on 2/25/00 9:27 AM, Michael Tope at W4EF@pacbell.net wrote:
> 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).
Well, after a lot of blather from people saying, "Well I've done this or
I've seen this." you still don't have an answer for your question of
ratings.
I sell connectors as part of my living and have real numbers available for
you, not ham type speculation and experimentation!
For standard 50 Ohm N-connectors:
VSWR: ~1.04:1 (up to 1.2:1 at 11 GHz)
IM Products: -90 dBm (-133 dBc @ 20 Watts)
Insertion loss (straight connector): < 0.15 dB max at 10 GHz
RF Leakage: -90 dB min from 2 to 3 GHz
Insulation Resistance: 5000 MOhms min
Contact resistance: 1 mOhm (center), 0.2 mOhm (outer)
Sea level Working voltage in VRMS (for RG213): 1400 Volts
(for RG58): 850 Volts
Dielectric Withstanding Voltage: 2500 V (RG213), 1500 V (RG58)
RF Testing Voltage: 1500 VRMS (5 MHz SineWave)
The maximum power that is specified through the connectors is 8 KW (I=13 A)
up to 10 MHz. At 20 MHz, the maximum power is rated at 4.75 KW and at 30
MHz it is just over 4 KW. At 100 MHz, the rated power is just over 2 KW, at
400 MHz the rated power is 1 KW, and at 500 MHz, the rated power is 900
Watts. The connector derates to about 180 Watts at 10 GHz. Beyond 10 GHz
the connector starts to go into other modes than the TEM mode.
The connector is also rated at 100% power up to 25 degrees C. At 50 C, it
drops to 80%. It falls linearly to 0% at 155 C.
There, that should help!
The others are correct when they talk about the need to have good center pin
contacts with the N connector. The center pin is very small and as such
needs to be mated well and it needs to be neither too short nor too long.
Remember that the business part of an N and a BNC are the same!
I hope this helps everyone on the list.
73,
Jon
KE9NA
-------------------------------------
Jon Ogden
KE9NA
Member: ARRL, AMSAT, DXCC, NRA
http://www.qsl.net/ke9na
"A life lived in fear is a life half lived."
--
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
|