[TowerTalk] Antenna Heights

[Roger (K8RI) on TT]

Theoretically the crank-up would work for finding the "best height", but 
I'd think this is where the advantage for stacked, switchable arrays, 
with diversity reception would excel. (for the few who can afford them 
and have the real estate large enough with zoning that would allow 
them.)  IIRC The QST article also dealt with optimum height for the 
distances desired.

The crank-up disadvantage would be the speed of change (slow) and method 
of knowing when you really hit optimum, or a minor lobe. Sometimes, you 
might be hard pressed to keep up.  Finding a peak might involve many 
reversals and short travels.

For those of us on pensions augmented with SS a used crank up and the 
ability to change the cable often would represent the "poor man's 
approach"  for best height, but it would put the tower under much more 
use than the designer's had expected.  Replacing cables (buy in bulk and 
make your own) most likely at least once a year, or more.

What else would be exposed to excessive wear and what kind of 
maintenance would be required?

I don't know if it'd be an improvement or not, but I'd prefer a heavy 
duty, industrial chain drive instead of a V-belt.

What about the coax and control cables?  They would see much more 
movement and would need a trust worthy monitoring system as you aren't 
going to be able to watch other than by remote TV while suffering many 
distractions "at hand" .  So I'd expect to be replacing coax and control 
cables/wiring much more often.

I always did my own maintenance, but physically that is no longer 
possible. From appearances at swaps and conventions, I'd guess there are 
many hams who are physically incapable of doing more than minor 
maintenance.  On here I have gained the impression there are many 
"listeners/readers" who are not mechanically inclined enough, or possess 
the knowledge to do much of this type of work, safely.

Ham radio has many fields within the service and I'd not expect every 
one to be capable of servicing their gear.  Rigs have become extremely 
complicated and some antenna systems very complex.  My knowledge has not 
been able to keep up with the technology used in many of today's rigs.

Working on towers is dangerous. The results of improper maintenance, 
particularly on crank up towers can be very dangerous. Even lethal!  
Building large towers and installing heavy duty crank-up towers may 
require an engineering analysis of the soil.  I can judge soil's 
ability, but I do not have the background to do a soil analysis, let 
alone and official one the insurance company would take.

So all in all, I'd expect the use of a crank up to try and find the best 
angle, or even an improved angle to come with considerable hidden costs 
including labor.

In the end, I'd put the antenna but only a bit higher than "optimum".  
It'd still work and probably well , just not optimum which for me is 
good enough.

73

Roger (K8RI)

On 4/16/2015 11:09 AM, Gene Smar wrote:
> TT:
>   
>       Might telescoping/crankup towers provide the best of all worlds, then?
>   
>   
> 73 de
> Gene Smar  AD3F
>   
>
>
>
> On 04/16/15, Roger (K8RI) on TT wrote:
>
> Remember, that when we talk of "best heights" that is a statistical
> number and is not always the best height. I don't have the numbers in
> front of me, but there was a good article in QST I believe last year.
>
> Say, the best height is 60 feet 30% of the time, the other 70 % is
> spread through a variety of heights. So, when going for the best height
> it just means that height will be better than the others more often.
> Higher might give stronger signals, but fewer times. "Best Height" is
> dependent on frequencies, band conditions, and local soil conditions.
>
>


-- 

73

Roger (K8RI)


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