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Antenna mast to guy or not to guy


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#1 ljones135

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Posted 01 March 2020 - 07:15 PM

Getting ready to put up a base station antenna using fence top rail. The mast will be 2 10' sections stacked onto a 2' section mounted to the house. The antenna I'm going to use is the DPD GMRS Verticle Outdoor Base Antenna. It weighs a whopping 1lb. Should I use guy wires or not. Should I use a different material for the mast? Suggestions please. Thanks

 

 

 

Larry @ WRAK 287



#2 JohnE

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Posted 01 March 2020 - 08:31 PM

guy at it at the top and half way down


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#3 marcspaz

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Posted 02 March 2020 - 01:08 AM

guy at it at the top and half way down

 

 

Agreed.  Mine is fiberglass and is guyed with some UV and weather resistant paracord to help reduce lightning risk.


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#4 scottmckinney67

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Posted 22 March 2020 - 06:12 PM

I'd probably do one 10 foot section and call it a day.  If you don't get the range you want, guy and another section of top rail.  Good thing about top rail is you can just pop in another when you want with no hassle.



#5 VeritasVosLiberabit

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Posted 19 April 2020 - 01:18 AM

Agreed.  Mine is fiberglass and is guyed with some UV and weather resistant paracord to help reduce lightning risk.

 

Marc, what part of the antenna is fiberglass and why does paracord reduce lightning risk? I thought antennas must be metal?



#6 marcspaz

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Posted 19 April 2020 - 08:41 AM

Marc, what part of the antenna is fiberglass and why does paracord reduce lightning risk? I thought antennas must be metal?


The entire mast is made out of fiberglass. The antenna is a small metal wire inside of a 10 foot fiberglass pole, too.

Lightning looks for the path of least resistance. Compared to a nearby tree or a metal mast and wire guys, my antenna system is more isolated from ground. Therefore less likely to take a direct hit.

#7 RickW

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Posted 19 April 2020 - 12:58 PM

Perhaps this is a bit off subject, but over the years I tried various ways of getting some height with various home made supports. I wanted something that I could handle by myself. One of my current supports is a treated 4 x 4 post at least 3 feet in the ground (or more) and back filled in with gravel.It is out of the ground around 6 + feet, but low enough so that I could reach the top when standing firmly on the ground. About a foot from the top of the post I attached two 10 foot ~ 2+ inch pvc pipes with a long bolt through one pvc, then the post and then the other pvc to make a hinge. Another long bolt close to the top of the post to firmly attach the pvc pipes to the post. By pulling one of the bolts, I can lower the pvc pipes to the ground. Then I used a fiberglass tube, a bit more than 10 feet long and attached it with two bolts to the top of the two pvc pipes which are now much closer together than where they are attached to the post down below. This gives me well over 20 feet.

Because I experimented with many ham antennas on many different (mostly) HF frequencies over the decades I found that this support works as well as, or actually, better than, the typical expensive commercial vertical such as the Butternut HF-XV series. I can run parallel wires for different bands and top the fiberglass part with a CB whip which just made it to 33 feet at the tip. That gives me 40 meters. Then shorter wires for other bands, such as 20, and 30. Because this is effectively a vertical HF antenna, it needs radials, so I put down a bit over 30 radials with some at 30 and some up to 100 feet long. The antenna is around 150 south of the house and I put it that far out because of the radiation pattern impinging on the house and the clearance for the radials. I have swapped out the home made antenna with a Butternut, and after a number of years, put the home made support back. With the Butternut, which is much shorter, I had to use some guys as the antennas is not robustly made. I do not use guys with the home made support although being on the ridge here in the driftless area of Wisconsin we get a lot of wind and the support does tend to lean away from the SW.

Using pvc for both the bottom and top sections I found to be too flimsy, thus the fiberglass tube. You could also use EMT or aluminum tubing. 

 

For GMRS use, you would want to have the post much closer to the house to keep feedline loss to a minimum. Since the GMRS antennas are so lightweight, they would not be too much of a load, even a gain vertical. 

I might mention that what I use for GMRS antenna support is 30 feet of Rohn 25G plus another 10 foot pipe. This has a house bracket at 12 feet on the end of the garage. No guys.



#8 gman1971

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Posted 21 April 2020 - 05:02 AM

Hi, I have a large 25 foot 1 1/4" metal pipe bolted on the side of my house using the 1st floor roof as a starting point. Until this past week it was never guyed it, and it has survived 40-50 mph winds without much of an issue for almost 3 years...  Lately Its been super windy and since I am stuck at home I've seen the mast swaying, nothing too crazy, but I figured I'd add a couple of guy wires to it just in case.

 

I think if you mount it well and the pipe is strong enough guying is probably not needed for anything 40 feet AGL under... unless you live in a place where winds are regularly stronger than 50 mph... then I certainly would've guyed mine since day 1.

 

G.



#9 russwbrill

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Posted 23 April 2020 - 12:39 PM

Here's a source for Mounts, Guy Wire, and Masts https://www.channelm...ories_s/359.htm

 

Much better than chain link fence posts :)



#10 Kugellager

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Posted 26 April 2020 - 08:59 PM

I have built a number of temporary and permanent antenna masts using fence top-rail and heavier gauge fence post. I would suggest securing the bottom two feet to house using a sturdy mount and negate the extra two feet mentioned in you post. I think 20' of top rail by itself will be ok with your very light antenna...More than that I would not go.

 

John

];')






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