I don't see what the mechanism would be for the 0.7 - 0.8 dB loss you
quote, even if the connector has a rather poor dielectric. And one with
a good dielectric like Teflon wouldn't have any way to cause loss other
than conductor skin effect resistance. If anything, I'd expect an N type
connector to be slightly (although inconsequentially) lossier due to its
smaller diameter center conductor.

What reference do you have that shows this kind of loss for a PL-259?
I'd like to look at the test methodology. I'd also like to hear some
kind of explanation as to why an N type connector should have less loss
than a PL-259.

A PL-259 will of course cause a greater reflection than an N type
connector, and this will produce a "mismatch loss" in a system, like a
lab test environment, where the source and load impedances are fixed.
But nearly any amateur antenna installation has some method of adjusting
the match to compensate, which eliminates power delivery reduction due
to mismatch. Then, only true loss is important, and I just don't see the
mechanism which would cause a PL-259 to be any worse than an N.

Roy Lewallen, W7EL

matt wilson wrote:

"Ken Bessler" wrote in message
news:uS7jd.15068$Vz4.14651@okepread01...
I'm aware that the PL-259 has loss but what I'd
like to find out is how much loss at 146 & 450 mHz?

Anyone know?

Ken KG0WX

It depends on a whole lot of factors, not least of which is the quality of the
connector and how accurately it is assembled. For 70cm, losses are typically
around 0.7 - 0.8 dB. This might not seen like a lot until the number of
connectors is added up.A base station with a main co-ax run, a socket
terminated antenna, and 2 co-ax tails has 4 connections. That adds up to 3dB,
or half your signal lost before you even look at the co-ax losses. By
comparasion, a quality N-type is less than 0.1dB.

On Sat, 06 Nov 2004 16:35:44 -0800, Roy Lewallen
wrote:

|I don't see what the mechanism would be for the 0.7 - 0.8 dB loss you
|quote, even if the connector has a rather poor dielectric. And one with
|a good dielectric like Teflon wouldn't have any way to cause loss other
|than conductor skin effect resistance. If anything, I'd expect an N type
|connector to be slightly (although inconsequentially) lossier due to its
|smaller diameter center conductor.
|
|What reference do you have that shows this kind of loss for a PL-259?
|I'd like to look at the test methodology. I'd also like to hear some
|kind of explanation as to why an N type connector should have less loss
|than a PL-259.
|
|A PL-259 will of course cause a greater reflection than an N type
|connector, and this will produce a "mismatch loss" in a system, like a
|lab test environment, where the source and load impedances are fixed.
|But nearly any amateur antenna installation has some method of adjusting
|the match to compensate, which eliminates power delivery reduction due
|to mismatch. Then, only true loss is important, and I just don't see the
|mechanism which would cause a PL-259 to be any worse than an N.

I second Roy's comments.

The "UHF" connectors have many drawbacks: they are not constant
impedance, they are not waterproof, their mating is not repeatable and
they are difficult to assemble; however, they are not necessarily
lossier than other types.

It is difficult to prove this in a lab environment because there are
no traceable reference standards for this connector series. Thus,
between-series adapters are needed to measure them and adapters always
add uncertainty to the results.

Clearly though, by inspection it can be seen that for decent quality
materials and construction, there is no inherent loss mechanism that
would result in the highly inflated loss figures commonly bandied
about in ham radio circles.

Wes N7WS