On Thu, 25 Sep 2003 19:52:25 +0200, "Pjotr"
wrote:

Hi,

Any one good or bad experience with the Hy-Gain AV640? What about the
mechanical construction?

I *just* came in from setting one up on an 8' support to check the
settings.

My impressions:

It is well constructed and rugged. The aluminum tubing is of a heaver
stock than any I've seen so far in multi band verticals. It is
sturdy. You can support it horizontally from one end with no more
droop than the much shorter elements on a triband beam.

The metal hardware is well constructed. It uses stainless steel hose
clamps to clamp the tubing. The antenna to mast clamp is large enough
to handle a wide range of masts up to at least 2".

Make sure to get the holes in the stub insulators lined up. doing the
assembly on a flat floor or driveway should be sufficient.

I've only had a chance to do a very fast check. All bands but either
17, or 12 meters...(I said it was a quick check and I don't remember
which band) show very low SWR over the selected portions except the
one. I have made no adjustments from the original settings in the
dimension chart.

If you use the proper figures and only use the text as a guide the
assembly is easy and can be done by one person.

I'd either guy it with nylon rope, or use temporary guys to get the
thing installed. It can be a bit unwieldy and more than one person
would want to try to install alone. It is rated for 80 MPH wind
survival. However if installing it on even a short tower I'd guy the
thing as it'd put one terrible load on the top of the tower.

You can easily lift the thing with one hand, but not from one end.
:-))

Now as to the negative...Although the stub insulators are most likely
more than sufficient, I'd like to see them made of a bit heavier
material. They have the *appearance* of being a bit light.

I'd change one step during assembly. I would not install the feed
line connection box until *after* doing the counterpoise installation.
It gets in the way of tightening several of the screws, but it's not
impossible. Just an inconvenience. However know where you want it as
there is no counterpoise radial installed in that direction.

They don't tell you until the end that if you are not going to be
using the antenna on 6-meters you don't need to install the stub.
They should tell ham that when they are at the point of installing the
bracket.

I'd like to see them include a small tube of antioxidant grease
instead of suggesting you use some.

Once I'm though with the checkout, the antenna is coming down and
getting spray painted with a clear two part paint (Imeron) for
protection. Then it's going on top of a 32 foot tower at the end of
my shop.

I'll let you know how it works out.

Roger Halstead (K8RI EN73 & ARRL Life Member)
www.rogerhalstead.com
N833R World's oldest Debonair? (S# CD-2)

73's

Pjotr