Folded dipole with crazy results

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mainetrunk

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May 29, 2011
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York county Me.
I made a folded dipole,
and what a surprise..
Now--the only number's and refference here is ;;
how many pics did I take of 1 at our Mt. Aggementicus,
and a fellow RR member telling me what it is..
After getting alot of 1/4 inch copper pipe,
I made huge loop's,
and other smaller size loop's.
Yeah--they were good for aviaition.
Then I got ahold of alot of 10 gauge bare copper wire.
I made loop's,
coil's, coil on a loop---THAT is where I started getting lucky..
So, i took some 1/8 inch copper tubing and started bending it.
This way, that way, made folded dipole where both sides of it was 2 inches apart.
Yes, the tubing was split....
Sheilding went on 1 side,
wire to the other.
So, after doing it 100 time's.
I threw on a coil to each end.
Well, many coils later,
I ended up with a WOW factor.
Bottom line; it was getting signal's 40 miles away, amoungst all the power -- wire's...
Well, I then tried to expand the distance from back to front..
Not widen the 2 ends from each other,
they stay 1--3/4 inches apart.. Period..
So, after molding this thing to a demented egg shape,
and still did coil after coil,
I got as good as it get's..
the tubing is about 40 inches long,
sepparated fairly well, side to side..
On both ends,
the coil/ wire starts flat for an inch,
then does a 1/2 inch loop to resume the direction before the loop.
1/2 inch later,
it hooks onto cable--shield, and wire.
i swear--it is burrying my FERRET for reception in most direction's in--ready?
It is kicking butt on uhf--450's, 470's, 480's,
vhf and a BIG surprise.
it is taking 800 and 900 mhz better than any antenna I got..
and I got some antenna's...hf-vhf-discone-condor-rubber ducks-800 mhz-RR, -
and a coil to snap on to any design I make, with uhf connection..
I am currently hearing Carrol county NH very well on it..
So, after the loop from the dipole, it goes to the cable;
and holding everything in place there is a 2 inch wide by 8 inch long 1/8 inch strip holding all connections in place.
Picture--you know when you make a fancy 0 and the sides are straight,
just curved on the ends?
Like that--with it cut--2 ends, 1 inch and 1/2 from each other.
I wish I did a video,
but i was in too much of a hurry to try it---ooops..
Isn't that crazy?
GREAT reception....
I also ,learned;
coil's do not have to be 50 wraps of wire.
But--1 wrap, incredible...
well-that's my luck..
i got another in mind--for HF.
8 feet of tubing waiting to be bent properly.
I'm thrilled...:] !!
 

QDP2012

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Feb 8, 2012
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Sounds interesting. When you can, please post a picture from your camera. I'm sure my imagination is not doing it justice.

Thanks,
 

wbswetnam

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DMR-istan
A little less than two years ago I made a folded dipole out of heavy copper wire. I used a 25" section of coax as a transmatch to get the impedance down close to 50 ohms (without the coax transmatch, it would be about 300 ohms). I have it outside now mounted on a 12' pole, and it is connected to my 2m rig for local repeater work. It gives me MUCH better operation than the ground plane antenna that I used to have my 2m rig connected to. The measurements are roughly 30" end-to-end and 2" across. It's not a professional job, no, but hey it works, and works well!

Here's a pic...

Since I took this photo, I reversed the loop outward so that it doesn't pass directly over the coax transmatch.
 

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prcguy

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So Cal - Richardson, TX - Tewksbury, MA
If you want to experiment a bit further you can run a wire from the point where the coax shield attaches to the antenna, straight across the 2" wide element and connect to the very center of the opposite side of the dipole.

This will make the bottom half of the dipole a simple fat grounded element and the top element will then be a folded grounded monopole. Its still a dipole but the feed point impedance will be closer to 50-70ohms and it will have more BW than a regular 1/2 wave dipole. You can then loose the coax matching section. This is the same type of element that DB Products, RFS, Sinclair and others use on their stacked dipole arrays.
prcguy

A little less than two years ago I made a folded dipole out of heavy copper wire. I used a 25" section of coax as a transmatch to get the impedance down close to 50 ohms (without the coax transmatch, it would be about 300 ohms). I have it outside now mounted on a 12' pole, and it is connected to my 2m rig for local repeater work. It gives me MUCH better operation than the ground plane antenna that I used to have my 2m rig connected to. The measurements are roughly 30" end-to-end and 2" across. It's not a professional job, no, but hey it works, and works well!

Here's a pic...

Since I took this photo, I reversed the loop outward so that it doesn't pass directly over the coax transmatch.
 

wbswetnam

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Oct 11, 2005
Messages
1,800
Location
DMR-istan
Thx, I appreciate the advice. As it is now, what I have works well, so "if it ain't broke, don't fix it". However, your suggestion gives me an excuse to make another folded dipole following your suggestion! For me the funnest part of being a ham is experimenting with antennas. With the exception of the ground plane antenna I have, all of my other VHF/UHF antennas are home-made.

BTW my HF antenna is also a folded dipole, but a LOT bigger - 65' end-to-end and 18" across, and 40' off the ground. I've made contacts all over Europe, S America, Caribbean, Asia and Africa with it. I love folded dipoles!
 
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mainetrunk

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Joined
May 29, 2011
Messages
1,564
Location
York county Me.
They are pretty easy to bend/create..
Nice job by the way!
My other 1 is about 3 feet tall and spread about 16 inches from side to side.
UNtested.
I was too busy making the 1st 1.
So--guy's please--
keep sharing your folded dipole's,
I love them!!!
I -gotta- get a tuner!!!!
2mhz---1200 mhz
 

majoco

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Dec 25, 2008
Messages
4,283
Location
New Zealand
Most older TV antennas here are folded dipoles as the driven element in a yagi. The centre of the long bit of the loop is at ground as the antenna itself is balanced - it requires a 300 to 75 ohm balun at the feed points or a phasing loop ( 180degrees x velocity factor ) to match the 75 ohm cable. I have just taken down a Band 2 folded dipole yagi at the lakeside cottage - I should have brought it home but it's too long to get in my wagon! It has one of those binocular baluns in a plastic box at the feed point.
 

mainetrunk

Member
Joined
May 29, 2011
Messages
1,564
Location
York county Me.
Tonight is the night i have been waiting for--reception wise.
This thing is going crazy with 800 mhz, analog-distance,
p25 trunk--distance
and--yes-- it is a directional antenna.
But it is kicking arse right now.
I am currently hearing Worcester county in Mass very well.
NO antenna i have had can get that reception.
unfortunately, that goes for my pride and joy too.
The FERRET..
rust in peace--discone, lol
 
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