Hello again Bob,
See my long answer to your other message.
RD> Are there any designs for 160 and 80m Richard ?
Yes. I mentioned one in the other message. I'll expand on that here.
A 40 foot push-up TV mast like Radio Shack sells is ideal for the job.
The lower end does not have high voltages on it so it can be bracketed
to the house with regular TV mast brackets. I'd put a split piece of PVC
pipe between the mast and the bracket clamp. The bottom of the
mast can be buried about 6 inches into the ground to hold it in
place. Radials if possible would be good if not a short connection
to an outside faucet, not more than a couple of feet distant. Attach a
#12 wire (and solder) to the top of the mast. Run the wire down the side
of the mast with at least 6 inch spacing but not much over 12 inches or
so. Space using something like TV stand-off to keep the wire evenly away
from the mast. Feed wire from L network. Depending on local ground and
frequencies used the feed point will at times have very high RF voltages
even if you run low power.  This antenna is very effective on 160 and
80/75 meters---also does well on 40 meters although it is a "tad" long
for this band. Which means the matching will be a bit touchy.
RD> If I wanted one for operating on those two bands what
RD>rough size would the antenna be ?
Use the same antenna for both bands and even 40 mtrs. Change only the
matching. Caution: the lead-in from antenna to matching network is part
of the antenna and can have high voltage RF on it. I mean high enough to
curl your hair.
RD> I'm using a trapped dipole on 160 and 80m now and the idea
Verticals are not very good for close in contacts due to radiation
angle. We are talking real DX late at night or dawn. Dipoles are for rag
chewing with locals on the lower bands. Pays you' money and takes you'
choice.  Or put up both types of antennas---if you have that much room
to keep them well separated.
RD> If the folded dipole antenna were a full wave-length
RD>antenna (folded) would it work the same as a folded 1/2 or
RD>1/4 wave-length antenna or better?
Good grief! That is not a simple question.  The answer is an
unconditional YES in all cases except where the answer is NO. You are
playing with different radiation angles which affect who you wind up
taking to and all kinds of tricky antenna matching widgets which can
easily waste any possible advantage from a superior(?) antenna.
73,
Dick, W0RPV
 * SLMR 2.1a * Dyslexia can warn without striking!
--- Maximus/2 2.01wb
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