It's difficult to argue with Frank's experience and expertise. That said, fools
rush in...
I own some network analyzers, 1) an N2PK which I built with type N connectors,
2) a DG8SAQ VNWA-3, supplied with SMA connectors and 3) a RigExpert AA-55 Zoom
with a SO239. Professionally, I've used analyzers with type N, 3.5mm (beadless
SMA) and K connectors. With the exception of the AA-55, which only goes to 55
MHz, all of these can be calibrated with "precision" calibration kits that can
cost thousands of dollars. So far, Frank is right, not a BNC in the bunch.
But that has changed with the introduction of the DG5MK's FA-VA5, one-port
vector analyzer. I am on the reserve list to buy one of these. The thing to
note is that it is supplied with a BNC connector. There has been a lot of
anguish, heartburn, etc about this on the VNWA Yahoo group but the consensus is
that it will be fine and BNC calibration kit has been developed and tested
without issue. https://www.youtube.com/watch?v=X8Z7veGV57o
There are tens of thousands of BNCs on oscilloscopes and other instruments and
I've seldom had an issue with them in 30+ years of lab work. For quick
disconnect I also use short jumper cables with BNCs to break the connections
between the hardline running to the tower and the cable entrance to the shack
during lightning season. Admittedly, I'm only running 500 W. When I can leave
them more permanently connected I revert to type N.
Wes N7WS
On 9/17/2018 5:04 PM, [email protected] wrote:
If you have a vector network analyzer you'll discover that BNC
connectors aren't all that great at VHF and above, l oss and
impedance vary with connector axial alignment because the bayonnet
shell doesn't support aligh the connector body very well. Strain relief
is extremely important with BNC connectors. TNC connectors are
far superior but not widely used.
While professionally installed N connectors have superb RF
characteristics, all too often they're improperly installed -- even by
professionals -- leading to damaged connectors if the male pin is
misaligned, or unreliable contact if the pin or socket depth is just a
few millimeters less than the manufacturers specification. I use
only captive pin male N connectors, avoiding the most severe
problems. I never use female N connectors on cables, the N sockets
are much too fragile.
Its hard to beat high quality silver plated UHF connectors at HF and
6 meters. But its important to use a tool to tighten them. That's a
small price to pay for a very reliable connector.
73
Frank
W3LPL
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