Many thanks for all the suggestions (and photos). I am checking with the
person who dug the hole for the current base (for the 40' aluminum tower).
If it is at least 5' deep, I will probably reuse the current base by making
a steel plate that is welded to the current base legs in the concrete and
has matching bolts for the TX-455 base. (The base legs (embedded in
concrete) of the aluminum tower are steel.) Some thought is needed about
how to attach the new base bolts to the adapter plate.
If the current base is too shallow, then I will probably pour a new base
--- perhaps right next to the existing base. The existing hole was dug
with some care and the earth around it (and under it) was undisturbed.
- Keep the 40' tower and put up another 70+' tower: (Would be nice,
but not in my location.) I have no legal restrictions, but I do not want
to stand out too much in the neighborhood.
- Hire a tower climber: It is difficult to explain what needs to be
checked on an antenna or coax switch or rotor, etc, etc. Also, I tend to
experiment with wire antennas and I do not want to try to explain all this
to a hired climber.
- Install a pole to easily tilt the current 40' tower: I never
thought of this one and this could be a fall-back plan if everything else
- Go for a taller tower, or go for the HDX-455 (heavy duty model): I
am not attempting to be a DX top gun and the 55' seems to be a reasonable
balance between performance and peace with the neighbors. If the quad goes
away, I would probably replace it with a 10 element LPA. The TX-455 seems
reasonable (from the published specifications) for either of these. My
location is slightly protected and I would crank it down if severe weather
My location is a little "down" from the nearby areas to the north --- which
is where the quad is usually pointed. I assume an extra 15' (the crankup
would be 55' vs my current 40') would help a little. Also, with the 55'
tower, I could better hang some wire antennas off of it --- or use it for a
half-sloper. The 40' is a little short for this because I do not want to
get any wire antennas too close to the quad. (I really like the quad!)
Again, thank you for all the suggestions and comments. (Anyone interested
buying a 40' aluminum tower in excellent condition? Should be available in
a few months. Will deliver anywhere in mid-New York, assuming the sections
of the tower come apart without much trouble.)