We've been talking inferior UHF connectors here (especially angle ones)
and it doesn't require voltage breakdown ... current alone can do it.
Assuming a KW on a 50 ohm line, a resistance of 0.1 ohm will dissipate 2
watts, which is enough in that tiny spring to affect it and potentially
cause an arc ... especially since any shift could easily cause
additional resistance. Maybe an insertion loss test sees something 27
dB down ... maybe not.
Dave AB7E
On 11/25/2023 11:51 AM, Scott Townley wrote:
If that's the case, then wouldn't an insertion loss test reveal such
an issue?
For example, I was deconstructing the power handling of a Charter
Engineering B5-series coaxial relay (N-female connectors). If I map
"max insertion loss at x GHz" to the average power rating on their
published chart, at every point the dissipated power comes out to 11
watts. That tells me that "good" N-connectors can dissipate 5 watts,
and for that mechanical form factor I should be able to derive a power
limit based on measured insertion loss.
Or are the physics of power handling in "not-so-good" connectors
different from what would be revealed by an insertion loss
measurement? Assuming of course that we are not in the realm of high
voltage breakdown of the dielectric (or maybe that's exactly the
difference?).
On 24/11/2023 17:29, Jack Brindle wrote:
One of the big problems with off-brand connectors and adapters is
their power handling capabilities. This is especially noted in the
right-angle adapter. We see a lot of arcing when higher power is
applied.
Higher power in this case is anything above just a few hundred watts.
Whenever I see an amplifier log report with a lot of high reflected
power or PA Dissipation faults, I immediately start looking at the
connectors and feed line for problems. These are usually found in one
of several places - right angle adapters, and baluns that were meant
for low power, but have been over-stressed with high
power.
My advice? If the right-angle adapters aren’t Amphenol, throw them out.
73,
Jack, W6FB
On Nov 24, 2023, at 12:59 PM, Scott Townley <scott@nx7u.net> wrote:
Say I have a pile of coax adapters on my bench (we all do, right?).
How do I separate the wheat from the chaff? I have a fully equipped
bench...I would think the go-to would be a TDR measurement. Any
better/additional suggestions?
TIA,
--
Scott NX7U
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