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Author Topic: Fishing pole mounting...  (Read 2187 times)
G6KIZ
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« on: October 15, 2007, 04:16:22 AM »

It was a bit of a tossup which section to post in but here seemed as appropriate as anywhere else.

I currently have a G5RV mounted fairly low and doglegged to fit available space and was looking to improve it. I bought a couple of 10m (32ft) fibreglass fishing poles initially with the intention of raising the G5RV however after some research I think I can do better. I intend to use the poles to mount a vertical 40m fullwave loop fed halfway up one of the verticals. I will use the G5RV plus some extra wire to make it up to the require length. I hope to use on 40m 20m and 15m through a tuner. I can sort out the electrical part of this OK using website descriptions, EZNEC, and an antenna analyzer.

My question is on the physical aspects of mounting a 10m fishing pole vertically so it has some chance of staying up. I'm pretty much certain that the bottom section will not be strong enough to use U or V bolts so I'm inclined to zip tie the pole to a 2inch square fence post using maybe half a dozen or so ties over a 2 foot length. The fence post would be fixed in the ground using a metapost (metal spike about 2 feet or so long with a square socket the post fits in). I'd prefer to avoid guys.

So has anybody mounted a fishingpole without guys and had it remain upright?
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K1CJS
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« Reply #1 on: October 15, 2007, 06:46:52 AM »

The poles are too flimsy to stay upright without them if you're using a heavier wire, especially in a wind.  It may well be worth your while to tie them back, even using light polyester cord to a couple of fixed points, to support the top part of the loop.  If there aren't any fixed points you can easily use, a couple of tent stakes (longer ones) can be used to hold the ends of the cord.  You can pull them easily enough if need be and reinsert them afterwards.
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N3OX
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« Reply #2 on: October 15, 2007, 07:34:52 AM »

I agree with K1CJS, you're probably going to need some guys at the top.... all the fiberglass poles I have, from cheap fishing poles to the heavy duty Spiderbeam ones are very flexible and can't take a whole lot of side load and stay upright. The Spiderbeam ones are *better* but still have tons of flex.

You might be able to support a span of horizontal wire if you incline the poles outward at the top so they bend over like this :

http://n3ox.net/files/2017delta_lg.jpg

As far as attaching the bottom, I've had pretty good luck with the use of zip ties.  That's what I use to fix the spreaders to the aluminum hub on my Moxon.

http://n3ox.net/projects/2017moxon/

I think I have eight ties per spreader for the 16' poles and the poles are the weak point and would break before the ties break.  I think you're right that they're a good solution because they spread out the clamping force over a large area and won't crush the pole.








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73,
Dan
http://www.n3ox.net

Monkey/silicon cyborg, beeping at rocks since 1995.
G6KIZ
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« Reply #3 on: October 15, 2007, 07:54:35 AM »

Thanks for the thoughts.

I'm glad to hear that zip ties are reckoned to be good enough for the lower mounting as finding something the correct diameter to plug the hollow end to allow the use of U bolts would have been a nightmare.

The concensus that guys will be needed isn't welcome but not overly surprising - those poles waggle pretty good with no antenna at all. I can probably arrange some inline guying quite easily but side on will be a problem (with the xyl mostly).

As the main mountings have not had adverse comment I think I'll do a bit of suck-it-and-see. If it doesn't work there is no huge loss.
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G6LFT
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« Reply #4 on: October 16, 2007, 04:40:44 AM »

I use three 10m poles (from Sotabeams) to support a 40m full wave horizontal loop - however, I do not use the top two sections as they are too flimsy. The wire is very light (0.7 mm enamelled copper if I recall correctly).  It has been up for two years and performs quite well.  I did have a vertical loop for 30m similarly supported but it did not work well on other bands (see Cebik on this subject  http://www.cebik.com/scv/vdelt.html ).

Previously I have had the lower section of a fishing pole fail when I used a wooden clamping arrangement (it was also a very cheap pole).  Now I bind the poles to a short support post (or more usually part of my hedge) using wide webbing.  This spreads the load.
73
Graham
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G6KIZ
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« Reply #5 on: October 17, 2007, 01:35:01 AM »

Thanks for your comments.

I've seen both good and bad reports on loops. The page that made me decide to try one for myself was http://ka1fsb.home.att.net/loopants.html - if it doesn't work well then I'll have to decide what to try next.

Mountng a dipole is problematic for me as the house sits on one side of the plot plus I can't easily get sufficient height for any horizontal array to be anything other than a cloud warmer.

I've got the fence posts now and will try to make the time to start on the job this weekend.  
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KE6VG
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« Reply #6 on: October 20, 2007, 09:00:13 AM »

I have 2 of the stronger 32' windsock poles and 2 of the lighter 31' Jackite poles. The Jackite poles are pretty much good for verticals. The 32' green windsock poles support a 40 meter half-square on the side of the house. (great/cheap antenna for 40m by the way) They do flex if the wire gauge is too heavy. I have a full size 40m dipole made of 22 gauge hookup wire with inline slide switches to shorten it for 10-30 meters. (similar antenna is on the AD5X website). The green windsock poles will support that with a run of RG-8x coax to the top. All the poles I use are supported by 3' long pipes driven into the ground about 18" to 24". If you pop the cap off the bottom of the windsock pole they slide right over top of the pole in the ground. Go to the local hardware store and find a pipe that fits. I use chainlink fence posts. They fit almost perfectly. I simply hammer them into the ground and cut off the mushroomed top (from the hammer damage). If you are going to leave them up permanently you might consider some hose clamps or tape to keep the sections from slipping. All my antenna wire and coax are attached to the poles using velcro strips I got off E-bay really cheap. This entire setup makes it easy to move antennas around and take them down in seconds. I just have several pipes driven into the ground in several locations around the edge of the yard. Any one who lives in a antenna restricted area can easily put up a non-compromised antenna with this setup. Verticals, dipoles, loops, that go up when you are operating and drop to the ground in seconds when you are off the air. Or, up at night and down in the day.
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OH5FAD
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« Reply #7 on: November 25, 2007, 12:28:57 PM »

Yes, a single fishing pole is too flimsy to support anything, But buy two and glue them together (one inside another) and you get a surprisingly stiff mast. I made one to support my prototype coil loaded inverted V with good results. No guys required. Just leave two top sections out and use good industrial glue (I used some black stuff that sticks to everything). I fastened the whole thing with just two automotive U-bolts to a two by four plank.

Jukka K
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G6KIZ
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« Reply #8 on: November 26, 2007, 10:29:19 AM »

I found that there was far too much droop on the wires from the poles at the bottom of the garden to the house when only tensioned enough to have a reasonable bend in the poles. The idea of glueing two together is interesting and not one I've seen before.

As a compromise I've put up a vertical triangular loop from a single pole to the house. The apex and feed is around 16ft high, the low wire runs down to the pole at about 8 feet high and the upper one to the pole below the top section - just over 30 feet high. There is a fair old bend in the pole - I've no idea how long it will stay up. The loop is resonant at around 6.2MHz (MFJ analyser) Modelling suggests it should have reasonable low angle radiation on 40m and 20m but is a cloud warmer on all other bands. I've not had time for any serious use yet but I'm considering putting up a vertical of some sort too  - maybe using the spare pole.

I lashed the poles to the fence post with 5 zip ties over about 2 feet of the pole against the post. It was necessary to screw a couple of plastic blocks (the sort used for DIY furniture) on either side of the pole to restrict sideways movement. It's stayed up a couple of weeks but we haven't had much in the way of high winds yet Smiley
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N3BIF
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« Reply #9 on: November 27, 2007, 07:53:25 AM »

A   common technique for using PVC as masting is to take three sections of pipe and clamp them in a bundle. This makes them far more rigid then if left singly so the idea should translate well to fishing poles, even conduit.
    If going with the vertical loop remember it should be at least 1/4 wave high at the lowest point to be effective on its design frequency. So for 40m this would be  about 33 feet above grade, with the top approaching 60-70 feet. I could never achieve this so I found much better results going horizontal.
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G6KIZ
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« Reply #10 on: December 08, 2007, 01:43:03 AM »

Well there's some you win and some you lose I guess.

We had a bit of wind and the pole didn't survive. I'm not sure if this was a freak, a substandard pole, the mounting with zip ties, or what. There was a tree down across the road and it broke an old budlea in my garden too.

http://www.kwikbreaks.ukfsn.org/down.jpg

http://www.kwikbreaks.ukfsn.org/busted.jpg
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