On Thu, 2008-05-08 at 18:18 -0700, Denton wrote:
> Since I don't run an afterburner, I typically use bnc connectors on just
> about everything, if anything for ease of disconnects/connects. I got that
> idea from a broadcast engineer. I know they are only good for about 1000
> volts, but wonder what their loss is compared to uhf connectors?
> ----- Original Message -----
Unless I happen to make or have a UHF to BNC cable, every radio in my
shack with a UHF connector has its own dedicated UHF to BNC adapter.
Their loss is fairly low, and the impedance is 50 ohms unless the
thinner center pin for 75 ohms is in use which tends to not mate with a
50 ohm center pin. The shield connection is a springy ring with four
splits that mates with a slightly tapered female outer connector. There
is where the BNC beats the UHF.
Though at real UHF frequencies, BNC is not liked for measurements
because the bayonet ring doesn't support the connector as solid as the
threaded ring of the TNC or N connector. The TNC is the same RF
interface as the BNC with a threaded ring instead of the bayonet ring.
That poorer support in the BNC shows up as inconsistent impedance and
leakage measurements.
There do exist BNC connectors for RG-8 but they aren't common and are
fairly expensive. That size coax probably will break those connectors
unless independently supported.
I've come to like the Amphenol FCP family of UHF and BNC connectors for
cables because the center pin is well anchored and so is the braid under
a spring clamp. I think the assembly is as strong as a crimp, but needs
no crimping tools. Amphenol 31-4700 for 50 ohm coax.
73, Jerry, K0CQ
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