Michael Lawson wrote:

"Mark S. Holden" wrote in message
...
Michael Lawson wrote:

I have a confession to make; I've always wanted an outdoor
antenna, but I was never either allowed to (when I was a kid)
or wasn't pratical do run one. Well, I now have the ability
to run one outside, but there are some questions I have about
some of the gagetry that is available these days.

Since I'm planning on running a random wire until I can figure
out a more permanent location for a trap antenna that I'll
build (assuming that I still have that old article from Pop Comm
(or was it Audio?) lying around), I'm not so concerned about
the antenna itself as some of the other goodies.

First, the coax. I noticed that Rat Shack was running a special
on their RG-58U coax for $0.11/ft, but I also know that RG-8 is
has better attenuation numbers. My run of coax is about
60-70 ft or so (at least initially, I'll probably remove some of
the built-in slack in my estimates once I'm satisfied with where
the antenna will be). Should I worry about attenuation for the
HF bands enough to use the RG-8 over the RG-58??


Personally, for receiving, I'd be more concerned about using radio
shaft
brand coax than the difference between RG-8 and rg-58.

Last I knew, their coax wasn't very well shielded.

I went poking around the net for a while trying to
find out whether it's worth it or not, but I couldn't
find anything on the quality of the cable there. At
least any real data, that is.


It's years since I bought RS cable, IIRC, the shielding was loosely spiral wound instead of a full braid.

A fair number of people use RG-6 - it's 75 ohm impedance, but the losses aren't likely to be meaningful. Home improvement stores tend to sell quad shielded RG-6 at a reasonable price.

The way I see it, noise is the limiting factor - so I'll gladly trade a few db of signal strength for several db of noise reduction.

Second, a lightning arrestor. Are those Alpha Delta Transitraps
as good as advertised, or should I stick with a regular gas
discharge variety??


I use a polyphaser - it works well. Couldn't tell you about the
others.

Thanks for the info.

Third, has anyone run an external antenna to their Sat 800?? I'm
curious as to your setup, since it's a plastic case and the old
ground connection that I was used to on my old Icom R-70
isn't around, so I was wondering if anyone bothers to try to
ground the outer jacket of the coax. (Yeah, I know that that
ground on the R-70 was for the casing, and that this means we'll
open a can of worms here, but I figure I'd ask anyway.)

My advice is to use an impedance matching transformer, and ground
the
coax by the antenna.

I was planning on using my MFJ antenna tuner to perform the
impedance matching for the random wire, but I can see your
point of wanting to do that at the transition point. Any decent
ones around?? That MLB one seems to have people in either
love it or hate it camps.

--Mike L.

I wind my own impedance matching transformers. It's easy. They work well, and you don't need to twiddle knobs.

You need a few feet of magnet wire, and a #43 ferrite core. Here's a link to a site with directions:

http://www.kc7nod.20m.com/new_page_1.htm

I recently bought over 100 #43 ferrites that are a little smaller than the one in the plans, but they work fine. If you need one, contact me direct - I'll sell you one for a buck postpaid.