> >off with a continuous run of coax than breaking the line
with a
> >connector, and inserting losses in the line. Which is
correct?
>
> I would do the math. If I knew the loss from the
connectors (say 1db for
> example), I would see if 200' of a rigid cable minus the
1db loss would be
> more beneficial than a single 200' run of a flex cable
with no connector loss.
I can shed some light on this, since I have the equipment to
measure this.
The loss of properly installed good quality connectors below
UHF is in the hundredths of a dB.
UHF connectors actually have less loss than N connectors
below a hundred MHz, and handle significantly more power.
The exception to this are some uncommon types of barrel
connectors and elbows that use spiral conductors and some
cheap plastic import connectors. Some of them measure as
high as .07dB loss, and are unusable at power over 300-400
watts.
The bottom line is if you use a good connector (even a UHF
type) below 100 MHz you can ignore connector loss or
mismatch. Above that frequency you should limit the number
of connectors if you use UHF styles, but type N's are
generally not an issue at all up to the GHz range.
Think of it logically. If the connector had only 0.1dB loss,
that's over 2% of the power. 2% of 1500 watts is 30 watts.
The losses are confined to about a 1/2 inch long area where
the extended male pin fits into the female.
How much HEAT do you think we would have with 30 watts
converted 100% to heat in a 1/2inch long area of connector?
How hot does a 30w soldering pencil get heating an inch or
two long area?
It's pretty plain to see that connector loss is another old
wive's tale of amateur radio.
What is the real issue? Reliability in the connections you
make. The more connections we use the more likely we are to
have a mistake someplace.
73 Tom
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