WB3AYW ANTENNAS


WB3AYW HIGH GAIN 2 Meter OR 440 BAND COLLINEAR ANTENNAS

NEW DESIGN YIELDS VERY HIGH GAIN ON 2 METERS OR THE 440 (70CM) BANDS

"Built by a ham for hams"


INTRODUCTION
A collinear antenna is several antennas all fed in phase in a row.

It could be a folded dipole array or just a straight dipole array fed with different lengths and different impedance of coax. It can be made of alternating coax pieces cut to the 1/2 wave length for the frequency.
It can be half wave elements or five eight wave elements, even seven eights wave radiators but fed from one end of the antenna array with phasing coils or stubs between the elements.
A folded dipole collinear array is fed from one point with various lengths of coax and of different impedances. This is the design of many commercial antennas used on repeaters.

By feeding the antenna with the J feed design the only coax needed is your 50 ohm coax from your shack/radio.
The advantages of my collinear design is higher gain than a single antenna and a broader frequency response and very low angle of radiation at the horizon for reaching out much further vs the standard ground plane or J pole antenna types!

The 2 Meter 5 element
 collinear I designed has 9.7 dBd gain
(more than many Yagi types.)
The
2 Meter 10 element
 collinear has a whopping 13 dBd gain
(more than most Yagi types.)

My 70cm 5 element collinear has 9.7 dBd gain
My 
70cm 10 element collinear has 13 dBd gain
All gain is referenced to a dipole antenna!
[Notice all gain figures in dBd, not dBi] 

All antennas are omni-directional, no rotor required!
 

THE WB3AYW ANTENNAS TYPICAL RADIATION PLOT


Typical radiation plot---showing very low 5 degree angle.
 (This plot is typical of both the 2 meter and 70cm versions)

My design uses one half wave radiators and when using five eight wave radiators, after 3 elements, the radiation starts to go very high.
With the half wave elements you can actually stack how ever many you want to, and the radiation angle stays at the horizon or where you set it at.
 
This design was developed as I tried to pull another collinear up in a tree with a rope up to a limb, and the rope kept cutting into the tree limb.
The weight stopped my progress of putting it up.
This prevented me from getting the commercial design up to the height that I wanted.

So I came up with this light weight wire collinear antenna for my repeater in Blairsville Georgia. I now live in the Dawsonville area.
 
It took me a while to develop the phasing coil so the antenna radiated at the horizon.  The first ones were large and very visible.
I kept working on the design.

A couple years later I figured out how to shrink the coils even farther, and this design was born.

Now as for being invisible, (well almost), in deed restricted locations / neighborhoods, painting the coil form flat gray made the antenna almost disappear to people at about 20 to 30 feet away when mounted in a tree. The antenna is very difficult to see as shown in photos below against the shadow of the trees on the wall and against tree and sky backgrounds! "Stealth" depends much on angle of sun, background behind antenna and many other factors.


44605 (70cm 5 element) hanging beside my rv garage in tree

  


Pic 2. (left)  Pic 3 (right)
Pic 2 above....44605 (70cm 5 element) hanging from rv garage door
Pic 3 above....44605 (70cm 5 element) phasing coil on antenna. 
    
                            

 

 Pic 4 (left) Pic 5 (right)
Pic 4 above....44605 (70cm 5 element) laying on driveway
Pic 5 above....44605 (70cm 5 element) phasing coil on antenna.

The two meter coils have more turns and are 6 inches long.

All of the fiberglass antennas like commercial types are wire antennas inside of a radome for support, and protection up on a high mountain top.
All commercial antennas used for repeaters are wire antennas hidden in the fiberglass radome, and are very visible to the eye.
 
The cost of the radomes is very high, as they need to withstand high wind and ice loads up on the mountain top.

My antenna design is not for a repeater in a high wind area or with ice loads. The antennas are NOT inside a radome!
The are for the average ham with trees or a tower, used for there antennas.
 
The commercial antennas are usually not more than 20 to 22 feet long because if used on a commercial tower they can not be more than about 22 feet above the light on the top of the tower. FAA regulations I believe.

When hanging an antenna from a large tree it can be any length under the tree limb used for the support. Thus a 10 element of my design is possible for two meters.
After about 15 elements the radiation pattern gets very flat.

My antennas are designed to have there maximum radiation at the horizon.
They can have down-tilt built in if ordered when placing the order. You must state this WHEN YOU ORDER.
Once the tilt is built in it can not be changed unless a new phasing coil is substituted.
By feeding the antenna with the J feed at the bottom, it uses a shorter coax thus, less feed line loss,  not at the center a folded dipole array like the commercial types that is up higher on the tower.

The phasing coils insure that the complete antenna array radiates at the horizon unless ordered with tilt.
The antenna weight is 3 pounds or less, this means a light rope will only be needed to hang this antenna.
Wind resistance is very low as the radiators are made from #12 stranded wire.
This collinear radiates all along the complete antenna array at the horizon.
The Two meter and Seventy Centimeter, 446 design, has the same radiation pattern, for each band at the horizon.

These are single band antennas, NOT dual band designs. Dual band antennas are a compromise design.

These antennas can be put up and taken down in less than 5 minutes as they are held up with a small diameter rope, say over a tree limb, or a yard arm on a tower.
Cost of my antennas are quite a bit lower as the radome is not needed.

Thus big savings, as no rotor or radome is needed for a NON DIRECTIONAL antenna.
They have the gain of a beam without the cost of a beam and rotor.

Questions you might have!

Question?

Can I put the antennas you offer inside PVC tubing for support so I can mount it on top of a mast and if I can mount it inside PVC tubing, will this change the swr readings? I don't have any way to support it from the top!

Answer--- Definitely  NOT !  This will change the complete frequency of the antenna.
This antenna was designed for light weight and stealth to be held up with a light rope from the top. And is pre tuned without a radome.

Question?
How far away from any metal surfaces does it have to be mounted? Example, like aluminum siding of a house or mobile home or other metallic surface.

Answer---About 12 inches from a tower and farther away from a house with aluminum siding or if it has aluminum backed insulation. I suggest hanging it from a  deciduous tree limb. Not a Pine tree, as they have a lot of moisture in them and also attract lightening.

Question?
Does the stated swr plots change when mounted higher than 3 feet above the ground?

Answer---No, but the bottom of the antenna will NOT handle the WEIGHT of extra coax. (
The matching J pole is made from 300 OHM Ladder line which is #18 or #20 in size. I am looking for ladder line made from #16 wire, but can not find any.)


Question? Are the swr plots on this web page done with the antenna at 3 feet above the ground?

Answer---Yes and No, also hanging from a tree limb with the MFJ 269 analyzer. The plots are generated with W7EL's 5.0 antenna program.
I also check each antenna as they are built, with the analyzer on my work bench inside of the shed and it is aluminum sided. Antennas are about 18 inches away from the siding when being tested. When hung with Dacron/nylon rope in a tree the VSWR does not change.

Question?
Can the 2 meter version of this antenna also "work" on the 440 band?

Answer---Yes, but the radiation angle and VSWR will be higher. I do not recommend this type of usage.

Question?
What type of coax should I use with these antennas?

Answer---52 OHM coax RG8X is a good choice if kept to short lengths of under about 15 feet total. Cheap coax is asking for trouble. I use 100% copper inner and outer braid coax with a clear jacket. At vhf and uhf, low loss 50 ohm coax is recommended like LMR-400.

I cut the coax pigtail 4 feet long but I advertise it as 3 feet on the antenna, since part of the coax is up inside the lower sleeve. The pl 259 is only soldered on the pin, the braid is connected by compression in the connector.

-------------------------------------

Leonard  WB3AYW

 


2 Meter band swr plot
Antennas built for 2 Meters are about 3 mHz wide  +_ 1.5 mHz
 with LOW VSWR under 2 to 1.


440 band swr plot

WARRANTY RETURNS....

No questions asked for 30 days replacement only if mounted at the bottom of the antenna less than three feet above the ground, or coax support at the bottom of the antenna.
Customer to pay all return shipping back to me.


ALL SHIPPING TO BE PAID BY CUSTOMER AND IS INCLUDED IN ANTENNA PRICE !

[ I reserve the right to make any modifications, or improvements in future designs and they will not be grandfathered into older designs. The model number might stay the same.
When you order, you will be getting the latest design at time of production!
]


INSTALLATION NOTES: 

Antennas must be mounted so the bottom does NOT exceed, 3 feet off of the ground! OR the coax feed line must be supported under the antenna. The antenna can not stand lots of weight at the bottom.

Installation on a tree limb----
do not pull the antenna up so it touches the limb! It must be hung under the limb, so as to not touch the limb, as this touching will detune the antenna. Remember to use support rope between top of antenna and the limb. Support bottom of antenna so antenna is vertical to the ground. Anchor the coax feed line at the bottom of the antenna using your own method to keep the antenna from moving. Avoid trip hazards with the feed line.

You do not need to take it down for bad weather as it is sealed for moisture. It has low wind resistance, and will sway in the wind some.
The bigger the design in elements the more you will notice this sway causing your S meter to vary some. But it will still work ok.

All antennas come with at least a 3 foot pigtail of RG 8X. These antennas come with a pl 259 on the coax pigtail. So a barrel connector is also needed (user supplied) for hook up to your coax. Seal these connectors well against rain.

Antenna will NOT withstand weight on the bottom section. All antennas shipped on Mondays.

Leonard  wb3ayw


HAM SPECIAL INTRODUCTORY PRICING!
(Prices will increase soon)
 

ORDERING DETAILS AND HOW TO ORDER.
(You do not need a PayPal account to order)
U.S. orders only. No out of country orders accepted...sorry!

ALL ANTENNAS ARE "HAND MADE" AND TESTED BEFORE SHIPPING!

2 METER VERSIONS
Model    AYW-14605 2 Meter 5 element 9.7 dBd J fed Collinear antenna 19 feet long  $89.00 shipped



Model    AYW-14610 2 Meter 10 element  13 dBd  J Fed Collinear antenna 35 feet long  $129.00 shipped


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


440 (70CM) VERSIONS
Model   AYW-44605 70cm 5 element
  9.7 dBd J fed Collinear antenna 6.5 feet long  $79.00 shipped

Model  
AYW-44610 70cm 10 element 13 dBd J Fed Collinear antenna  12.5 feet long  $119.00 shipped



All orders processed through Hamuniverse.com via our PayPal account only.
When ordering, Include your exact name, shipping address, including zip code and email address, and call sign if any.

U.S. orders only.
No antennas shipped outside the U.S.!

When we receive the notification from PayPal here at Hamuniverse.com that you have ordered, we will then transfer the order to WB3AYW to process and ship your order. Your order will be shipped as soon as possible BY WB3AYW.

The order will come from WB3AYW, not Hamuniverse.com. We are only acting as order prossessing at this time. 
You should receive a confirmation of the order via an email from WB3AYW as soon as possible after you place your order.

If you have questions about shipping, about the antennas, etc, contact WB3AYW directly at his email address ONLY.
 
wb3ayw@tds.net  Please do not email Hamuniverse.com about questions you may have. This will only delay your answer!
Leonard, WB3AYW will be happy to answer any questions!

NEVER INSTALL ANY ANTENNA UNDER, OVER OR NEAR POWER LINES FOR YOUR SAFETY!

About gain references used on this web page~

NOTE THAT ALL GAIN NUMBERS ARE LISTED AS dBd NOT dBi as others might use to make the gain seem higher!

If you wish to see the inflated gain numbers in dBi...just add 2.15 to these numbers! The higher dBi numbers look like your getting more gain don't they??? The reference antenna in all gain numbers is, the dipole = 0db gain. The dBi reference is an antenna in "free space" or single point reference radiating in all directions. Can you get your antenna in "free space" and get it to radiate equally in ALL directions including off the ends? Computer simulations can, but not in the real world of antennas.

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