Hi Ian,
> The term "UHF" is a complete misnomer in discussing these connectors. They
> are strictly HF devices. VSR above around 140 MHz is too high. The better
> types use PTFE, bakelite or similar insulation (won't melt when heated
> with a soldering iron).
The impedance bump in a UHF connector is confined entirely to
the area of the female about 1/2 inch long, assuming a hood is
used on the female's rear. The impedance of that bump is about
30-35 ohms.
The VSWR error from using a single connector, assuming the 30
ohm impedance and a VP of .5 is 1.028:1 at 50 MHz.
It is only 1.25 at 400 MHz!
That's why you find UHF connectors used on landmobile radios up
to 400 MHz and higher. The impedance bump, and loss, of a UHF
connector can be pretty much ignored up to 250 MHz, and often is
negligible above 250 MHz if the connector has partial air dielectric
in the female section.
73, Tom W8JI
w8ji@contesting.com
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