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Author Topic: Stealth beam  (Read 9787 times)
KD4Q
Member

Posts: 54




Ignore
« on: July 23, 2005, 02:11:57 PM »

OK,

I'm stuck in a CCR neighborhood and want to work for serious DX on 20m.

A tower is out of the question.  So, I started wondering, with lots of trees (like 100' deep in at least two directions) I'm thinking I might be able to hide a beam.

Please answer any of the questions that you can. Smiley

1) Can I paint a beam antenna without changing its properties?  I'd like to paint it the color of the trees to help hide it and keep it from shining.

2) Can I mount it with nylon rope between trees, and if so, what special considerations would I need (like, slack to allow for windy days and swaying trees).

3) How much loss am I in for if the beam is below the tops of the trees?  if a lot, I might consider putting it right on top of the trees with a mast tied to a tree, but how much loss will that result in?  (All trees are at least one wavelenght above the ground.)

4)  To pull this off, I am going to need at least 4...for Europe, the Pacific, South America, and Canada (from my QTH of Georgia)...maybe more to try to get Asia and depending on beamwidth.  Is it better to mount them on top of each other, or should I try for differnt locations in the yard.  Is there a special distance between (if stacked) or apart (if not) that would make them work better?

Thanks!
73, Bob, WA4YZA
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AH6FC
Member

Posts: 110




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« Reply #1 on: July 23, 2005, 06:07:12 PM »

Good luck and join the club of those of us, lacking adequate  forsight, who signed away our rights by moving to areas controlled by CC&Rs.  I am certain you will receive lots of very good suggestions, much better than mine.  However, being one also in such a situation I've given it a considerable amount of thought.  

Currently we're designing a garage that has a mansard roof on 3 sides and open on the 4th.  The tower will be located on the back and the antenna will crank down and rest on the roof when not in use, i.e. during the day.  

You might also consider building a vertical beam or phasing verticals. I've been using a Steppir BigIR vertical that is painted to "blend" into the landscaping.  The HOA police have seen it but they know we're moving so they're not complaining yet. Obviously the wire beam would work as well.

One would think that a modest antenna that is put out of sight during the day and used at night wouldn't bother anyone.  Unfortunately the HOA police are not always "reasonable."  If they give you a bad time you could always threaten to put up a nice big TV antenna 12 feet about the top of your house, as allowed by federal law.  It might provide some negotiating room if things go south in a bad way.

Good luck.  I'll be watching the responses you get, I need the advice too!  Hi Hi.

73's

Bill
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WA6YUL
Member

Posts: 53




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« Reply #2 on: July 24, 2005, 01:12:57 PM »

I don't know about a beam but I paint my multi band vertical and 6 meter horizontal loop with Krylon camoflage paint and they are virtually invisible and work fine. I'm also planning on putting up a 17 meter bobtail curtain disguised as a water mister system for the garden (I live where it is hot).
If you can hide it in the trees get a crank up tower, paint it, and only raise it at night.
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W2LO
Member

Posts: 212




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« Reply #3 on: July 24, 2005, 05:41:25 PM »

 I've never used a beam, just a G5RV and now a Cushcraft R-8 but run 300-500 watts if I need it. It's been enough for 5BDXCC and all current entities but two. Time and skill will get 'em for you. Good luck!

                     Mike  W2LO
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WB2WIK
Member

Posts: 20547




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« Reply #4 on: July 25, 2005, 08:10:08 AM »

Sounds to me that you're considering going to an enormous amount of trouble; it would be easier to move, I'd think!

A 20m beam, even a little 3 element one, is a large structure with 30+ foot-long elements and at least a 12-15' boom.  And that's a very small 20m beam.  Four of them installed in a tree or many trees will be a maintenance nightmare, and still won't cover the globe because you'll be missing large areas of the planet where DX is and your beam won't be.  "Asia," for example, requires numerous beam headings, from West to Northeast (through North) from GA -- except during gray line when the long path is often stronger than short path, and to work the Indian Ocean you'd want to be aimed South.  "Africa" is anywhere from NE to SE and one heading doesn't do it.  VK/ZL has its very own beam heading that isn't common with the heading to much of anything else, save some islands nearby -- many of which count as separate DX entities, so you'd want a beam aimed that way, too.

I'd get very frustrated with fixed-aimed beams unless I had an awful lot of them.

A 4-square vertical array with switchable delay lines  might make more sense, and be much easier to maintain.

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WB6BYU
Member

Posts: 13029




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« Reply #5 on: July 29, 2005, 01:42:17 PM »

You can certainly paint beam antennas, but trying to
manage several big chunks of aluminum up in the trees
will be quite a job.  You'll probably need a bucket
truck for maintenance, at the least.

I'd suggest instead some sort of wire antenna.  It
can be threaded through the trees and be very inobtrusive.
A lot will depend on what type / shape / height trees
you have and how close they are together.  But wire
quads are quite inexpensive and can give very good
results.  Sterba curtains, 4-squares, bobtail curtains,
vee-beams and rhombics are other wire antennas that
you might consider, depending on the circumstances.

Or, depending on the shape of the trees, a small beam
(perhaps a Moxon or hex beam) on a rotator might work just
over the tops of the trees if you can keep it low enough
that it isn't obvious from the common access areas.


The most common method of dealing with the trees blowing
in the wind is to run the ends of support ropes over
pulleys and down to counterweights, springs, or other
non-rigid ways of securing them.
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N0VZ
Member

Posts: 26




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« Reply #6 on: August 02, 2005, 08:50:59 PM »

You might consider the Traffie HexBeam.  There is a Yahoogroup with extensive information on the Traffie antenna and for building a homebrew version.  Quite a few folks are using these in a stealth application.
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TORESTEEN
Member

Posts: 21


WWW

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« Reply #7 on: September 12, 2005, 01:49:08 PM »

I have had a "stealth" 20m beam installed on my house for about a year with no complaints (I'm in a CCR sub-division).  I have the Cushcraft "The Director" MA5B up at about 18' tucked in by the rear of my house.  The beam is just high enough to clear the roof edge as it rotates.  I painted it flat black so it blends better with the roof shingles.  It has the RS TV rotor to turn it.  I painted the feed cable the same color as the house so you have to look hard to see them.  From the street they are unnoticeable.

This weekend I just had a 20m QSO with ZK1JD in the South Cook Islands.  I'm in central Florida and the beam was pointing NW, it should have been SW.  I was pushing about 40 watts in a Yaesu FT-840.  While I was weak, it was a solid contact.

KG4SPA

The MA5B is the smallest 20-10m beam I could find and it doesn't cost a lot.  Give it a try.
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WX2S
Member

Posts: 689




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« Reply #8 on: August 10, 2012, 11:07:01 AM »

Sturba curtain disguised as a driving range backstop?  Grin

- WX2S
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73, - Steve WX2S.
I subscribe to the DX Code of Conduct. http://dx-code.org/
STAYVERTICAL
Member

Posts: 854




Ignore
« Reply #9 on: August 10, 2012, 02:59:48 PM »

Why don't you experiment with wire beams as others have suggested.

For example, a half rhombic is only like an end fed inverted Vee with a terminator at the end.
Depending on ground, you also run a counterpoise below the antenna wire about a foot above the ground.
With 100 foot of horizontal run and a 30 or 40 foot tree to support the apex you would have a 20 to 10 metre beam.

The cost is only some wire and a non inductive terminator resistor which can absorb half of your transmitter power.
The military used to use this antenna as a "field expedient" beam antenna in the past.
It is also broadband and should be SWR flat over 20m to 10m, although you will need to match the impedance from 400-600 ohms to 50 ohms, which you could do with a tapered line.

For CCR encumbered hams this must be about the least impact beam I can think of which can give good results.

Another suggestion about a Moxon is a good one as well, although they are normally monoband.
If you have a friendly tree branch, just hang a support rod from it and drop down two vertical wires to make a vertical Moxon.
Then you can just turn it from the ground easily, and it is very low impact visually.
A vertical Moxon's base can be close to the ground and still work, so it is a good easy rotatable beam to try.

It is very hard for HOA commissars to object to simple wires in the trees while tubes are a magnet for complaints.
Remember, many people have been conditioned to expect antennas to be tubular or other substantial objects and are used to hanging wires on poles.

Good luck whichever way you go, 73 - Rob
« Last Edit: August 10, 2012, 03:01:33 PM by STAYVERTICAL » Logged
K1LLR
Member

Posts: 25


WWW

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« Reply #10 on: August 16, 2012, 01:31:13 PM »

GOOD answer..traffie rules,just check out my qrzed page Smiley
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WD4ELG
Member

Posts: 863




Ignore
« Reply #11 on: August 16, 2012, 06:54:20 PM »

Traffie HX5bi, fiberglass poles painted black, suspended at 40 feet between two oak trees with trees behind it.  Very stealthy.  Currently at 302 and climbing.  I also had the HXL-20 from Traffie, even more stealthy, but it was taken out by a falling limb in a thunderstorm.
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KK2DOG
Member

Posts: 25




Ignore
« Reply #12 on: August 29, 2012, 03:45:37 PM »

Get a "QSO King" by Maple Leaf Studios.
It's a great end-fed! Of course an Ameritron
AL-811 doesn't hurt either.




                  Mike KK2DOG
             www.hamwave.com
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N4JTE
Member

Posts: 1154




Ignore
« Reply #13 on: September 26, 2012, 05:44:35 PM »

As others have mentioned, a properly designed pair of wire phased dipoles will get you a big signal into europe and when reversed, a big signal the other way.  See my qrz page if interested.
bob
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K3VAT
Member

Posts: 701




Ignore
« Reply #14 on: September 29, 2012, 02:33:22 PM »

Please answer any of the questions that you can. Smiley
1) Can I paint a beam antenna without changing its properties?  I'd like to paint it the color of the trees to help hide it and keep it from shining.
2) Can I mount it with nylon rope between trees, and if so, what special considerations would I need (like, slack to allow for windy days and swaying trees).
3) How much loss am I in for if the beam is below the tops of the trees?  if a lot, I might consider putting it right on top of the trees with a mast tied to a tree, but how much loss will that result in?  (All trees are at least one wavelenght above the ground.)
4)  To pull this off, I am going to need at least 4...for Europe, the Pacific, South America, and Canada (from my QTH of Georgia)...maybe more to try to get Asia and depending on beamwidth.  Is it better to mount them on top of each other, or should I try for differnt locations in the yard.  Is there a special distance between (if stacked) or apart (if not) that would make them work better? Thanks! 73, Bob,  A4YZA

1.  Yes, you can paint it.  Why not consider camouflage duck tape?  I used this on my stealth Al dipoles and it's great.  Inexpensive too.
2.  Yes, see BYU's para 4.
3.  There is very little loss due to foliage at HF frequencies; starts to be a problem at 6M.
4.  Two yagis in different parts of the yard is a definite possibility, especially if the element ends are separated by > 70 feet or so.  Consider two element reversible yagi's - see N6BT.Com page for reduced-size 2 element yagis - Tom can do a custom 20M for you with performance numbers just shy of a fullsize yagi.  Mount one yagi at 35' for beaming ~ 60 degs for EU and AF.  The reverse side for the Pacific like the current 3D2C and the recent NH8S.  Mount the other yagi at 50' (if possible, 60') beaming 300 degs for the VKs and SE Asia and the reverse will be OK for S AF and some SA.

(I noticed some folks here just posted their preferences rather than simply answering your questions.)

GL, 73, Rich, K3VAT
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