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Installing a 5/6 BTV on an Airstream

from G.M. Amthor, WA6CDE on June 20, 2015
View comments about this article!

Installing a 5/6 BTV on a RV Airstream

Designed By G.M. Amthor, WA6CDE (1971)
(Rev 2015)

I got real tired of seeing my design that others claim that they came up with for the Airstream RV antenna mount. I decided that I would again show others what I came up with in 1970's and some of the improvements that now are incorporated in MY original design. (Yes I know that the ARRL published MY design in a article, written by an 8 call person, that had copied mine without permission. I originally wrote the article and showed others at the Airstream Club rally how to make one. I designed this antenna installation and through the years made improvements' to it. I will show all some of the improvements made to the antenna design and continual revisions to it.

A Deluxe RV 5-Band Antenna

This antenna was designed to be mounted on a 31-foot Airstream travel trailer. With minor changes it can be used with any other recreational vehicle (RV).

Perhaps the best feature of this antenna is that it requires no radials or ground system other than the RV itself. (Airstreams are made from good grade of aluminum.)

The installation involves the use of a Hustler 5/6BTV vertical with the normal installation dimensions.

The modified antenna is mounted on a special mast that is hinged near the top to allow it to rest on the RV roof during travel.

How To Make One

The secret of the neat appearance of this installation is the unusual mast material used to support the antenna. Commonly known as Square tubing, it is often used to make fences, desks, other projects. The size selected is 2 x 2 x 0.125-0.250 in.

The material is an extremely tough steel that resists bending but is very easy to cut, drill and weld. It should be painted when finish to prevent rust and corrosion; it may be painted to match any RV color scheme.

The supporting mast is secured to the rear frame or bumper of the RV by means of bolts but, we prefer the adaption of a angle bracket that would fit into a common 2x2 trailer hitch receiver.

(Rev 2: we had 2 welded on the frame which extends to the bumper of the trailer.)

These can be used for other items such as bike mounts, accessories', etc. when not used for the antenna mount.

Here is the typical angle mount for the antenna/car.

Or a second type (Rev 2) of these which can also be adapted for the center section fold over that contains a stop which with modifications by reversal or extension of the tube becomes the center fold over.


Any of these brackets can also be used for the tow vehicle trailer hitch mount also.

Any brackets mounted higher will require a change of dimensions.

Typical Antenna Mounting

Originally we install the antenna on the curb side of the vehicle to hide the lowered antenna behind the RV awning and provide greater safety to the person raising the antenna. This precaution is primarily for safety when stopping alongside a highway to meet a schedule. (Cautionóbeware of overhead power lines!) (NOTE: Revision 2-- Mounting the Hustler on the Road side of the trailer keeps it from interfering (tearing) the RV awning)

Mounting the Hustler The 4BTV antenna base is 2 bolts through a 19-inch piece of sq tube that makes up the flop over section above the welded (or bolted) hinge. A single ball lock bolt in the bottom position or two bolts causes the fold over section to become ridged. Be sure to run ground strapping across all joints (see drawing)

(Rev 2.)

Instead of one long piece of 2x2 and making the hinge fold over on the end it was found that welding the fold over section (to a 6 inch piece, which is the worked hinge part, was easier to build).

The addition of the fold over bracket on the bumper allows one to fold the antenna back for easier adjustment.

The top-hat spider rods should be installed ridged only on one side of the antenna so as not to poke holes in the top of the trailer. The other sides are made so as to fold back away with longer screws, springs and washers. (See drawing)

No effect on antenna performance will be noted.

Bring the coaxial cable into the trailer at a point close to the antenna. It is recommended that a choke balun wound of 10 turns or other means be used at the base (feed point) of the antenna to keep RF feedback from getting into the trailer. Be sure to use drip loops the point of entry into the RV. Silicone rubber sealant should be used at the outside connector end and at the RV entry hole.

A good place to put the Coax is to follow the trailer frame inside the C section. However, it can be placed in support holders on the underside of the trailer also. Great care should be taken to obtain a good ground return from the antenna all the way back to the transceiver.

Heavy duty tinned copper braid, should be used across the mast hinge, the mast-to-RV frame and to bond the frame to the equipment chassis. This is absolutely necessary if the vertical quarter-wave antenna is to work properly.

Antenna Pruning and Tuning The antenna must be carefully tuned to resonance on each band starting with 28 MHz. One can use a antenna analyzer such as the 259 for quick simple tune up. It is a good idea set the tuning for the center of each band. Tuning of the antenna as described will resulted in an SWR of 1.5:1 or lower at resonance on the 3.8, 7.15, 14, and 21-MHz bands.

This system design also provides full band coverage on the 7 through 28-MHz bands with an SWR of less than 2:1. Band coverage on 3.8 MHz is limited to approximately 100 kHz because of the short overall length of the resonator coil and whip. The tip rod is adjustable to enable you to select your favorite 100-kHz band segment.

Note:

Ground radials can be attached to the rear bumper extending out from the back of the trailer for better impedance of the antenna.

One can add the 30 meter portion to the hustler antenna so that it becomes the 6BTV with little or no modification.

Concerns of the antenna movement when folded over on the roofline of the trailer when under tow can be reduced with the addition of a support at the fold over hinge point and/or providing a spacing away from the trailer body and/or by using some of the Teflon material such as a cutting board. One also then could use a hold down strap at that point so that the antenna won't bounce up or do damage. Access to this spacer/hold down can be achieved with a small ladder or some other means.

Member Comments:
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Installing a 5/6 BTV on an Airstream  
by N6JSX on June 20, 2015 Mail this to a friend!
Interesting - only issue with the article are the drawings print/font is to small to read - I tried to zoom in but then the dwg resolution just becomes a blur.

Over the years I've had many of my 'J' articles plagiarized and they didn't even change the dimensions (fractions or decimal to metric) to hide their redo.

If you want to add 17m and improve your overall performance a little consider the Ugly-Balun (really an RF choke - decoupler) it sure helped me with my 1980's 18AVT resurrection project to place on my new chain-link fence - works great now. (see my two eHAM 18AVT articles posted here last year).

So the antenna is actually above the hinge with the bumper extension acting as part of the counterpoise.

Need to insure the antenna "when laying down" is no higher than 11.5' from road surface or you might kiss low bridges/overpasses/trees. And yes I would strap it down to the roof to minimize any bouncing.

Kuby, N6JSX /8, MS-EET
 
Installing a 5/6 BTV on an Airstream  
by K7LA on June 20, 2015 Mail this to a friend!
Thank you for the article.
As a word of advice to technical authors, please copyright your intellectual property. If someone steals your material and publishes your hard work, you have recourse available.
 
Installing a 5/6 BTV on an Airstream  
by JOHNZ on June 20, 2015 Mail this to a friend!
@K7LA

Your copyright is virtually worthless, unless you register it, meaning you have no legal recourse, unless you register your copyright.


 
RE: Installing a 5/6 BTV on an Airstream  
by N0YXB on June 20, 2015 Mail this to a friend!
I'd never heard that one before, and I found this info about copyrights on the Wikipedia, for what it is worth.

"Copyright is automatically granted to the author of an original work (that otherwise meets the basic copyright requirements, discussed above). Registration is not necessary. However, registration amplifies a copyright holder's rights in a number of ways. Registration is required before a lawsuit can be filed, and registration creates the possibility for enhanced "statutory" damages.

A copyright can be registered online at the US Copyright Office's website. The Copyright Office reviews applications for obvious errors or lack of copyrightable subject matter, and then issues a certificate of registration. The Copyright Office does not compare the authors new work against a collection of existing works or otherwise check for infringement."
 
Installing a 5/6 BTV on an Airstream  
by JOHNZ on June 20, 2015 Mail this to a friend!
@N0YXB

Reread what I posted, then reread what you posted. We are both on the same page, and we are both correct. No disagreement.

Allow me to give a -hypothetical- case, in order to explain in a different way what I said. John Doe publishes a tech article, which is then used verbatim by Jack Anybody who represents it as his original material. Mr Doe informs Mr Anybody that he (Mr Anybody) is to cease using Mr Doe's material and also should publish a correction that the tech article is based on Mr Doe's original material. Subsequently, Mr Anybody tells Mr Doe to take a flying (you know what) and to go to (you know where.) Now very angry, Mr Doe feels powerless to stop Mr Anybody from stealing his (Mr Doe's) original material, so Mr Doe files a lawsuit against Mr Anybody for copyright infringement. The case comes before the judge, and the judge asks Mr Doe where the papers are to prove he registered his original work. Regretfully, Mr Doe said all his friends on Eham told him he did not have to register his original work. Subsequently, the judge rules against Mr Doe and tells Mr Doe the case is dismissed, because Mr Doe never registered his original material. Good news though, because the judge informs Mr Doe that he should immediately register his original work with the copyright office, in order to prevent any future copyright infringement by Mr Anybody. Mr Doe follows the judge's advice, and when Mr Anybody continues to infringe on Mr Doe's original (now copyright registered) material, Mr Doe once again file suit against Mr Anybody. This time the judge throws the book at Mr Anybody, and Mr Doe wins his law suit.

Moral of the story, don't seek free legal advice on Eham (which includes from me). Retain a good attorney, when you need legal advice. I work in commercial broadcasting. When I require legal advice, I go to our legal dept.

 
Installing a 5/6 BTV on an Airstream  
by K7NSW on June 21, 2015 Mail this to a friend!
There are two parts to this article. Part one is the antenna mount. Part two is the history of the intellectual property infringement, the information about patents, and the warning to never follow any advice you read on eHam.net. Of the two parts, I am not sure which one I like better!
 
RE: Installing a 5/6 BTV on an Airstream  
by K6CRC on June 21, 2015 Mail this to a friend!
Anyone wanting to protect anything needs to know the difference between Trademarks, Copyrights, and Patents. All terms were used in comments. Wikipedia, while a good source of knowledge, is not the expert...

Also, just because you have 'protected' something that doesn't mean much unless you are willing to put the time and money into followup. How much are you willing to spend to 'protect' that widget you feel you designed? Do you know how much a specialist lawyer costs per hour? How long these things take to get through the courts.
 
Installing a 5/6 BTV on an Airstream  
by K5AF on June 22, 2015 Mail this to a friend!
The real question: How well does it work?
 
RE: Installing a 5/6 BTV on an Airstream  
by KC0JEZ on June 23, 2015 Mail this to a friend!
While it is quite true that you must register your copyright to collect any damages from infringers, the copyright violation is still a criminal offense, and the infringer will be liable for fines, even jail time. So, yes, there is still recourse for the original author, if realizing the infringer had to go to court and pay fines.

Even if registered, in the lawsuit you will need to show actual loss. How much did QST pay for the article 40 years ago? What are the chances that an article that old fell into public domain (there are a few quirks in copyright law where that is possible).

A registered copyright may protect you -- the lawyer will want several thousand upfront and the lawsuit would probably take years. All to prove that the article you got paid $20 for in 1971 was infringed upon, that you really stood to gain nothing from it in the future, and you get nothing.
 
Installing a 5/6 BTV on an Airstream  
by JOHNZ on June 23, 2015 Mail this to a friend!
@KC0JEZ

Yes, take them to Copyright Court and lock them up for 25 years to life for this serious "crime."

Joe make copies of Jack's tech article and handed them out under his own name. Tactical copyright teams responded within minutes.

 
Installing a 5/6 BTV on an Airstream  
by K5HRV on June 23, 2015 Mail this to a friend!
I look forward to buying my family's first RV in the next year or two and think I'll put your antenna on it as well. I'll probably etch your name and call on the side of it, so at least you'll get some credit that you're due! :-) Thanks for the article.
 
Installing a 5/6 BTV on an Airstream  
by KK4NXY on June 24, 2015 Mail this to a friend!
While you did sort of credit the author, this is definitely lacking a proper bibliography. All ^this^ is a slippery slope, one not to get caught on.
I mean to advise, not offend, sorry if I do the latter.
 
RE: Installing a 5/6 BTV on an Airstream  
by KK4NXY on June 24, 2015 Mail this to a friend!
Gah, my wording went out the window on that one, nevermind
 
RE: Installing a 5/6 BTV on an Airstream  
by BOYSCLUBRADIO on July 1, 2015 Mail this to a friend!
Indeed!!! the base mounts are usable on other types of antennas. We built several for the ECOM trailer and used them on the back of it. Did what was suggested and put two(2) of the trailer hitch recievers, one on each side of the frame to the rear.

We use a inverted V on one and UHF/VHF antenna on the other.

When we travel we simply remove the hitch by removing a single bolt (like he suggested in his drawings) and put them in the trailer storage rack on the back bumper.

He did a article on the usage of the 5btv not only for the vertical but also as a support for dipole and inverted V antennas.

So you don't have to use the hustler 5btv the mount is adaptable to other elements.

Good luck. Ours seems to be quite acceptable for the type of resonator used.
 
RE: Installing a 5/6 BTV on an Airstream  
by W7WQ on July 4, 2015 Mail this to a friend!
ZZZZZZZZZZZZZZZZzzzzzzzzzzzzzzzz
 
Installing a 5/6 BTV on an Airstream  
by KE4ZHN on July 25, 2015 Mail this to a friend!
This would make a killer mobile antenna till you go under an overpass. :-)
 
Installing a 5/6 BTV on an Airstream  
by KE4ZHN on July 25, 2015 Mail this to a friend!
This would make a killer mobile antenna till you go under an overpass. :-)
 
RE: Installing a 5/6 BTV on an Airstream  
by W5HEH on July 28, 2015 Mail this to a friend!
Having grown up with a Family RV Biz, i relate to this article with Nostalgia and interest . Thank you to this creative Author who has continued to share good usable info as ,"Open Source ",even tho others have stolen ideas and use .
We also have to pay attention to Grounding which i have found from asking many questions from Mobile Ops. Also learned the mounting location of your antenna is paramount for best performance , ie: front mounted Vertical or even mounted independent on a Base separate from the RV . Happy RVing, 73s
 
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