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Author Topic: Mosley CL-33 Beam in Attic?  (Read 531 times)

K8LEC

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Mosley CL-33 Beam in Attic?
« on: August 02, 2020, 12:55:06 PM »

I am just getting back into the hobby after a 14 year hiatus.  Just ordered an Icom 7300 and am excited to get back into the hobby.

One of the reasons I left the air was due to moving into a new home in a subdivision with some antenna restrictions.  I did keep many of my antennas though and they've just been sitting in my garage ready for a day to be used again.  One of them in particular is a Mosely CL-33 beam, which I had on a 35ft tower at my previous residence. 

I'm thinking of putting that up in my attic, where I have lots of room and could angle it towards the majority of the US to at least be able to use it rather than it sitting gathering more dust.  I'm wondering if anyone has put an antenna like that in an attic and how the results have been.  My attic is pretty bare and has no ducts or anything in it.  Just blown in insulation, and rafters.  The antenna would likely be around 12-14 ft above the ground when mounted in the attic.  Just wondering if it's worth it or if the results would be so poor it would be better to skip and just go with a dipole or something? 

Thanks!
Lars
K8LEC
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K1VSK

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Re: Mosley CL-33 Beam in Attic?
« Reply #1 on: August 02, 2020, 01:40:12 PM »

Biggest question is how any antenna may interact with all the wiring present in any attic. Easiest way to tell is put up the driven element and watch how the impedance and SWR changes as you move/rotate it.
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K0UA

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Re: Mosley CL-33 Beam in Attic?
« Reply #2 on: August 02, 2020, 03:19:42 PM »

It would be interesting to see how well it works. Put it up and give it a try.  You must have one heck of a huge attic to put a CL-33 in it.  :) 

It wouldn't surprise me that it would need some serious adjusting to get a match on each band, but again it would be an interesting experiment.
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73  James K0UA

K6AER

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Re: Mosley CL-33 Beam in Attic?
« Reply #3 on: August 02, 2020, 03:57:30 PM »

The proximity of house wiring Is going to greatly affect the antenna tuning. Are you going to rotate the antenna? The interference from household electronics is going make operation very hard.

Good Luck
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K8LEC

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Re: Mosley CL-33 Beam in Attic?
« Reply #4 on: August 02, 2020, 05:27:12 PM »

Thanks for the replies.  Our house is about 50ft by 30ft or so with a garage that is 24ft by 24ft.  Above all of that is a pretty big attic with not much "stuff" in it.  So I do have a lot of room to do some antenna installation.  There are trusses however so I won't be able to rotate the beam, no.  I planned to just point it towards the southwest, giving me the majority of the US from my QTH in MI.  No doubt the antenna won't function as it would on a tower like I had at my previous home.  And I'm sure the tuning won't be as specified by Mosley. But if it can do half as good as it did before, I'll be happy.  Plus right now it's just disassembled, hanging on the wall in my garage.  So I figure, why not give it a try. I hate seeing an almost $1K antenna going unused.  I'm also going to put a Hy Power, off center fed 80m antenna outside my house between some trees, so I'll have that for comparison and use as well. 

I'll definitely post back once I get it up and running.
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NN2X

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Re: Mosley CL-33 Beam in Attic?
« Reply #5 on: August 02, 2020, 06:16:34 PM »

Go with a HEX Beam, K4KIO, nearly the same gain, but far more smaller..

Cheers

NN2X. Tom
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K5ML

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Re: Mosley CL-33 Beam in Attic?
« Reply #6 on: August 02, 2020, 06:34:21 PM »

I agree with Tom on trying the hex beam. It has about 3' of vertical height but the turning radius is less than 11'. You might be able to rotate it in your attic or hide it on a mast in your back yard. I live in an HOA restricted community and have a KIO Hexagonal Beam mounted on my patio roof. Check out the pic on my QRZ.com page.

73,
Mickey, K5ML
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K8LEC

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Re: Mosley CL-33 Beam in Attic?
« Reply #7 on: August 02, 2020, 07:02:44 PM »

Thanks for the tip on the Hexbeam guys. I've not seen that design.  That definitely looks like a possible option down the road, especially if the antennas I have already don't cut it.  Again, I have the CL-33, so I'm not spending anything but some time and effort to give that a try.  I just wondered if anyone had ever tried putting a beam like that in an attic and what the results were. 

But the Hex looks like a great design. Maybe I should sell the CL-33 and go for something like that? I'll bookmark that page and keep it in mind for sure!!
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K4VV

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Re: Mosley CL-33 Beam in Attic?
« Reply #8 on: August 02, 2020, 09:44:48 PM »

Hi Lars,
I am currently experimenting with a Cushcraft A3S in the attic above my garage, with some interesting results.  I just sent a detailed email to you via the address on your QRZ page, but it is not going through.
Dave - K1EUS
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K8LEC

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Re: Mosley CL-33 Beam in Attic?
« Reply #9 on: August 03, 2020, 04:30:24 AM »

Hi Lars,
I am currently experimenting with a Cushcraft A3S in the attic above my garage, with some interesting results.  I just sent a detailed email to you via the address on your QRZ page, but it is not going through.
Dave - K1EUS

Sorry about that Dave. My email provider apparently had an issue I didn't realize. I fixed things so it should work now. I also have a different address up on qrz now so either should work. Love to hear your experiences!

Lars
K8LEC
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KL7CW

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Re: Mosley CL-33 Beam in Attic?
« Reply #10 on: August 03, 2020, 11:29:09 PM »

Lars,  I do think it would be worth a try since you already have the CL33.  One thing I have found out in 66 years as a ham is that sometimes antennas work much better or worse than you expect.  As suggested, you could just put up the driven element first to get a rough idea if there is any chance of success.  The driven element alone will probably have a higher Z than the Yagi, but for a RX test do not worry about that or adjusting the element.  If it looks like it might work, then try TX, possibly at low power if the SWR is high. A Yagi has nulls in various directions, and RX noise may be your biggest problem, but even rotating the antenna 10 degrees may null out nasty noise from a neighboring house.  If it seems to work, and you need a little more room to rotate, possibly the Yagi would still work OK if you bent the elements down say 10 to 30 degrees perhaps 2 or 3 feet out from the center, so each element would be a flat top inverted V.  You could possibly just replace a section of each element with piece of bent aluminum. You can eliminate SMPS and other noise in your house with some ferrite and effort, but who knows about neighborhood sources.  Often, but not always, noise is much worse on 160, 80, and 40, than on 20 through 10 meters.  The Hex beam idea may be the way to go, but experimenting with the Mosley first may save some money. Try to keep the ends of the elements as far away as possible from the structure (I know this is impossible). Plan on spending some time in the attic, since much adjustment may be required on this multiband antenna, and the structure may detune it so much that it would be nearly impossible to get all three elements tuned correctly on all bands. Another idea you could consider, build it up as a two element Yagi. Adjust the driven element.  Then adjust the reflector for minimum signal off the back.  This adjustment often will get you very close to the maximum forward gain, but is much easier to do than tuning for best forward gain.  Probably a test signal as close as 50 feet would even work.
   No guarantees that any of these things will work, but these are just a few of many ideas to think about.  Good Luck, Rick KL7CW
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KX2T

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Re: Mosley CL-33 Beam in Attic?
« Reply #11 on: October 01, 2020, 07:38:12 AM »

First off the CL33 is a tri band antenna and what ever gain it has is limited in the bandwidth that it might have were it really will deliver that gain at, beams are a much higher Q antenna then a wire type semi quad style antenna so the lower Q of the Hex Beam will work better surrounded by other close by house wiring but still the further you get any antenna away from the ac or what ever wiring you have below it the better they will perform. Either keep the CL33 in storage until the time you can mount it outside properly of sell it, the hex is smaller and will be less effected by the near by wires in your attic space. The CL33 is one of the better three element trapped tribanders when it is installed properly away from other metal type objects and the attic thing would sourly effect it performance.
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K8LEC

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Re: Mosley CL-33 Beam in Attic?
« Reply #12 on: October 01, 2020, 07:55:57 AM »

Well, interestingly enough, I decided to go forward with a 37ft tower and put the beam up in all its glory.  :)  I actually just got it mounted this past weekend.  Given I didn't have any specific HOA restrictions, I felt it would be fine and not a problem. All of my immediate neighbors are intrigued as I've talked with them, not annoyed. My wife was on board all along but when I put the beam up, I think she did a double take at the size.  But she's good, the neighbors are good, and I now have my CL-33 back and ready to go.  Still working on getting all of my coax feeds into the shack, but I'm excited to see it in the air!! 

Here's a pic. On top of CL-33M I put 2, 4 el 2m beams in a phased array, and a GP-3 2m/440 vertical on top.  The dipole off the side of the tower is an 80m off-center fed antenna. 

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K0UA

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Re: Mosley CL-33 Beam in Attic?
« Reply #13 on: October 01, 2020, 08:24:22 AM »

Well there you go.  Looks great, and I am sure it will work great too.

73  James K0UA
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73  James K0UA
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