[AMPS] N Connectors

[Michael Tope]

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.....................


--
FAQ on WWW:               http://www.contesting.com/ampsfaq.html
Submissions:              amps@contesting.com
Administrative requests:  amps-REQUEST@contesting.com
Problems:                 owner-amps@contesting.com
Search:                   http://www.contesting.com/km9p/search.htm