Hi Tom.

Don't listen to the purists.  When you are dealing with a piece of coax 
that short, the losses are insignificant.  You could even get away with 
running RG58u in a 20 ft. length.  Some people don't use their heads.

I'd leave the '8X on and go with it--you'll never ever notice the difference.

73, de Lou K2LKK



At 08:19 AM 5/22/2006 -0400, you wrote:
>Hi, all.
>
>I am finally making progress in terms of getting my new HF Predator
>screw-driver-type antenna installed onto my RV travel trailer.  Hope to have
>it done by this week-end. ... My question is this:
>
>The person helping to install the antenna has already put Belden RG8X coax
>on the antenna.  The coax run will be about 20 feet, going from the back of
>the trailer to the inside where I'll have my Icom 718 HF rig.  We will have
>the coax running in a PVC conduit which will run along the frame of the
>trailer, and the coax will come up through a hole at an appropriate spot
>inside the trailer.
>
>Someone has suggested to me that I really ought to be using thicker coax for
>this purpose, in order to minimize loss.  I do have a 100 foot chunk of RG8U
>coax with a foam dialectric that I could get the needed coax from, but don't
>want to go to all the trouble of re-doing the already-existing connections
>on the antenna if it really won't make much difference.
>
>The guy who installed the original coax on the antenna looked Belden RG8X up
>in the ARRL antenna book, and found that it has .7 DB loss per 100 foot on
>10 mhz, so any loss for a 20-foot run would seem negligible to me.
>
>Am I ok here, or should I really consider the thicker RG8U stuff?
>
>I know there are likely to be a variety of opinions on this one, and I
>suppose I could always change coax runs later, but I want to try doing
>things right the first time if possible.
>
>Thanks as always for your very helpful advice.
>
>73 from Tom Behler: KB8TYJ

Louis Kim Kline
A.R.S. K2LKK
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