US Tower MA440 Plan?

[Joe Spinosa]

I'm new to this reflector, but it seems relevant to my situation.

I need to put up a modest (35'-40') antenna support structure for my VHF/UHF 
antennas.  I'm currently using a Cushcraft 13B2 Boomer on 2M and a 719B Boomer 
on 70CM (boom lengths approx. 16' and 13' respectively).  On top of that I 
have a VHF/UHF vertical.  All this is sitting on a Radio-Shack telescoping 
mast!

Please, I don't like that store any more than you do.

The mast bottom rests on a small metal spike driven into the ground (another 
RS product) and is bolted at two points to the side of an out-building.  I 
have 4 heavy guy wires attached directly below my Yaesu Rotator at about 25'.  
The whole thing seems stable, but I can't help wondering if this is a disaster 
waiting to happen!

I constructed the outbuilding as an astronomical observatory.  It's about 8' 
by 12'.  Since the gable roof rolls off to one side (so the telescope can see 
the sky), several design considerations had to be incorporated into its 
construction.  Suffice it to say that this is a small, but extremely rugged 
little building.  (It's built better than the house).  This is not a 
pre-fabricated aluminum shed or the like.

What I want to do is put up something like a real tubular tower as advertised 
by US Tower.  I am aware of what (I think) are the inherent disadvantages of 
tubular towers:  You can't climb them.  You need a 20'+ ladder to work on the 
antennas.  You can't easily attach things to the sides.

So why bother?  Two reasons:  Neighbors and the XYL.

I can deal with the neighbors, it's the XYL that's the real problem!  She 
doesn't think that antennas make a positive landscaping statement.  Can you 
imagine that?  Lately, I've come to believe that she really abhors my current 
set-up.  And yes, it is sort of Ugly!  It looks top heavy with all those 
antennas sitting on that skinny little RS mast.

This brings me to the meat of my problem.  US Tower says that their 40' two- 
section tubular only needs about a 16" square (or cube actually) base of 
concrete when the thing is "Properly Bracketed" to the eve of your roof.  
Otherwise, the base plug is considerably larger.  You can imagine what my XYL 
thinks of digging a 3'x3'x6' hole in the yard and filling it with concrete!  
In short, I don't think I could make that fly.

So how about it?  Can I pour a small footing for something like the US Tower 
MA440, Bracket the thing to the side of my sturdy observatory and use my four 
existing guy wires to make a safe and sturdy installation?  Or am I in fantasy 
land.  I wonder what US Tower considers "Properly Bracketed" anyway?

Two more points:  The walls of the observatory are only about 8' high (so that 
the scope can look near the horizon).  Therefore the bracket point would only 
be about 8' from the base.  I'm sure most "roof eves" are a bit higher than 
this.  I can modify the stud-wall construction of the observatory to beef up 
the bracket mounting point, or the whole wall, if need be.

In the future, I'd like to get more (bigger) VHF/UHF antennas.  (Those 
multi-wavelength M2 yagis look nice!)  I'm quite attracted to the weak signal 
SSB work at the bottom of the bands.  VHF can be like HF.

Any suggestions are welcome.

You can tell me to dig a big hole, but please don't tell me to get a new XYL!  
(Get her away from amateur radio antennas, and she's the sweetest thing).

Thanks,
Joe Spinosa
KF6CWX
Concord, CA  (CM97ax)

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