I have the real world experience you're seeking.
Back in 1997, I built a full-size 40m 4-square with 60 ground radials per
element. It worked great, and beat the heck out of the full-size monopole
that preceded it. The directional capability is really terrific on receive
-- a full 20 dB F/B -- and switching is instantaneous.
However, a few years later I put up a 2-el Cushcraft 40-2CD on a 50-foot
AB-577 military surplus mast. I was able to do A/B comparisons easily, and
the beam blew the heck out of the 4-square on receive -- at least 10 dB
louder, sometimes more. The F/B wasn't anywhere near as good (something like
10dB), but in practice that didn't hurt me all that much. Sometimes when the
US QRM was bad on 40 I would switch to the 4-square to escape it while
receiving. On very rare occasion, the 4-square beat the beam on a low angle
paths, say to JA in the morning. But to EU, which is the bread and butter
for New England contesters, the beam reigns supreme.
My contest scores on 40 improved considerably after I installed the 40-2CD,
which to me is the proof of the pudding. I later moved the 40-2CD up to 70
feet and it performed even better relative to the 4-square. Finally, I moved
the 40-2CD to 110' on a guyed tower and it would sometimes show as much as
15dB louder than the 4-square on receive. It's not clear to me that this was
a reliable measurement of the difference, but relatively speaking it was
pretty dramatic.
A few years ago, I replaced the 40-2CD with a full-size 2-element Cal-AV
2D-40A. That antenna completely blows the 4-square out of the water -- the
S-meter difference can go as high as 20 dB. On transmit the full-size beam
is a killer, and once again my contest scores on 40 took a big jump when I
installed it.
Was the 4-square worth it? Well, it was a huge amount of work to install the
4-square. It took forever to measure off the radials and solder them to
copper rings (did that indoors over the winter.) I recall it took several
weeks to unroll the radials, pin them and solder the intersections (a
somewhat controversial practice.) The whole project took months. And it
wasn't cheap: I had to have about a half-acre of land cleared so I could
easily run the radials, and that was pretty expensive at the time (around
$1,200 -- now it would be a heck of a lot more.) I got my old Colatchco
controller very cheap from a friend, and paid some for new element tubing,
some new 70-ohm coax for phasing, some choke baluns a dummy load and a power
meter with a remote coupler. I don't recall the exact cost, but it was
probably around $2,000.
All that said, at the time I didn't have a tower capable of supporting a 40m
beam, so the 4-square was a great solution until I was able to get a tower
up. It allowed me to get in the game of DX contesting from W1, though it
didn't put me in the top group on 40.
Normally a tower would have cost a lot more than $2,000, but I discovered
the AB-577 surplus military mast and was off to the races. It's tricky to
raise one of those with a big beam like the 40-2CD, but it can be done
safely if you have three or four friends to help you.
Bottom line: a 2-el beam will beat the heck out of a 4-square. The gain of
the latter isn't much better than a dipole, though the directionality is
exceptional.
One more important bit of information: These days I use the beam and
4-square together in a Diversity receive configuration using my K3. That is
a totally killer combination, by far the best receive system I've ever had
on 40. Signals that can be barely copied on one antenna will often be clear
on the other antenna. Static crashes and QSB don't hurt kill copy like they
used to. I can quickly switch the 4-square to copy a station off the back
while still transmitting. It's a phenomenal setup. So, in that sense, I'm
really glad I have the 4-square!
Hope this helps.
73, Dick WC1M
> -----Original Message-----
> From: John Frazier [mailto:fraz1@bellsouth.net]
> Sent: Saturday, September 29, 2012 3:42 PM
> To: towertalk@contesting.com
> Subject: [TowerTalk] Experience with phased verticals on 40m?
>
> Anyone have real-world experience with phased verticals on 40m? Actual
> comparisons to high dipole, etc would be greatly appreciated.
>
> Bottom line...was it worth the effort?
>
> 73 John W4II
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|