating (at sea level) of a typical type
N connector.
I have heard various opinions on this connector ranging from "It should never
be used in high
power applications at HF" to "You can 10KW thru them". Recently, I have seen two
catastrophic failures involving type N connectors at HF frequencies. In both
cases, the male
center pin and the female socket were welded together and the connection was
filled with
black carbon like deposits. In both cases, legal power was involved (Ameritron
AL-82 and
Alpha 78).
With a 1:1 VSWR into 50 ohms, 1500 Watts corresponds to 5.5 amps rms and 270
volts rms
respectively. Given the airgap size in the series N connector, I would expect
the breakdown
voltage to much higher than this (one old Mil spec I found for a type N adapter
suggested
1500 volts rms). My gut feeling is that these failures are due either to
improper installation,
or poor quality connectors (plastic dielectric vs teflon). Are there any
published specifications
for the series N (UG-21) connector and the UHF connector (PL-259) that compares
there
voltage and current handling capability in some meaningful way (I couldn't find
much on the
DSCC web site)?
One of the connectors that needs replacing is a 7/8" hardline to N connector
that is located
at the top of a 70' tower. I don't want to have to replace this thing again!
Thanks,
Mike, W4EF.....................
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