I have a chance to buy an Explorer 40-foot telescoping tower, which from
the very brief description I have sounds like it might be useful for Field
Day and CAP exercises, but I can't find anything on the net that describes
it.

It comes with something called an "undertire" mount, which I assume means
a tower base with a plate onto which you drive the tire of a vehicle and
park it there, to hold it down.

I googled "Explorer tower" and got nothing. The owner reports he bought
it from AES but there isn't anything about it on AES's website either.

Anybody know what it might be and where on the net I might be able to find
some information on it?

Thanks...

Rick (W-A-one-R-K-T) wrote:
I have a chance to buy an Explorer 40-foot telescoping tower, which from
the very brief description I have sounds like it might be useful for Field
Day and CAP exercises, but I can't find anything on the net that describes
it.

It comes with something called an "undertire" mount, which I assume means
a tower base with a plate onto which you drive the tire of a vehicle and
park it there, to hold it down.

Exactly... but don't expect it to stand up to much wind load
40 foot lever arm on a 1 foot plate, and it's pretty easy to lift the
tire off the ground.

I've found that some form of tripod and some shot/sand/water bags is an
easier field expedient (because you can put it anywhere... you don't
have to be right next to the car).



I googled "Explorer tower" and got nothing. The owner reports he bought
it from AES but there isn't anything about it on AES's website either.

Anybody know what it might be and where on the net I might be able to find
some information on it?

Thanks...

On Tue, 07 Aug 2007 08:37:46 -0700, Jim Lux wrote:

Exactly... but don't expect it to stand up to much wind load
40 foot lever arm on a 1 foot plate, and it's pretty easy to lift the
tire off the ground.

Actually I was planning to use it with my motorhome, under the rear
tire... good luck getting THAT tire up off the ground.

Still need some info on the tower / mast, though... unfortunately the
owner is 120 miles away from here so I can't just drive up there and take
a look...

Rick (W-A-one-R-K-T) wrote:
On Tue, 07 Aug 2007 08:37:46 -0700, Jim Lux wrote:


Exactly... but don't expect it to stand up to much wind load
40 foot lever arm on a 1 foot plate, and it's pretty easy to lift the
tire off the ground.


Actually I was planning to use it with my motorhome, under the rear
tire... good luck getting THAT tire up off the ground.

One might think so at first glance, but here goes with a short scenario
(I was looking at using the roof rack on my car to stabilize a portable
mast)..
http://home.earthlink.net/~w6rmk/antenna/mastcar.htm has details..

40 ft mast 2" in diameter in a 80 mi/hr wind has a moment of 2200 ft lb.
if the distance from fulcrum to tire is 1 foot, then the up force on the
tire is 2200 lb.

So, your RV won't be lifted up, but my 3000 lb car would.

And, of course, if it's only a 40 mi/hr wind the load is 1/4, etc.

In practice, most people use a fairly lightweight mast and let it fail
before it damages the car.

Rick wrote:

I have a chance to buy an Explorer 40-foot telescoping tower, which from
the very brief description I have sounds like it might be useful for Field
Day and CAP exercises, but I can't find anything on the net that describes
it.

It comes with something called an "undertire" mount, which I assume means
a tower base with a plate onto which you drive the tire of a vehicle and
park it there, to hold it down.

I googled "Explorer tower" and got nothing. The owner reports he bought
it from AES but there isn't anything about it on AES's website either.

Anybody know what it might be and where on the net I might be able to find
some information on it?

Thanks...

Hi Rick,

Some years ago, I fabricated a 40' tiltup/rotatable mast from common 1¼"
plumbing pipe specifically for FD. Yes, it needs to be guyed (two guysets).
The mast supports a Cushcraft A3S 20/15/10m yagi. The top guys serve
double-duty as 80 & 40m inverted vees (80m is a 4-wire cage, and covers
nearly the entire band w/o a tuner).

Some metal fabrication is required (drilling & light welding) but it's not
too involved. A single person can assemble & tilt the mast up/down though
more hands makes it go faster. Some photos and a video clip are he
http://tinyurl.com/38v9wn (the video clip is the last thumbnail image). Let
me know if you need more info.

73,
Bryan WA7PRC