This focus on constant impedance reminds me of one-issue voters in
elections. Good engineering requires consideration of ALL of the factors
in a SYSTEM, and the relative importance of each.
About ten years ago, I made up a dozen or so 100 ft cables of low loss
coax (Commscope 3227) for a DXpedition, all using 83-1SP connectors. As
final test, I connected them all in series using Amphenol barrels and
measured the loss using HP gear. At VHF, it was less than the mfr's spec
for the cable.
Yes, we can run lots of power through cables like RG142B and RG400, but
have you looked at the loss data for these cables? In this respect,
they are equivalent to RG58! Their only virtues are size and shielding.
I'm using short lengths of RG400 inside my station for antenna switching
at HF and for common mode chokes, but I wouldn't dream of using long
lengths of it.
Nearly all of my station uses UHF connectors, and I use nothing but
83-1SPs. Type N's are on hard line, and when needed to mate with
antennas and equipment that comes with N-females, and I use the
wonderful single-piece Andros N male connectors on RG8-size cable.
Sadly, they seem to no longer be available.
73, Jim K9YC
On 4/30/2019 11:01 AM, Jeff DePolo wrote:
For starters, because it's constant-impedance (less of an issue on HF, but
definitely an issue on VHF and above), and is more weatherproof.
Type N has the puny bnc sized center conductor.
I'm not sure why you brought up BNC. Yeah, you can jam a type N male onto a
BNC female in a pinch and hope that it stays put, but BNC male and type N
male do not have the same center pin diameter.
A type N connector's pin diameter and the design of the interface handles
legal-limit current up into UHF. You can run 1500 watts through RG142B all
day and night on HF, and its center conductor has only about 1/3 of the
cross-section area of a type N center pin...and you're not going to fuse the
center conductor of either the cable or the connector.
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