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Author Topic: DB224e Antenna  (Read 13228 times)
K6ECS
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« Reply #15 on: March 08, 2014, 07:20:18 PM »

We are top mounting the DB224e atop an 80 foot tower. The winds are usually no more than 40mph with occasional justs. All elements will be mounted 90° apart unless I can get a Station Master ASAP.

I also need some parts. What is the name of the Canadian company that sells refurbished parts? RF.....
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W8JI
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« Reply #16 on: March 09, 2014, 05:54:29 AM »

We are top mounting the DB224e atop an 80 foot tower. The winds are usually no more than 40mph with occasional justs. All elements will be mounted 90° apart unless I can get a Station Master ASAP.

I also need some parts. What is the name of the Canadian company that sells refurbished parts? RF.....

I would not top mount a DB224, but that's just me. I don't believe the antenna base area or tower will handle it well, if it is a small tower. I especially would not top mount using universal clamps. The stress would be far too high for those clamps unless spread over three or four feet.

The antenna is fine, but the leverage on the mounting point is a killer.
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K6ECS
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« Reply #17 on: March 09, 2014, 09:37:41 PM »

The antenna uses the standard DB365 mounting hardware. The bottom clamp attaches 8" from the bottom and the top clamp mounts 12" above that. Users here and a call to CommScope indicate that the antenna can be mounted vertically. The tower is definitely not small and now has a Verizon triangle below the top. We will mount above the top of Verizon.

I'm still not sold on the idea either Smiley
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K6ECS
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« Reply #18 on: March 11, 2014, 10:28:06 AM »

I'm sorry that I didn't hear back from you. With that said, If I mount the antenna brackets 12" part as indicated but also mount a third bracket at the bottom shouldn't that adequately secure the DB224e to the tower?
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W9GB
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« Reply #19 on: March 11, 2014, 06:10:46 PM »

Quote
The tower is definitely not small and now has a Verizon triangle below the top. We will mount above the top of Verizon.
I assume the 6 mounting stubs on the Verizon cellular triangle are occupied or "off-limits" ?

Top of the Castle Hayne, NC antenna tower sounds like your situation.
Scroll down for photo.
http://www.carolina440.net/RepeaterTechnicalInfo.htm
« Last Edit: March 11, 2014, 06:15:36 PM by W9GB » Logged
W8JI
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« Reply #20 on: March 12, 2014, 05:01:31 PM »

I'm sorry that I didn't hear back from you. With that said, If I mount the antenna brackets 12" part as indicated but also mount a third bracket at the bottom shouldn't that adequately secure the DB224e to the tower?

We had a lot of antennas like that around Lake Erie, and the the worse issue was always with the clamps rotating on the antenna and tower. The standard universal clamps were just not resistant to spinning with that big 20 foot plus lever bouncing on them. The result is a leaning antenna.

The antenna itself is pretty strong. If you use a couple plate clamp systems spread out, using saddle clamps that fit the tower and antenna snugly in a full gripping circle, it will be OK. Those "Motorola" style clamps just out pressure on four sharp points where the V's touch the round members. 
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K6ECS
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« Reply #21 on: March 12, 2014, 09:18:34 PM »

Why not drill a hole through the bottom clamp and put a pinning bolt in? If it is below the standard mounting brackets I don't see it weakening the mast and it won't rotate.

But I don't understand "lever" and "leaning." What am I missing here?
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W8JI
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« Reply #22 on: March 18, 2014, 03:31:51 AM »

Why not drill a hole through the bottom clamp and put a pinning bolt in? If it is below the standard mounting brackets I don't see it weakening the mast and it won't rotate.

But I don't understand "lever" and "leaning." What am I missing here?

Look around at commercial antennas that are bottom mounted with clamps to legs. Many of them get the "gangster lean" instead of standing vertical.

This is because each normal universal clamp only puts pressure on four points of the tower leg and four points of the antenna, instead of fully round compression. The leverage of the long antenna working on the clamp causes the clamps to slip and rotate.

If you understand bolts and fasteners and how they stay tight, the universal clamp it is a terrible system for resisting rotational forces caused by that long lever when the wind is in line with the clamp brackets (at right angles to the bolts).
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