Sorry if you've seen this before, but I posted a similar question in the
antennas group last week. Unfortunately, I think they're too busy arguing
reflection coefficients, and I only got two replies. Since our station will
use all vintage Swan gear, I hope this is on-topic enough for this group.

I'm building a new ham shack for my company's radio club, and I would like
to hear some suggestions from our group about what antennas would be best
for our location. Here's some details:

We want to provide for all HF bands first.
Maximum power will be about 500 watts, all-tube gear.
Location is San Diego, CA, USA.
The shack is at ground level, immediately against a two-story building with
a concrete & rebar curtain wall about 50 feet high.
The top edge of the concrete wall is about 6 feet above the building roof.
The building roof is a flat metal pan, about 300 feet by 300 feet.
We have a BWD-90 160 M through 6 M folded dipole.
We have an IAC 40 M Double Bazooka antenna.
We have about 1000 feet of RG-213U coax.
We do not have a remote antenna match network.

We plan to place the folded dipole about 6 feet above the edge of the
concrete wall, running N/S, to initially get us on the air.

The Double Bazooka might be strung NW/SE, to give us a maximum lobe toward
the rest of the US & Australia.

So, what should we do next?

A long-wire is one possibility, but we can't get much more than about 10
feet above the metal pan on that building roof.
Perhaps a horizontal loop, standing maybe 8 feet above that pan, for NVIS?
Perhaps a vertical multi-bander (what a ground plane!)

What would you do? Comments & suggestions appreciated.

Thanks,

Ed
WB6WSN

Good morning, Ed.

If you can't put up a beam, then I'd say that your multiband folded
dipole and a multiband vertical will give you very good performance.
Since you already have the double bazooka antenna, stringing it NW/SE
as you suggest would give you another option, but I wouldn't go out
and buy one if you didn't already have it.

The folded dipole 6 feet above the top of the concrete wall might give
you good NVIS coverage depending on the action of the rebar in the
concrete (not sure about that).

73

Rick WA1RKT

"Dick Carroll;" wrote:

Ed Price wrote:


Perhaps a vertical multi-bander (what a ground plane!)

This is an easy choice given the ground plane, if you can guy it with Phillystran you're
in business. I still remember using an old Mosley trap vertical on the
galanized tin roof of a garage 35 years ago. Worked like gangbustgers.

Dick

Way back in high school, our school radio club used a Hy-Gain 18HT HyTower up on a 3rd story
metal roof. Worked wonderfully! MFJ has reintroduced that antenna with a few improvements.
You might look into it.

Wayne Faris, KE0BZ



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"Dick Carroll;" wrote:

This is an easy choice given the ground plane, if you can guy it with Phillystran you're
in business.

That'll work well for DX, not so well for close-in work out to about
200 miles or so on 80/75/40. For that you need a NVIS antenna.

He seems to have enough options so that he can install both.

By the way, what is Phillystran?

Rick WA1RKT

wrote:

"Dick Carroll;" wrote:

This is an easy choice given the ground plane, if you can guy it with Phillystran you're
in business.

That'll work well for DX, not so well for close-in work out to about
200 miles or so on 80/75/40. For that you need a NVIS antenna.

He seems to have enough options so that he can install both.

By the way, what is Phillystran?

Rick WA1RKT

An interesting substitute for "Phillystran" is the old "all plastic and glass" fibre optic
cable used for some networked computer installations. The strength member
is usually Kevlar. Good insulation and high strength.

Bill K7NOM