OK, I'm in my final (I hope) figuring for my antenna/tower installation. I'm considering mounting the tower on my deck which is made from 2" x 6" decking with 2" x 8" rafters on 24" centers. The deck is sitting on 6"x6" posts and is VERY WELL supported. There are 7 of the 6"x6" posts supporting the 20' x 20' deck. The deck is only about 4 years old and is VERY sturdy.
The tower will be Rohn 45G and the gable of my house is 13' above the top of the deck. I am going to use a house bracket near the top of the first section at approximately the 9' level and one or two sections on top of that. Probably one section will be enough and will put the top of the tower about 7' above my metal roof which is well over 1/4 wavelength on even on 6M.
I haven't figured out what mast and thrust bearing I am going to use yet. I will be using a Yaesu G-5500 rotor in a split configuration with the AZ rotor inside the tower and the EL rotor above the 6M beam and a fiberglass cross boom for mounting the satellite antenna's.
I want to install a homebrew 3-4 element 6M beam directly above the tower and above that an M2 2MCP22 and M2 432MCP42 with ARR preamps for both. That will be all of the antenna's on the tower so the loading should be rather light. I am also intending to install another 6"x6" post directly under the tower for added support.
Now, before anyone asks why I'm wanting to install on top of the deck I will explain. The deck is about 8' off the ground on the above mentioned 6"x6" posts and I don't see the need to install through the deck and into my pavement driveway just for 2 sections of tower. Especially since it will be mounted with a house bracket near the top of the first section and only one section extending above that. Does this sound feasible or am I gambling?
Any suggestions or recommendations? Positive or negative. All are welcome...All are welcome :-0
Thanks, RoD KD0XX
A good friend will come and bail you out of jail, A TRUE friend will be sitting next to you saying.....
"DAMN THAT WAS FUN"
Rod,
Sounds good. Rohn-45 really much more tower than needed for the antennas you are considering. I am using a 50-foot Rohn-25 to support two 6m beams, HF Tribander, 222 and 432 antennas. My tower is also uses a house bracket (HB from angle-iron) at about 12-feet (but this is from ground where I use a hinge-over plate in concrete slab (12-inches deep). At 45-feet I do have guys, but you need not use them on your shorter tower. I see no problem attaching the tower to your deck if you use large bolts backed with metal plates. I suppose you will use a std tower base plate or the hinge-over plate.
On item caught my attention: the height above your roof (7-feet). If you check the length of the 436CP42 and 2MCP22, both are about 18-feet long. When elevated to 90-degrees (straight up) they will need a min of 9-foot clearance (best make it 10) to your roof. You can extend using a mast to the elevation rotator above the tower top. I plan to use a single Rohn-25 ten-foot tower top to support my satellite antennas using the B5400 az-el rotator mounted about 5-feet above the tower. I have the 436CP42 and a KLM-22C (predecessor to the M2CP22), plus a 33-inch dish for 2400. Sounds like your setup will be quite similar.
I using the hinge-over plate so I can layover the complete tower for antenna maintenance. One section is easily raised by hand by two people. You might secure a pulley to the house and raise the complete tower buy a cable and hinge-over base. 20-foot tower + 5-foot mast would likely require using a car or ATV to pull the cable (but a good work party of 4-hams might do it with a stout rope).
I have the Rohn bronze mast bearing for 1-1/4 inch mast (it is not needed as I went with the Rohn bearing plate and thrust bearing on my 50-foot tower) if that would work for you? Might not fit Rohn-45.
Ed - KL7UW
At 04:43 PM 5/13/2007, Stargate wrote:
OK, I'm in my final (I hope) figuring for my antenna/towerinstallation. I'm considering mounting the tower on my deck which is made from 2" x 6" decking with 2" x 8" rafters on 24" centers. The deck is sitting on 6"x6" posts and is VERY WELL supported. There are 7 of the 6"x6" posts supporting the 20' x 20' deck. The deck is only about 4 years old and is VERY sturdy.
The tower will be Rohn 45G and the gable of my house is 13'above the top of the deck. I am going to use a house bracket near the top of the first section at approximately the 9' level and one or two sections on top of that. Probably one section will be enough and will put the top of the tower about 7' above my metal roof which is well over 1/4 wavelength on even on 6M. --------snip
73, Ed - KL7UW ====================================== BP40IQ 50-MHz - 10-GHz www.kl7uw.com 144-EME: FT-847, mgf-1801, 4x-xpol-20, 185w DUBUS Magazine USA Rep dubususa@hotmail.com ======================================
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Stargate