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Author Topic: Multiband Vertical  (Read 2137 times)
WB4CMB
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Posts: 39




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« on: January 18, 2013, 06:38:15 PM »

I am very interested in building this multi band vertical as printed in ARRL's
 “Simple and Fun Antennas” titled "WA5ABR's Homebrew Seven Band Vertical.

It is a multiband vertical with parallel feed (only one coax feeding all elements), using aluminum elements and plexiglass to "support" and seperate the seperate vertical elements.
 I own a 259 Antenna Analyzer.
 
If you have not built this, what do you think of it?
 H
 Has anyone built this antenna? If so:
1. Are you still using yours?
 
2. Any problems with interactions between the vertical elements?

3. I was also considering using two or more separate feedlines, I have
read where this would reduce interactions.

4. Mainly I am interested in 40, 20. 15 and 10. For 40, I would either
have 25 ft vertical and capacitive top loading (prob about 4 ft diameter top
hat) OR use a full sized vertical element.

5. I am also considering adding 75 by using somewhere between 25 and 35 ft
vertical and the rest of the 75 meter wire horizontal (inverted L).
 
7. How about adding a vertical element for 6 meters?
 
I am an older ham who is trying to get back up on the air. The city I live
in, Aurora, CO, does not have any inspections or requirements for antennas 25 ft
and under. For anything over that, a Colorado certified Engineer must sign off
on antenna plans, and 35 ft high is the max.
 
I also own a cabin in the CO mtns and need an antenna there. Restrictions
there are much easier but there is still a county limit of 35 ft. I have a
neighbor up there who has all ready sent me a nastygram Email and I don’t even
have anything up at cabin yet. I have an HOA there but no antenna
restrictions. I have a thread on both QRZ’s Antenna and Eham’s forums on
this.

Thanks Ray WB4CMB
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WB4CMB
Member

Posts: 39




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« Reply #1 on: January 18, 2013, 08:02:17 PM »

I did not intend to just simply extend the 40 meter element to use on 75, knew that would not work. Maybe could use a 40 meter trap. (Would reduce bandwidth somewhat)
 I was planning on adding an extra vertical element (since I did not plan on using all the elements for all the bands, there would be room)and then attaching a wire to make the inverted L.
 On further thought, I would probably be better off doing a seperate 75m antenna. Even then, it would prob react a lot. But I need 75 and my back yard/lot is very small. I was hoping to get a much larger bandwidth for 75 than fm most commercial antennas, maybe a larger bandwidth on other bands too
 Plus I need to "play" with my 259, LOL. Seriously with all the changes I mentioned, I might have a "goat rope" on my hands.
Thanks Ray
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AC4RD
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Posts: 1235




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« Reply #2 on: January 20, 2013, 07:13:08 AM »

Ray, I'm not familiar with the specific antenna you mention.  But over the last couple of years I've done a lot of playing with homebrewed verticals, using those mil-surplus fiberglass poles as masts, and aluminum tubing elements, one per band I want to cover, just cut to a standard quarterwave length for that band.  I don't think I have any photos of these on my website right now but I can dig some up if you're interested.  Single coax feed, tubing elements tied together electrically at the base of the antenna, elevated radials.  I've had GREAT performance from these antennas, and they've been fun to experiment with as well.  The only reason I don't have one up now is that I'm using the mast for a little 10m yagi.  So I'd say the basic idea is sound as a bell, and if you like experimenting and homebrewing, this is a very fun and rewarding type of antenna to play with!   73 GL!   --ken   (ps--shoot me an email if you want to see some pics of my verticals)
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WB4CMB
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Posts: 39




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« Reply #3 on: January 20, 2013, 10:22:15 PM »

Ken, I would like to see your pics.  When you used the fiberglass poles, did you use wire with them? 
Are the surplus poles heavy?  How expensive are they?      Thanks     Ray
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W5WSS
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Posts: 1721




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« Reply #4 on: January 22, 2013, 07:53:10 AM »

Hello, yeah I have also been making allot of quarter wave verticals.

I suppose one can include separate vertical radiators pushing against a series of ground mounted radials for multi band use ...But the 6BTV is very cost effective, and everything else being purchased for either approach, radials, support structure etc

The quarter wave presents radiation field strengths that are very useful to the ham that is needing an effective and stealthy antenna.

The quarter wave in conjunction with a multi band design presents very useable Rr at the feedpoint.

The Aluminium tube quarter wave ground plane and a variant quarter wave vertical with wire quarter wave sloped radials has been very gratifying and a known performer relative to skywave long range communications.

The latest version I built and using cost about $20.

73
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AC4RD
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Posts: 1235




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« Reply #5 on: January 22, 2013, 09:16:49 AM »

Ray, shoot me an email and I'll send some pictures to your email.    --ken ac4rd
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EI2HPB
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Posts: 39




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« Reply #6 on: January 22, 2013, 03:10:49 PM »

Heres another simple and interesting multiband vertical worth experimenting with... got the measurements from a German station I worked who was using one and I built it myself to try it out... This is a wire vertical, I used 14 awg multi strand as its what I had in the shed... so the vertical element is 6.5m (21ft 3") and you can use whatever you have to get that in the air, I used one of those push up fibreglass poles... then there is a counterpoise of exactly the same lenght 21ft 3" drooping away from the vertical at aprox 40 degs and heres the quirky part... both of these wires are fed by a 5.5m (18ft) section of 450 ohm ladderline which also needs to drop away from the vertical at approx 40 degs... you can then connect your regular 50ohm coax to this section of ladder line and on to your radio or antenna tuner... I had mine mounted in a couple of TV brackets on the gable of the house with the base of the vertical wire at about 20ft from the ground... the counterpoise and 450ohm section were tied off on a fence and in my case I only needed to run about 20ft of coax to the shack... on checking, the SWR was lowest on 20m, about 1.2 across most of the band, surprisingly it wasnt too high on 40m, about a 2 at mid band (7.150) and the tuner in my FT1000 MKV flattened it easily... same on 10m... SWR on 15m was about a 3 and the same on 17m so again easily tuned with most radio tuners and certainly any cheap external tuner... Anyway my first CQ call on 20m resulted in a 5/9 report from a station in Algeria and I went on to have some great DX contacts on 20 including some West Coast States and BC in Canada... thats proper DX coming from Ireland! On 40m it worked surprisingly well with contacts all over Europe and Russia and a few into the States... didnt try 10 as the band was dead... worked some EU on 17... Unfortunately a couple of weeks ago a storm took the antenna down and smashed the pole to pieces, weather has been very rough since but I fully intend to put the antenna back up fairly soon but make it much more robust this time... the whole thing cost me the 30 bucks I spent on the pole... by the way I dont run an amp so power output was 150w from the radio for all of these contacts... the statisfaction of making contacts with such a simple to make cheap antenna left me with a big grin on my face  Grin
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WB4CMB
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Posts: 39




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« Reply #7 on: January 22, 2013, 09:15:02 PM »

Ken,
My Email      RaymondParkII@msn.com
Thanks     Ray
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