The quick story... circa early mid 1980's
Motorola had just put a brand new 800MHz trunking
system on the air from above San Jose on Monument
Peak with what appeared to be really numb receivers.
.... an $80,000 boat anchor...
A group of us mountain top types were called to
fix the problem. The local famous Paul M. walked
right up to the rx combiner and started pop'ing off
the round body right angle elbows and replacing them
with the newer square body units spec'd for operation
to at least 1GHz and higher.
The common high tech brand name round body right
angle elbows were horible impedance bumps at 800MHz.
Don't know much about their physical construction but
I have seen connectors with springs for conductors,
which I know can't be good news.
After the elbow and a few connector swaps the trunking
system came to life... seems Paul had run into this
a few time before and had a large bag of replacements
handy. He also had a network plot of many common
connectors, which wasn't pretty or encouraging for
uhf and higher operation.
I don't trust off brand connectors without verification
and I like to use as few of any type connector as
possible. I've found low cost coax connectors and
adapters with not so hot D-factors and hydroscopic
issues. So now I pay more attention to the details
where possible.
Life goes on...
cheers,
skipp
> Bob Dengler <[EMAIL PROTECTED]> wrote:
> Did the round body N elbows have a solid inner shielding
> ring on the male side (as opposed to the split-finger
> style)? If so, these are actually made for microwave
> use up to 18 GHz. They do work down to DC of course,
> but the mating tolerances with the female side are more
> critical because there is much less spring action with
> the solid ring. I found in some cases that if the
> connector wasn't wrenched down tight, a deep resonance
> showed up just below 1 GHz. Sounds like maybe that's what
> happened in your case.
> Bob NO6B
>
> At 1/11/2006 02:38 PM, you wrote:
> >Everything depends on everything Bob. I've seen some
> >poor quality N elbows that ruined an 800MHz trunking
> >system (round body type). Replacing the round body
> >elbows with the better made square body N-Elbow brought
> >the trunking system rx pre-selector back to life.
>
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