Richard Clark wrote:
On Wed, 7 Apr 2010 20:09:56 -0700 (PDT), Tom Horne
wrote:

I am interested in having a rapid set up multi-band vertical for Field
Day and EMCOMM. If I use the Hy-Gain sixty four foot (64') push up
mast as the radiator and an ICOM AH-4 as the automatic antenna tuner
is this likely to be an effective approach to having a rapid set up
multi band vertical?

Hi Tom,

Yes.

Will I need radials?

Yes.

Which of course make rapid set-up somewhat less rapid.



Should they be elevated or
can they lie on the ground?

Yes.

Side route here, can be skipped to remain strictly on topic.

Ohh, Ohh! I can segue into my radials burying method. Banned in several
countries!

Beyond Richard's concise answer, Elevated radials are kind of a PITA,
and the stuff that neighborhood Antenna bans are based on. And for this
use, they are also going to be in the way.

I'd also note that one method of laying radials is easy, but not so
good. I tried laying half of my radials laying the lines on the ground,
held in place with ground staples. It works well technically, for
practical purposes, not so good.

Raking the yard is a great way to lift the staples and the rake pulls
the wires up also.

I'm a big fan of shallow trenching.

Now on to my trenching method......

All those years of organized sports have taught me many things-
Sportsmanship, Teamwork, Goal setting and achievement, and especially
how broken bones, pulled tendons, and ligaments can conspire to make
life a little painful as the years go by.

Anyhow, hand digging a trenches and laying the radials is really painful
for me.

And renting a professional trencher just goes against my Hamness, M R
expensive!

The following is a description of a method I have used, and not a
suggestion that anyone actually do this. As they say on Mythbusters,
Don't do this at home - are you crazy? Never use a tool for other than
it's intended purpose. Do not use sharp things - ever. You have been warned.

So my solution is using an inexpensive electric chain saw to do the
trenching with. Simply start at the ground plate of your vertical, and
dig a trence with the chain saw. Works a trick! Lay the radial wires in
and cover them back up.

This is needless to say, rather hard on the chainsaw blade, and probably
the chain bar.


I repeat, don't ever try this method. It's dangerous.

Since the total length of the radiator is
less than a 1/4 wave on eighty meters at say 3.6 MHz will that make
the antenna ineffective on eighty meters?

No.


Second question
5th, actually.
would four of those sixty four foot masts make an
effective forty meter four square.

Yes.

Yes I realize that it would cost
eight hundred dollars for the masts alone before the cost of
controller, remote, phasing coax, and control cable. Once again would
radials be required for forty meters.

Yes.

I've only been back in radio for a few years after very long gap so
I'm starting over and finding the learning curve a little steeper than
I remember.

You are still on the level wit the climb to come. There are a LOT of
details to make those simple answers work.

Back on topic


For emergency work, simplicity is mandatory. I see the idea of setting
up multiple masts and radials on location as an unneeded complication,
and a failure point as well.

I'd also be inclined to have different antennas for each use.

And while it's heresy in here, if you want ease of tuning (or complete
lack thereof), you might give some thought to a T2FD folded dipole
antenna. Not a particularly great antenna, but wide band, and you make
up for it's inefficiency by running legal limit power.

Otherwise give some thought to dipole antennas, perhaps a doublet, and
use an autotuner on it. A couple masts, amybe those fiberglass pole
types and you should be good.

If you really want directional power on 40 meters, look into a portable
mast and a 40 meter beam. Coupled with full legal limit power, you'll
make your own propagation!

I think that outside of a permanent EC command center, simple and quick
is the order of the day.

- 73 de Mike N3LI -