Tower #2 Rohn BX-48:
Tower #2 will be primarily FM
use, with small beams for each band, a dual band vertical on top, and maybe a
few other small things later on. It will not be the larger
install as tower #1 takes care of all the SSB operations quite nicely. As
this tower will be slightly taller and the top of the mast will actually clear
the top of the trees on my property wind and ice load will be more of a concern,
I'm going to keep its antenna load light. Tower #1 is actually quite
sheltered and doesn't suffer much from wind
and other conditions.
Yaesu G-800SA Rotor
Cushcraft 124WB
Cushcraft A449-6S
Jetstream JTB2 Dual Band 6/8db
DX Engineering Utility Enclosure
Jetstream JT40R
Lightning Arrestors (Coax Feed Protection)
ICE Radio Products Transient
Suppressor / RF Filter (Rotor Cable and Remote Coax Switch Cable Protection)
Homebrew Coax Switch, Look on the Hints & Tips page
for its construction!
Maxrad MFB-8585 5db 806-866 Mhz
Polyphaser
IS-50NX-C2
Andrew FSJ4-50B 1/2" Heliax
Tower #2 is a used Rohn BX-48, though it was originally a BX-56. Section number seven was chopped off at the bottom, rather than rework it I decided to use section number seven as the concrete base instead of purchasing base stubs. Digging of the hole by hand, took a few days, and I even got a little help this time! Thanks to Dan ABØRE for his help in completing the last foot and a half, it wasn't easy digging this time either!
Before installation could start a large Maple tree which was in need of removal anyway had to come down, it took a few hours for a tree removal service using a bucket truck to remove this tree. The stump measures roughly 46 inches across!
Formed up about like last time.
And here it is, cured enough to clean everything up and get rid of the forms. Along with the other tower in the background. You can see there is a couple feet of the section seven above the level of the concrete, this should make it roughly 50ft tall once the tower is complete.
I also needed to install conduit underground from the house to the tower to carry all necessary cables. Here is the exit/entry to the backside of the house. It still needs some sealant around it where it meets the house, on the to-do list for a day without rain.
Conduit trenched in to the tower base.
Conduit exiting the ground at the tower base.
As of today, 9/13/08, everything but the top section is up in the air. Thanks to Rob NØTAW for braving a cold bug and a rainy/gloomy day. Just as he started to bolt the last section in place a clap of thunder was heard in the distance and it began to rain shortly after! What timing!!
Finishing the assembly of the cross boom and Yagi's. (Yep, that's me)
The top section going up!
And up! And there we have it.. Whew...
(Hmm, should I toss it back down?) And here it is bolted into
place!
Now it's time for the mast to go
up with the antenna's on it! We removed the thrust bearing from the tower
after the mast was aligned and centered into it, making for a four bolt install
on the top of the tower rather then trying to install and center it while off
the ground. Looks pretty cool hauling it up doesn't it?
Almost there, just a little
more!
And here it is, after I started
breathing again.. What you didn't get to see is him trying to spear it
into the hole on the top of the tower, made me worry a little bit as it was a
bit awkward looking!
And here it is, a little more tightening
and tweaking and that's all for today! Many THANKS to Rob NØTAW, tower man
extraordinaire.. (AKA Let-R-Lean Tower Services, Inc.)
Today I started with the rest of the
ground work to get this tower operational. First thing to do was get the
ground panel mounted and get the coax and rotor cable snaked out through the
conduit in the ground to the base of the tower. The blue rope exiting the
conduit with the cables was pulled through at the same time so I can pull
additional cables at a later date as needed. Getting the first few through
is not bad, but trying to snake additional cables when something else is already
in the way can be a major pain, best to leave a pull line for later!
Cables run into the grounding panel, to
the left is the ICE rotor/control line surge arrestor. To the right is a
Jetstream JT40R coaxial arrestor. All the cables are just wrapped up in
here for now, waiting on some connectors to finish it up. The tape on the
top right corner of the box is covering the hole where the cable grommet goes,
that's removed until I have the jumper cable from the arrestor to the coax
switch made.
Cables from the top dual band vertical
and the Yagi's run to the coax switch mounted to the tower.
The connections all made in the
grounding panel.
One last look from the street showing
both towers.
The next addition to this tower is in
progress. I just completed the installation of a Polyphaser arrestor and
Andrew 1/2" Heliax to the grounding panel on the tower. This will be for a
800Mhz vertical for the scanners. I wanted to make sure I had as little
loss as possible while still being affordable. So I got some 40ft lengths
of Heliax and some surplus but brand new N Connectors. Along with a new
surplus Polyphaser arrestor I have the feedline taken care of.
The antenna planned for this install is
a Maxrad MFB-8585, its a 806-866Mhz 5dB gain antenna factory tuned for a center
of 858Mhz. Perfect for monitoring the new statewide radio system being
implemented here in MN. The ARMER system is slowly but surely approaching
my area, and some neighboring counties are getting converted to the new system.
This antenna was purchased used from eBay, and was in far worse cosmetic shape
then it is now. It had remnants of red and white tower paint on it, and
was also UV faded. It was wet sanded, repainted, and again wet sanded and
polished to give it a nice fresh white appearance. Tested and ready to go
after installing a new N connector on its coaxial pigtail and modifying some old
Diamond antenna clamps for mounting.
Inside I used a Comet CF-4130B diplexer.
The low side is VHF/UHF, and the high side is 800-1400Mhz. This will allow
me to use my current dual band antenna, the Jetstream JTB3 on
Tower #1, for VHF/UHF to the scanners and the new
Maxrad 800Mhz on Tower #2 for the scanners at the same time. I slightly
modified this diplexer, I disassembled it and removed the stock Male connectors
for the high/low ports and installed Female panel mount connectors in their
place. Took a little time to modify and machine the case to accept them
but in the end was worth it to make everything standard and not having to
install inline females on the feed lines.
Coax Patch Panel.. From this point i can
connect any radio to any antenna or remote coax switch located on either of the
two towers. Its still in construction right now, needs a ground run to it,
also the control cables have only tied up out of the way, they will be better
organized and relabeled. The coax runs are color coded with heatshrink
tubing.
With a break in the weather today we
installed the antenna! Sorry for the picture quality they were taken
quickly with my phone. I will get a finished install picture of better
quality up soon. That's Rob NØTAW up on the tower doing what he does best,
tower work!
That's all for now! I might make
some additions to Tower #2 in the future, and if I do they will be shown here.
This site was last updated 05/24/13