Some of these have been answered and some scare me.
Read the Polyphaser pages.
http://mobileers.com/main/getting-on-160/grounding-information/grounding-notes-by-polyphaser/
is a good place to start, but they have many pages.
I have the junction box mounted on the tower. (
http://www.rogerhalstead.com/ham_files/cablebox.htm ) A 45G in my
case. I use two sweep 45s in the conduit to reach over the concrete.
Copper strap is best, but I used bare #2 copper cable as it was
available locally.
The ground does not run in the conduit, but along side of it from the
entrance panel, to the tower grounding system. One 8 or 10' ground rod
at least 3' from the concrete for each tower leg (I believe 6' is
better, but someone on here should have the proper distance. Use the
info on the Polyphaser site). I have the 3 ground rods as the
beginnings of a grounding run extending out about 75 to80 feet with
ground rods every 16 feet. I believe common wisdom is to NOT ground the
guy lines. I use non conductive guys (Phillystran) so that is not an
issue.
Use the ROHN pages for tower ratings. 25G without guys is about 30 feet
with a very small antenna. I would not put up a 25G without guys.
73
Roger (K8RI)
On 4/25/2016 Monday 5:42 PM, Rob Matherly wrote:
Hi All -
First time poster to the list, long-time lurker.
I'm getting set to install my first tower after having been in the hobby
for nearly 20 years. I'm going to install 40' of Rohn25 with a Hazer. I'm
going to set it in a 4x4x5 block of concrete that I have the option to make
it taller later on (without the Hazer, of course.)
Please advise if I am correct: I do not need to guy the tower given the
base size and height, correct? I've been told I can go up to 50' unguyed
by some, but others say anything over 40' needs guyed.
Regarding grounding: I've seen different ways of doing it. What is the
best way to ground the tower? Rod at the bottom of the hole? Rod to the
side of the slab?
I'm going to feed it underground with a 3" CPVC line coming up into a
weatherproof box mounted a short distance from the tower. Do I need to tie
the ground bus in the cabinet to the ground in the tower, or do I need to
keep them separate?
Thanks
Rob
w0jrm
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73
Roger (K8RI)
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