RG-8x Coax Cable Jumper...

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Jack Ritter:
RG-8X is commonly used for jumpers between transceivers, coax switches, low pass filters etc.  I built a matrix of nine coax switches feeding two additional rig select switches (Xcvr 1 and 2) used to select antennas 1-9 plus a remote coax switch which delivers five 160m slopers to the rig. Keep the jumpers as short as practical; between 160 and 10m you should not experience difficulties running QRP to legal limit.

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Dwight,

It is absolutely fine to use 8X as jumpers in the way you describe.  Even at UHF frequencies, the differences in loss between 8X and it's larger brothers is insignificant for "jumper" lengths.

I would hesitate to use 8X at high power levels -- like above 500 Watts -- but that's just my personal preference -- I want a little more dielectric between the center conductor and the braid at high power levels than 8X offers.  

A few words of other advice.  Use a quality brand of 8X that has 95%, or greater, shield coverage.  There is some real crap stuff being sold out there.  Rat Shack cable is NOT worthy of your time and money.  And, realize that there is loss in each and every connector, adapter, switch, etc that you put into the circuit.  Not a lot, but, especially at UHF, it does start adding up, so keep them to a minimum.  Use quality connectors too.  I've fixed dozens of repeater desense and other system noise problems that were caused by either crappy quality cable or some of the garbage connectors and adapters that are being sold at hamfests and places like Rat Shack.  

Larry J. Rolewic:
RG-8X from a REPUTABLE MANUFACTURER, should be suitable for jumper cables.  But be sure to use a good quality cable, not the stuff you get at the local "Nationwide Chain" store in town.  It pays to get GOOD quality cabel, such as Belden, Times Microwave LMR series, or similar.
    And I would NOT use it for high power, despite what is said.  Previously it was stated that it would operate 1800 Watts @ 160 M.  The voltage rating on this cable is 300 Volts.  at 1800 Watts, into a PERFECT load of 50 Ohms, you would be AT the maximum working voltage.  At 1500 Watts, with a mismatch, you could easily exceed the working voltage with unpleasant consequences.  I wouldn't use that size coax for anything more than a couple of hundred watts, and then only for jumpers that are protected from physical abuse such as being stepped upon, bent sharply, etc.
    If your jumpers have ANY possibility of such an occurrence, you should use RG-213/U (solid dielectric) coax cable; you may even need to use both types of cable in your installation.  (But it's best NOT to have any cable where it can be stepped upon, tripped over, etc.)  And if you have to make sharp bends, it's really better to buy a few (good quality) M-359 right angle adapters than to stres the coax.  This is especially true for foam insulated coax such as RG-8X.

Good luck.

tom lish II:
I use rg8x for aslmost everything.  I try to keep my hf runs to 100 feet or less and vhf to under 50 feet and uhf runs as short as possible.  I am currently running a 4 band rotatable dipole at 70 feet long, a 5 ban vert, about 20 feet away, a 40 meter dipole and an 80 dipole at about 40 feet away, a 10 meter antron 99 vert at about 60 feet away, and a AO-40 set up 440 up and 2.4 ghz down at about 30 feet all on rg8x.


the db loss goes up with the higher freq's. and longer distances.  go to belden.com and down load their table for coax loss.


I have my ma5b  feed with rg8u, because I had some.  I buy rg8x  on ebay for $87 for a 500 foot roll delivered. I can afford to play and use this all day.  I even have some 58u here, got a  500 foot roll for $60 bucks delivered.

My amps don't go over 1000 watts and 8x will hold this on hf,  I don't do more than 300 or so on vhf/uhf and it works there too.

I would probably gett a little better signal using 213 or something but this is a hobby, and 8 x is cheep.. and it works  73  tom

William H. Albert:
I also bought my RG8-X off of Ebay. I have been using it for over a year now with no problems.  The stuff on Ebay is made by TRAM and is called "TramFlex" it has a 95% shield and is very flexable for mobile work.  I just bought another roll of 500' and it was $87 WITH shipping, that's 17.5 cents a foot. Not bad.

73,
Bill

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