Coax Junction Box at the Base of the Tower
Images Copyright Roger Halstead 2003
The bundle of cables comes out from the basement and shop in buried conduit to the tower.
| The concept is fairly simple... I needed to get nine runs
of coax from the top of the tower to the basement and now it's also to the shop.
Nine runs laying on the ground wasn't a very good idea and it would also be difficult to get
them into the basement...or shop
So, I went with 4 inch plastic electrical conduit. NOTE, I used two "Sweep 45s" for the 90 degree turn from the underground line to the box
inlet.
The only reason the conduit goes into the right side of the box is due to the way the conduit lengths worked out. That and I didn't have enough
fittings to cut the thing off and redo it.
Installing, or "pulling the coax (LMR400) plus several RG-6 for the TV antennas and one dual run of control cables and two RG-6 as a unit for the
C-Band satellite dish was not all that difficult using "wire soap" which aids sliding the cables through the conduit.
The cables were bundled together and then pulled through using a standard "fish tape" NOTE that I am no longer using the 3/4 inch hardline.
As I recall the "box" is a standard Hoffman cabinet 14 X 16 inches and 6 inches deep.
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The interior of the cabinet shows the cables just come up
from the underground conduit and loop out through a conduit stub on the
left. The stub is to keep rain and snow from getting into the box.
This stub has been replaced with a conduit from the shop and the cables now leave the box via bulkhead connectors,
or compression feed throughs yo keep nature and critters ouy.
What appears to be a bundle of smaller cables that go over the other
cables is actually a single cable containing the control wires and the
equivalent of two RG-6 coax cables to the C-band satellite dish.
The C-band dish and cables are now gone.
The sealant was to keep bees and "varmints" from getting into box and then into the house through the conduit, or nesting in the box.
Prior to sealing I took out two Yellow Jacket nests.
The cables coming down the tower and into the box need to be rerouted
for both safety and neatness. All cables go through lightning
arrestors higher up the tower and the shields will be grounded to the tower
prior to entering the box. NOTE the yellow band on the one coax. All cables are color coded.
Each feed line now has its jacket grounded using bulkhead connectors at the top and bottom of the tower. The
Lightning arrestors are now on the grounding bulkhead where the coax enters the house.
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NEMA enclosure mounted over the end plate between the floor
joists. This replaces the old conduit that entered through the
basement wall. This will eventually be replaced with a box
about twice the size of this one. Incidentally, when we had work done on our drain field, they hooked the ground cable
and managed to pull out a section of basement wall. |
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The grounded panel inside the NEMA enclosure. Note the "PolyPhaser" lightning arrestor
in the bulkhead and the 3" conduit going into the basement through
the end plate. Only one PolyPhaser is installed in this photo, but they will be in each line.
Also note the RG-6 cables for the satellite system going through
grounded bulkhead connectors. Eventually there will be grounded
bulkhead connectors in each coax line at the base and top of the
tower.
The white "rope" is a messenger cable used to pull a heavier
messenger cable through the conduit to pull in any additional cables.
(Uses lots of the yellow "wire soap" |
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Just as an added note for those who might be interested, this is the
conduit (before it was rerouted through the end plate) fully exposed when we redid the basement walls and weep tile.
Note the two heavy ground wires running along with the conduit. There
are several ground rods that do not show in the photo. The
ground cables tie the ground systems for the station in the house and
the towers together with a total of 33, 8' ground rods CadWelded (TM)
to the cable. BTW it was 90F plus while they were spraying the
walls with that asphalt. |
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October 2008: Besides the stock market needing some help, so does my
antenna system. BTW it's certainly not in the 90's at present!
Last time up the tower I cut the ends off the pigtails (rotator loops) going to the tribander, 7L, 6-meter C3i Yagi, as well
as the 144 and 440 arrays. I then brought down all runs of the LMR 400 except the one to the Diamond 144/440 side
mounted vertical. All of that coax is still in good shape. Too bad the pig tails of LMR-400UF weren't. The jacket had
split on all but one of the pigtails, rendering it just a matter of time before any or all of them fail. I had planned on
replacing the LMR-400 with LMR-600UF, but after seeing the state of the Ultra flex (UF) jacket I have decided to go with the much
more rugged Davis BuryFlex cable. The coax running through the conduit to the house entrance also has to be changed out to
LMR 600. It works out all of the pigtails except the one to the tribander are 28' long. Whether I remove and repair
the 144 and 440 arrays is still under question. I may just put a single Diamond 144/440 repeater antenna up there for
JNOS, but I'm afraid it'd be gone after the first thunderstorm. I say that particularly with the knowledge as to how many direct
lightning strikes the tower has already taken.
KD8MRC came over and between me handling the ropes and him doing all the work we did get all the antennas down
A couple of issues remain: Those pigtails? I decided the good stuff would make good jumpers in the station.
As I was installing the connectors on the second jumper, I discovered the braid and shield had a lot of white powder on them
That meant water contamination even though the jacket looked good, or at least usable. The jacket had turned dull from UV exposure.
It looked good with no holes, splits or cracks, but apparently it was porous. Sooo...the whole 140 feet went in the trash and I used the LMR-600UF
in the conduit where it's protected and easy to ge at.
I only had the top section left to do on the 25-G when
Nature surprised me with a heart attac. So my climbing...and flying are pretty
well done. Looks like hiring a climber and having a couple of antenna/tower
parties this spring. NOW I wish I'd settled for a couple of crankups even if
they were a bit shorter.
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| Old 14 X 16 Box |
Replaced with New 20 X 24 Box |
As I have a small back up station in my shop (Not so small any
more ) I have decided to set the entire
station up as SO2R or in plain language, Single Operator 2 Radios. That
means replacing the 14" X 16" box at the bottom of the tower with a new 20" X
24" NEMA 4 enclosure. This box mounts to the tower legs using 1 1/4" SS
saddle clamps through 19" X 4" X 1/8" steel adapter plates, top and
bottom. This makes for a very solid mount. OTOH it also made alignment of
the existing conduit more difficult. I added a second 3" PVC conduit run
that will go to the shop. This required an 18" deep trench about 10" wide from
the tower base to the South side of the shop where a 10" X 10" X 6" NEMA 3 box
is mounted. That box connects to a similar box in the inside of the wall through
two, 7" long pieces of 2" rigid conduit which makes for a very rigid
mount.
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The trench for the tower to the shop. Notice the
conduit
45 coming out of the north side of the box on the tower |
Box on the South side of the shop. Notice trim around
box to match siding
Conduit needs to be about 6 to 8" deeper on that end. |
(Status as of Oct 15) I had planned on trimming the siding away from the NEMA
3 box, adding the trim, and installing the second 7" piece of 2" conduit. That
would give a neat and rigid installation. Unfortunately about the time I
pulled the box away from the wall I felt something hit my neck. It was
starting to sprinkle. I had just enough time to get the box back in place
before it started raining.
All coax has been pulled from the conduit to the house except for the RG-6
for the TV. Bulk head connectors have been installed in the 20 X 24 box
allowing the satellite and TV antennas to be reconnected. The LMR 400 to
the side mounted 144/440 Diamond vertical has been temporarily rerouted to the
shop. The coax to the sloping dipoles is routed into the shop, but still
laying on the ground.
Once the conduit is installed I have what is called a 6-pack that will be
mounted inside the 20 X 24 enclosure. One coax from the HF/6-meter station in
the house and in the shop will run to this box. I'll then be able to
select any antenna from either location. There will be two
additional remote antenna switches mounted about 15 to 20 feet up the tower with
one serving for the 75 meter band and one for the 40 meter band.
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| Conduit is in place |
Trench is filled |
(10/17/08) I now have the conduit hooked up at each end, the trench filled (with the
exception of the sod), but no cables in place yet.) NOTE: There are no
large openings to the outside world in this installation.
(10/18/08)Sod is back in place, cables pulled in from shop except rotator
cable. Two runs LMR-600, 3 control cables, and one RG-6. Now to hook up
the two remote antenna switches, the 144/440 side mounted vertical, the 6-pack,
and add connectors to LMR-600 in the shop.
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| The view between the shop and tower. |
Note "Wire Soap" on cables.
2 X LMR-600, 3 control cables, & 1 RG-6 |
11/02/08: 6-pack is in equipment box at base of tower. Two runs of
LMR-600 plus control cable pulled in from tower to house. One remote antenna
switch is temporarily mounted at about 3' above the top of the equipment box. 75
meter sloper to NE and the 40 meter slopers to the NW and SW are hooked to remote switch.
Switch is now operable from the station in the shop. Heard an ON4 over S-9 on
3.775, but unfortunately he didn't hear me. I still need to add one more
run of LMR-600 and two control cables to the house as well as one more LMR-600
and a rotator control cable to the shop. Of course there is the need for an
underground conduit between the shop and garage for the network and telephone
cables. One step at a time.
Hopefully I will be able to remotely control one or both stations via
computer and the Internet.... Eventually!
Unfortunately all of this work has delayed the removal and repair of the
whole system at the top of the tower. Looks like I'm going to be wearing
some heavy clothes for that work. Seems like just yesterday it was to hot
to work in the middle of the day.
The 
says you are caller
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