[TowerTalk] tower & antenna project questions

[F.R. Ashley]

You are quite correct.


>I am not sure, but I think if you look at the Hand Book It will state that 
>you do not want the tower or anything else to be grounded that goes through 
>concrete. The reason being that a hit from lightning
> Will cause the concrete to explode. If I am wrong someone please let me 
> know !
>
> -----Original Message-----
> From: towertalk-bounces at contesting.com 
> [mailto:towertalk-bounces at contesting.com] On Behalf Of ke2d at comcast.net
> Sent: Thursday, March 11, 2010 3:44 PM
> To: towertalk at contesting.com
> Subject: [TowerTalk] tower & antenna project questions
>
>
>
>
> Good afternoon.   Finally, the 3rd sunny day in the 50s here in NJ, and 
> time to start the antenna work!  Hopefully we'll be pouring concrete in 
> another week or two for the new tower. Nothing like having a new tower 
> delivered with 24" of snow on the ground!  Now,......
>
>
>
> I am looking to purchase a few 6m/2m/440 yagis to stack above my HF 
> antennas.  In my last installation, I used Cushcraft antennas - 13B2 for 
> 144, 719B for 440, and A506S for 6m.   The VHF/UHF will be vertically 
> polarized, as I work more FM simplex than SSB.   6M, however, will be 
> horizontal for SSB DX.   This time I am now looking at the M2 stuff, 
> namely a 2M12 for 144, a 440-18 for 440, and a 6M7 for 6m.
>
>
>
> Does anyone have any recommendations of one over the other (Cushcraft vs. 
> M2), or  recommend any other manufacturers for VHF and UHF yagis?
>
>
>
> Also, I plan to stack a Hy-Gain 7-3 along with a TH-11DX.   I was thinking 
> of placing the 40m beam above the TH11, as the TH11 has the higher 
> windloading.   Anyone have any comments on which should be on top (am I 
> correct in placing the heavier antenna lower?), and also how much distance 
> I should allow between the TH11 and 7-3 40m antenna so as to minimize any 
> potential interaction?
>
>
>
> In addition, I need to run grey conduit under ground from the base of the 
> tower to where the cables will enter my home.  I need to run 9 coax 
> cables, and a rotor control line. 10 cables total.  Each run will be 
> approx. 210ft.  100ft up the tower, then 50ft from the tower to the house, 
> then 50ft along the basement and up into the shack, then 10ft or so for 
> movement in the shack.   Due to the long runs, I was planning on going to 
> LMR600 type cable to cut down on the losses, especially at  50MHz and 
> above.   I am thinking of going with LMR600 right up to the antennas, 
> making sure to oversize the rotor loop.  I successfully used solid center 
> LMR400 for 10 years, so I might gamble this time again.  The loss figures 
> for LMR400 keep pushing me that direction! Any idea what size conduit I 
> will need if I opt to run 9 runs of LMR600 size cable and one rotor cable? 
> I was able to easily get 10 LMR400 size cables in either 2 or 2.5" conduit 
> (can't recall, as the last tower/qth was 10yrs
> ago).  I stopped at HD and looked at 3" conduit, but damn, that stuff just 
> looks too darn big, especially when it will be going into the side of my 
> home. I was planning on entering just above the concrete foundation, where 
> there is an approx. 8" sill between the concrete and where the first floor 
> rests. Same as the utilities do.
>
>
>
> One other thing - my plan was to run the conduit from the house out to the 
> base of the tower, sink a few 4x4s into the ground near the tower base, 
> then mount some sort of grey weatherproof enclosure on them. Have the 
> conduit from the house go directly into the bottom of the box, then have 
> another elbow come out the bottom, allowing the coax cables to make a drip 
> loop before they head up the tower.  Inside, I was planning to install a 
> copper plate to which I would affix 10 or so Polyphasor arrestors, and the 
> rotor control surge arrestor.  Then bond the plate and tower to common 
> ground rods near the tower.  Can anyone recommend a suitable enclosure 
> that will comfortably fit 10 or so surge arrestors, plus some room to 
> spare. I took a quick look at the DX Eng website, but their stuff only 
> accomodates two or three devices.
>
>
>
> I also need to install an electrical outlet near the base for the tower 
> motor. So I will be running a 3/4" conduit as well, from the main panel 
> out to the tower base.  Any objection to dropping the electrical conduit 
> in the same trench as the coax conduit?
>
>
>
> Finally, as far as grounding goes - is there any advantage to installing 
> three 8ft ground rods at the bottom of the tower foundation hole BEFORE I 
> pour the concrete, and run the ground wires up thru the concrete base, to 
> be attached to the tower once it is erect? Or just stick to three ground 
> rods into the dirt around the base of the tower foundation after it is 
> done?
>
>
>
> Thanks for your insight and knowledge.  I've been learning a lot just 
> reading the postings of the last month or two in preparation for this 
> project.
>
>
>
> Eric
>
> K2WD
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