On 10/10/2011 9:58 PM, Michael Coslo wrote:
Taking a break from computers, I had an actual practical question about
an antenna. Sort of hypothetical, but maybe some practical use.

Situation:

Yard with a maximum antenna possibility of 100 feet. Height around 60
-70 feet.

All band is desired

in line with that, a decision to run ladder line (not window line)


Obviously, a tuner will tune the antenna.

But an antenna cut for somewhere in the 75 or 80 meter band is often
touted as a good length, around 130 feet for this antenna.

Is there an advantage to loading the antenna to place it in the band,
and tune the rest, or just to string up in the available space?

Perhaps something to allow it to une easily on 160?

Or, is there anything that would contraindicate using this approach?

- 73 de Mike N3LI -

In theory, for 80m use, I don't see much benefit to cutting it exactly
for 80m. The difference in matching loss should be fairly unnoticeable
as long as you are in the general ball park.
Ladder line should be pretty low loss, even with a high SWR.
So if there were to be excess loss, it would likely be the tuner.
And in this case, I don't think the difference would really be
noticeable on the air.
But... If it were me, I'd probably cut it to length anyway. But only
for the reason that I might decide to use coax at some later
date, and could still use the same wire. Or.. at least make it
too long, not too short.. That way it could be re-used with any
kind of line. But, maybe I'm just overly cheap and hate to see
a perfectly good stretch of wire go to waste.. :/

For 160 use, I'd feed it as a single conductor. Either short the
feed line, or feed just one leg. I'd generally prefer to short the
feed line to add more top loading. Makes it act like a T vertical.
If you fed one leg, it would be like an inv L. Either way should
be easier to match with a lower loss than trying to feed it as a
1/2 size dipole. The tuner loss will get you in most cases trying to
do that.