Honestly, on HF for a short run like that, I'd say you're good with what 
you're doing, for short runs I'd say RG-8X is pretty good anywhere other 
than maybe UHF, the measurements in loss are done in 100 foot runs so like 
with my go kit, for the 2 meter side of things, I run the RG8X since most of 
my set ups are less than 50 feet, my packet setup runs it and I've tried 
both there and didn't notice much. If it's qualify coax which the brand you 
mention is, on HF, you're not going to notice any difference at all going up 
to a heavier coax. Fact is, with HF you could get away with RG8X anywhere 
and if you run 160 and 80 only, RG58 is good enough. Just the way the bands 
work.
----- Original Message ----- 
From: "T Behler" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Monday, May 22, 2006 8:19 AM
Subject: question about coax feed lines


> 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
>
>