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Author Topic: Tall VHF/UHF vertical on a tilt over tower  (Read 3722 times)
KD8Z
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Posts: 169




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« on: January 01, 2013, 04:59:09 PM »

I have a 50' tilt over tower and am thinking of a 17' +- vertical VHF/UHF dual band antenna like a Diamond X 510 HDM.  I was wondering if anyone has experience with these tall VHF/UHF verticals pertaining to breaking, leaking, cracking the plastic ray dome when repeatedly tilted over?   I haven't used the taller verticals on this tower and am looking for a little guidance.

thanks to all for reading my message.

73
KD8Z
D.C.
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KA4POL
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Posts: 1995




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« Reply #1 on: January 01, 2013, 10:20:05 PM »

Just a basic thought. The antenna is rated 90 mph wind load. This is definitely more than the load of its weight when tilted over, proper mounting provided. Also keep in mind tilting is just a static load, wind will cause dynamic loads, i.e. vibrations.
But may be someone with practical experience will report.
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VE3FMC
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« Reply #2 on: January 02, 2013, 07:00:58 AM »



Do you have a rotor on that tower Dale? If you do why not put a dual band yagi up there? Smaller antenna, and with the rotor it would be a far better antenna.

If not I would opt for a smaller vertical. I have a Jetstream JTB3 dual band which has worked well for me for the past three years. Only 6 feet in length and lightweight. The wind does not bother this antenna. I did have mine at 35 feet for some time and it worked well. Now it is a lot lower but I only use it for local 2 meter simplex so the lack of height is not a big issue for me.

Rick VE3FMC
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W8JX
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Posts: 5877




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« Reply #3 on: January 02, 2013, 10:09:31 AM »

Personally I would suggest a x300 instead. Not because of tilt over but rather because you want a stiffer antenna overall. This is because with antennas like the 510 when the bend over in wind it effects pattern especially on 440. With 300 you give up a few db but get a stiffer antenna that has a even higher wind rating too. A good trade off here.
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KD8Z
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Posts: 169




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« Reply #4 on: January 02, 2013, 11:36:10 AM »

Good suggestions, I have a Cubex Quad 5 band just above the tower and was thinking about an omni VHF/UHF above that or at least partially above the Quad.  I am very concerned about a limber vertical during a tilt.
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W8JX
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Posts: 5877




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« Reply #5 on: January 02, 2013, 03:01:19 PM »

I am very concerned about a limber vertical during a tilt.

Not a concern with a 300. The 200 is decent and real stiff too.
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WB2WIK
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Posts: 20601




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« Reply #6 on: January 02, 2013, 03:26:41 PM »

BTW the Diamond radome is fibreglas, not plastic.

However it's not so strong.  I've tried using these at repeater sites (towers, hilltops, windy) and every single one of them broke over a period of time.  No tilting, of course: These are fixed, permanent and very large towers.

My 2m repeater went from very strong at my home (about 25 miles away from it) to quite weak all in one day.  I figured there was a PA failure, but then drove up to the site to see the Diamond antenna had literally snapped in half, broke right at one of the locking joints that joins the sections.  I have my suspicion a large bird may have flown into it, but of course didn't see what actually happened.

This doesn't happen with Stationmasters. Wink
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W8JX
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« Reply #7 on: January 02, 2013, 04:23:47 PM »

BTW the Diamond radome is fibreglas, not plastic.

However it's not so strong.  I've tried using these at repeater sites (towers, hilltops, windy) and every single one of them broke over a period of time.  No tilting, of course: These are fixed, permanent and very large towers.

My 2m repeater went from very strong at my home (about 25 miles away from it) to quite weak all in one day.  I figured there was a PA failure, but then drove up to the site to see the Diamond antenna had literally snapped in half, broke right at one of the locking joints that joins the sections.  I have my suspicion a large bird may have flown into it, but of course didn't see what actually happened.

This doesn't happen with Stationmasters. Wink

I suspect they were the biggest ones diamond make. L F23, F718 and x510. These are not commercial duty antennas. 
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WB2WIK
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Posts: 20601




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« Reply #8 on: January 03, 2013, 09:30:00 AM »

BTW the Diamond radome is fibreglas, not plastic.

However it's not so strong.  I've tried using these at repeater sites (towers, hilltops, windy) and every single one of them broke over a period of time.  No tilting, of course: These are fixed, permanent and very large towers.

My 2m repeater went from very strong at my home (about 25 miles away from it) to quite weak all in one day.  I figured there was a PA failure, but then drove up to the site to see the Diamond antenna had literally snapped in half, broke right at one of the locking joints that joins the sections.  I have my suspicion a large bird may have flown into it, but of course didn't see what actually happened.

This doesn't happen with Stationmasters. Wink

I suspect they were the biggest ones diamond make. L F23, F718 and x510. These are not commercial duty antennas. 

Yeah, they're not.  But if I were installing an omni atop a tall tower at any location and wanted it to stay up there without service for years at a time, I'd invest in a commercial duty antenna -- even a surplus one, to get a better cost point.

I've had tilt-over towers before and after tilting them once or twice I hoped I'd never have to do it again. Wink
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KD8Z
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Posts: 169




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« Reply #9 on: January 03, 2013, 07:06:40 PM »

My tilt over telescoping tower is made by Aluma Tower.  Aluma tower makes a lot of equipment for the military.  Also, an Aluma tower is very easy to tilt/telescope.  They are made of all aluminum and are very light, easy to raise, lower, ETC.  BTW, Aluma tower has the greatest follow up warranty and just plain great customer service, when my winch went South they replaced it at no cost without argument, even though any warranty was well past.

73
KD8Z
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