[TowerTalk] Tower in the woods?

[Randy Farmer]

Thanks for the advice, Jim. Since I no longer climb (neither the XYL or 
I want me to now and most likely won't be able to later) I really want 
to go with a tower that allows me to maintain the antennas and rotator 
from ground level. Unfortunately, that means a huge lump of concrete at 
the base with a surrounding cleared space to lay it over on a tilt 
plate. I'm undoubtedly looking at a situation that calls for some sort 
of road to be bulldozed through the woods to reach the tower site.

I haven't yet come to grips with what I'll do for 160 and 80 meters yet. 
It will probably be heavily influenced by where and how tall the tower 
or towers turn out to be. I'm not sure just what critters we have in the 
woods around here, but I know there are lots of deer. We're probably 
down in the foothills of the Blue Ridge far enough that bears shouldn't 
be a problem. I'm planning to install a BevFlex -4X receive antenna soon 
and I plan to run it at least head high anchored to trees. We'll see if 
that survives the local wildlife traffic.

73...
Randy, W8FN

On 8/18/2020 6:40 PM, Jim Brown wrote:
> Hi Randy,
>
> Several thoughts, based on my experience in a dense redwood forest. 
> These are very substantial trees, so all my guy-points are lagged into 
> the base of a different tree. It's 120 ft of Rohn 25, so that's 12 guy 
> points (30, 60, 90, 120 ft) and at the right vertical angle for each.
>
> It took me a couple of years (and help from K7LXC) to find a place 
> where I could turn a 3-el straight SteppIR. Even at that, a couple of 
> dead ones had to come down, and upper branches around the antenna need 
> to get trimmed every few years.
>
> The only reason for burying radials is to physically protect them or 
> prevent fall hazards for people or animals. We have no people, but do 
> have deer, coyotes, mountain lions, and assorted varmints. I have both 
> on-ground and elevated radials on three different 160M verticals.
>
> In general, vertically polarized antennas don't work well in dense 
> forests. Horizontal antennas are less attenuated. 160 is the only band 
> where they are better than horizontal antennas. I've tried good tall 
> verticals on both 40 and 80, without success. The reason the verticals 
> are better on 160M is that any horizontal antenna for this band that 
> mere mortals can rig are very low as a fraction of a wavelength.
>
> The bases for both of my towers were mixed in a relatively small 
> portable mixer at the side of the hole. No way a truck could have 
> poured either of them. Took a LOT of help from friends. Both towers 
> have bases over-sized for mfr recommendations. All my RF and control 
> lines are laying on the ground. All the TX coax is hard line, mostly 
> 7/8-in. RX antennas are flooded Commscope RG6 like DX Eng sells. The 
> only failure in 12 years was the control line for my SteppIR, and that 
> occurred at a point where I'd had to re-route it under a newly built 
> deck where rabbits had moved in.
>
> Experience with varmints varies with location, but before going nuts 
> with trenching, I'd tightly bundle everything, using more robust lines 
> like hard line to make control lines harder to munch. This assumes, of 
> course, that you don't need to trench to get under human traffic, 
> driveways, etc.
>
> Rotator cable is a pair of 14-3 romex to the base of the more distant 
> tower, with something smaller going up the tower. Wire gauge was 
> chosen by translating the mfr recommendations using Ohm's Law.
>
> I have no AC at either tower. All control lines are spliced at the 
> base of the tower, RF runs are continuous from just outside the shack 
> to the rotator loop. Short jumpers of RG8 tie them to the grounding 
> panel.
>
> Hope this helps.
>
> 73, Jim K9YC