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Author Topic: lube to use when pulling coax  (Read 12281 times)

Posts: 2256

« Reply #15 on: August 24, 2012, 04:53:04 AM »

Personally, I prefer to use multiple transmission lines in most instances.  I can have several radios on at once, each on different bands.  A switch is useful in certain situations, and a good one will prove reliable.  I have a very nice 4 position Transco switch that is currently not in service, but I plan to use it again shortly in a V/UHF antenna configuration.

Have you tried a test "tug" yet?  You may find that it easily transits the pipe?  Again personally I'd avoid putting water in there at all costs.  I do my best to ensure the pipe is as dry as possible.

One other thought.  If you pulled your multiple lines together in the beginning, they no doubt corkscrewed down the pipe as they went along. So now your "cables" have a gentle twist around one another as they lay in the conduit.  As you pull out the old one with the new one attached to the end, you're going to have to follow that corkscrew around the existing cables.  I'm a big proponent of pulling one "cable" at a time, be it coax, or a control cable.  Doing so prevents the bundle from twisting around one another and allows easy removal.  I leave no pull lines for future use in my 160' run of condiut.  Rather I blow a "ghost" down the pipe for each new run.  The ghost is very rudimentary and is not a commercial one.  It's merely a plastic grocery bag scruntched up and stuffed lightly in the the pipe with a mason's line tied to it.  I prefer to send the ghost down the condiut using the exhaust of a shop vac, but you can suck it down the pipe as well.  Either way, the thing goes down the pipe so fast that the line will burn your fingers if you're not careful.  Once the ghost flies out the other end, I proceed to pull the new line; no twists, no drag.  Each line is a straight pull.
« Last Edit: August 24, 2012, 05:04:18 AM by K3GM » Logged

Posts: 1757

« Reply #16 on: August 24, 2012, 05:07:45 AM »

If you're pulling the bundle out and not in, using the slick stuff in the past would not have made any difference. Once it evaporates, it's not much lubricant any more and it turns to powder.

My suggestion: Hook a garden tractor up to it and once it starts moving, don't stop. Stopping and starting is the hard part, keeping it moving is much easier.

73 de N4CR, Phil

Never believe an atom. They make up everything.

Posts: 9749


« Reply #17 on: August 24, 2012, 05:22:42 AM »

I am adding the "rat pac " from Array Solutions to remote and end up running just two pieces of coax and a rotor cable. NO one likes the water hose idea ? javascript:void(0);  John kb2huk

Ps: is there a high failure rate for remote switches ?

Properly built remote antenna switches, if they do not have semiconductors on the switch control lines, are very reliable. I have ten or twenty in my system and almost never have a problem. I don't even use lightning protection devices.

One of the only times I've had a problem was when an antenna connection failed and we transmitted with 1500 watts into the switch. Otherwise they are not issues at all.

Beware of switches that run RF along PC board groundplanes, when a top foil forms a transmission line. Normal G10 boards will get pretty hot on ten meters at 1500 watts on a normal stripline with the opposing foil as a backplane. The RCS8V and DXE switches use an air gap between the foil and chassis as the dielectric, and won't get warm even at a few kilowatts on 50 MHz. This (and no semiconductors) helps for reliability, including lightning immunity.

The mark of a good switch layout is any port can be used on any band without any SWR or crosstalk change.

73 Tom
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