K3VAT <<I would avoid any type of end fed antenna; I know, they're some good reviews here on eHam.net, but are in fact no competition to a dipole.>>
Ah, its the same antenna.. The only difference is the feed point. Both are resonant antennas
and both are half wave. I did specify an end fed half wave. If you use the PAR/LNR design
you do not need any additional matching network. I happen to use a PAR EF40/20/10,
and an EF40, never had RF issues at power level up to 100W for the 40 and up to 50W SSB for
the 40/20/10. I use the 40/20/10 here with one end supported by a 30ft tower to a tree
(flat top) and my other one is the one I drag to everywhere including two field days. If the
PAR/LNR price puts you off its a very easily home made. AA5TB has multiple write ups on this at http://www.aa5tb.com/efha_wrk.html
One note.. the wire must be a electrical half wave and not just nearly a half wave (resonant)
or the end result is a random length long wire with random results usually including RF issues.
There are other non resonant designs (26, 43, 88ft long) for end fed wires out there that might
present problems like needing a counterpoise and lower effective gain. I tend to not suggest them.
They are popular for multiband use at high power where one wire is it and compromise is tolerable.
I'd also vote for a standard half wave center fed but for a few reasons. One if you have a single
point mount where you support the coax. Remember it is best to have the coax leave the
antenna perpendicular for at least a quarter wave. If you bring the coax back to the point of
origin of one of the support points it is then parallel to the one leg of the antenna, not good.
If you are under the antenna great. If you are not that means at least 16ft of additional coax
to haul around. Also it is much harder to hang a centerfed half wave dipole vertically and
meet the requirement of keeping the coax away and not parallel. As a V fed at the balcony
and the ends tied off on the ground far enough apart may work. However its signal is blocked
on one side by the building and likely a metal one or containing metal or foil.
A twinlead Jpole for 20m is the same antenna save for its roughly 49ft long and its still an
end fed half wave with a transmission line stub transformer match. Not recommended for
Long wires work but the main issue is needing an adjustable tuner to match them and maybe
a ground/counterpoise to work against. Advantage is they are multiband, usually. Disadvantage
more stuff and long. Since you are doing 20M PSK31 this approach may not be any advantage.
The breem/crappy/fiberglass outrigger pole is the collapsible fiberglass pole that is often use for
portable work. What works nice is if a end fed half wave wire can be run up the center and
the pole is long enough. I have one that's 20ft I use for 10M (wire is about 16.4ft) and
the match box is at the end. Shrinks to less than 4ft in minutes. For longer wires there are longer versions or it can hang off the end as a sideways L.
Whatever you do try it or several at home and get used to how they tune and what you need
to make the selected antenna work at the site. Bring rope or 5/50 (paracord) as it's handy for
this kind of field work.