Dave, please see below! 73 de Steve WB2WIK/6
>Yes, I understand your point. Also, just wondering were you work? As to your
>application verses mine. At work we need a good, fast, and yet 100% foolproof
>way to do them. But, I don't agree you would get an impedance discontinuity
>with my way of installing them. At least when I sweep some of the cables I
>make for combiners I have not seen it being any different, the ID/OD ratio is
>basically the same either way. If you can keep from it, you don't use PL's on
>UHF anyway,<
::You're wrong about the impedance discontinuity. It's easy to measure.
Maintaining the same ID/OD ratio has nothing to do with this at all, even if it
were maintained (which it's really not). I assume you realize all the RF
current flows on the *inner* surface of the outer conductor of coaxial cable,
so it doesn't matter what the outside diameter is. Maintaining the outer
conductor intact until the cable bottoms out in the connector maintains the
impedance for about 1/2" to 3/4" longer on each end, and as that becomes a
reasonable fraction of a wavelength, this creates a larger and larger
discontinuity.
My cheap, fast, 100% foolproof way to install PL-259s is to use an automatic
stripper to prepare the cable end, screw the connector onto the cable four
threads, load four pasted solder preforms into the four body solder holes,
insert the cable/connector assembly into a soldering fixture in a 900W
resistance soldering station, and press the foot pedal. The four preforms melt
and reflow into the holes, through the braid, in about three seconds. Release
the pedal, apply compressed air to the connector for about five seconds to cool
it off, remove from fixture and go on to the next one. The entire
installation process for "production" work takes maybe 15 seconds, from the
beginning of the stripping process to the end of the compressed air cool-down.
Yields using a 2500V hipot tester (to check for shorts or near shorts) and then
a 300 MHz return loss sweep on completed assemblies are about 99.7%. We also
do a "pull test" on each connector, 30 lbs linear pull for 10 seconds,
prior to the hipot and sweep. The "equipment" all costs practically nothing,
if you're really in a production environment. The preforms etc. only work if
the connector bodies are *silver plated,* like Amphenol type 83-1SP. The whole
procedure doesn't work otherwise.
>At work we are using "DS" RG58 coax using center foam dielectric, not solid
>dielectric, (ours are mostly used on 800 MHz) and foam is very easy to melt
>when you are upside down in a Taxi cab. Some of our government installs are
>specked-out on exactly how to do theirs.<
::We never use cellular poly ("foam") dielectrics, ever. Reason is they fail
the 2500V hipot! But another reason is while surely lower in "loss," they're
also not as reliable or as mechanically robust. You can damage RG58 "foam"
cable by just stepping on it.
>At work we use "N" connectors on our RG213, 9913, 400 etc. 99% of the time,
>all our base antennas have "N". And we use crimp connectors most of the time
>with "N" or 7/16 DIN.<
::Good idea, crimps work best.
-WB2WIK/6
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