[TowerTalk] Tower Work and Hints&Kinks(?)

[Dale Martin]

Excuse the bandwidth on this, but I thought it might be interesting to 
some (many?) on the reflector.

Tower work and observations

This morning, a half-dozen members of the JSC ARC met at the 
club station (W5RRR) to do some work.  I climbed the 80' tower 
which supports a 4el 15m beam at 90' and a 204BA at 80'.  The 
rotor has been giving us flukey meter readings, so the intent was 
to remove the rotor and check it out on the ground.  A second 
purpose was to try to realign the director element of the 15m 
beam.  Either a heavy wind or a heavy bird caused the director to 
rotate about 45 degrees.  It had been this way for over a year or 
two now and I was determined to fix it.  

It seemed being the easiest of the tasks to perform up there, so 
I undertook to realign the element first.  I tied a 3/4"  socket to 
50lb test fishing line.  I made a couple of test throws away from 
the antenna elements and found that if I held the spool right, the 
line would just spin off with little or no resistance.  I then threw 
the socket over the 15m beam director element such that the 
string would land out on the element segment beyond the first 
hose clamp, giving the leverage needed to move the element back 
into place.  It worked; the socket carried the line over and, still 
holding the spool with the line looping off, it went right to the 
ground.  When one of the groundcrew picked up the socket and 
string, I tossed the spool (this was 300' spool) over the 20m beam 
second director element and to the ground.  The groundcrew 
member picked that up and, gingerly pumping the line, he ever so 
slowly brought the element back into alignment with the others.  
I don't know how long it will last, but since it did not move around 
for a year or two, maybe it will stay where it is for a while...until 
the next big bird comes along. 

Earlier this week, I put a note on the reflector asking for suggestions 
regarding how to keep the mast on this tower in place while the rotor 
was removed.  One of the suggestions I received sounded so good I 
used it.  It was to take three slotted angle irons, ubolt them, one to 
each leg, and ubolt them to the mast.  I did this.  It worked perfectly.  
The mast does not move one iota.  (One thing for anyone else who
wants to try this: make sure the antennas are pointing where you 
want them to if your rotor is going to be out of service for a while. 
Also, I don't know how much torque the angle irons will take before 
they start flexing.) 

Another of my concerns was the possibility of having to crowbar and 
shim up the mast from the rotor in some way.  I guess it had been so 
long since I was last up there that I forgot what it looked like.  The 
mast end was a good 1/2" off the rotor.  I u-bolted the mast at the 
thrust bearing to make sure it did not drop and removed the rotor with 
no problems.  

I coordinated with a couple of folks in the club station to conduct a 
continuity check of the cable (might as well check that out, too, 
while I was there).  Using pin 1 lead as the common, each lead in 
turn was shorted to the common lead up on the tower.  Only the 
pin 3 lead showed significant resistance (100-180 ohms), all others 
being ~2 ohms.  We seemed to have a bad cable. 

Once I was at the tower base, and we were discussing the results, 
I noticed the rotor cable going up the tower was mated to two 
cables coming from the cable conduit (the tower is about 150 feet 
from the shack).  The interface of the three cables was with a 
connector.  The juntion was well wrapped and sealed, but while the 
tower skirts were off it was as good an opportunity to check that 
out as any.  Finally, I managed to get the sealer (I don't know what 
was used, but it was good and tough to get off) off the connector 
enough to pull it apart, I felt we had found our problem.  Water 
drained out of the connector, green stuff was around a couple of 
the pins, some of the pins were no longer restrained in place, overall 
it looked really ratty in the connector.  Since there was rain 
approaching, we taped the cables back together, put the anti-climbing 
skirts on the tower and hauled everything into the shack.   

Based on what I experienced on the tower today involving the rotor, 
I made a few mental notes to do some things that would reduce 
confusion, frustration, and potential problems while up on the tower.  

Before putting your rotor up on the tower, do a 
couple of things first: 
	1.  Make a drawing or sketch of the rotor base as you might 
be looking at it on the tower, identifying each pin by number, location 
and function.  
	2.  Place it with your rotor manual.  Make a copy of it to carry 
with you each time you go up on the tower.  
	3.  On the tower, and when connecting the rotor cable for the 
first time, make a wirelist by pin number and wire color.  Keep a copy 
with your rotor manual.
	4.  Write the pin numbers and wire colors in some kind of 
indelible felt tip pen under the rotor plate.  It may not last for years, but 
it may last until the next time you go up and find you have forgotten the connector pinout list. 
	5.  If your control cable run is a mix of different cables and, 
consequently, different colors, make a comprehensive wirelist.  
e.g.,	Rotor
	Box	cable1	cable2	rotor
	1	black	black	black
	2	white	red	red
	3	brown	orange	orange

etc.

Carry this list with you on the tower.  Any conversation  with the 
ground crew or someone in the shack will have to be in terms of 
what they are seeing there and what you are seeing on the tower. 
		
I'll be bench testing the rotor this afternoon, once I get cooled 
down and relax a bit.  I now expect it is just fine; it's the cable 
that is the bad guy in this....maybe.

Something else we tried to do with a second tower climber was 
to try to assess the problem we are experiencing with an A3S 
at 60' on a 50' freestanding tower (military, wide three legged base, 
hell to climb until you hit the smaller sections with 'normal' zig-zag 
Rohn-type crossbraces).  Unfortunately, the A3S is above the 
A3WS by about 8 or 10 feet.  The other climber could not get close 
enough to the A3S to either physically get to the boom/mast clamp 
or even visually ascertain whether there was a connection problem 
at the driven element.  

My thought is to put a couple of large pipe clamps I removed from 
the 80' tower today on the mast and use them as a single step 
about one or two feet above the thrust bearing and the A3WS.  
(The clamps once held the arm for the 40m 2el beam at the 65' 
point of the 80' tower)  This is pretty iffy, to me, but I thought I 
would throw it out here and ask what the consensus was about 
this technique.  Unfortunately, the array on the 50' tower, like the 
array on the 80' tower was installed with a crane.  So, we have to 
use our silver bullets sparingly.  

Overall, it was a good, productive morning.  The shack even got 
something of a clean-up.  A couple of members were even 
weed-whacking around the 50' tower and the old, now horizontal 
on blocks, W51 tower.  They even had a QSO with astronaut 
Mike Foale onboard Mir for a few of his astronaut buddies this 
morning.

Again, I apologize for the length of this, but I thought some of it 
might be of interest (concern?) to many on the reflector. 

73,


Dale Martin, KG5U
kg5u@hal-pc.org
http://www.hal-pc.org/~kg5u


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