Would this work?????

[K0CMH]

You might try as long a piece of wire as you can string up, end fed with balanced feed line, and a big, healthy tuner.

[WB3BEL]

I am not sure why you are only considering horiz polarized antenna variants.

If you are short of room, the vertical antenna is a really good option.

If you want to work DX on the low bands then in my opinion, it's the best option for most folks.

It does not have to be a tower or aluminum tubing giant...If you have a tree you can support a vertical wire and use against a radial system. Its really easy and cheap to build so thats a plus for experimenters like yourself.

Good luck
Harry WB3BEL

[AD5ND]

Originally Posted by NC5S

I need/want an antenna for 80 meters. I don't have quite enough room.

So, here's what I'm thinking about building and wonder if it will work.

I need 134' of antenna and about 10 feet on both ends for cord and insulators to hang it. I have about 90 feet.

What if....

I wind 30 feet of wire, evenly spaced, around a piece of PVC pipe about 2 feet long, attach wire of approximate 19 feet to either side of the pipe. for 1/2 of the dipole and duplicate for the other side.

Will it work?

The overall length of wire would be the same as an 80 meter dipole. But, am I going to run into inductance issues with the wire wound around the PVC pipe?

TIA

Ed
NC5S

Yes you can add inductance to both legs of your dipole to make up for the fact your antenna is only 90' long. But you can't just wind the missing 30' on two inductors. The length of wire you need on the coils will depend on many things. Such as how big in diameter, how tight its wound, size and spacing of wire etc. Since your 90' of wire will show capacitance reactance on the 80 meter band you will need enough inductance to cancel it. Also your antenna will have a narrower band with than a full size 120'-130' antenna

[G7VQE]

Could you squeeze a Moxon antenna onto the plot.....rotating it might be a non starter but that would come in under the 90 feet and have gain hopefully in a useful direction.....there is a design on DX Zone with a reversible Moxon using two loops wired across the same supports.

Dave

[WA4OTD]

Yes, he has 90 feet in one direction, hopefully 67 feet in the other! I'm assuming you would string this up so 5 support structures.

Originally Posted by G3TXQ

That works, but ......

..... if you needed 134ft East-West for the linear dipole, you would need only 67ft E-W using the hex shape; however you would also need 67ft North-South to accomodate it!

73,
Steve G3TXQ

[KB9MZ]

You are getting as lot of bad information here! As long as each turn is canceled
by a contra wound turn then the wire length counts. Best to wind 1 or 2 wave lengths of wire with close wound ( pitch) turns as room is not a concern.
The Jasik antenna book shows a dipole made this way. It is like a slinky BUT one side is CW and the other side is CCW.The dipole can be bent to any shape as long as both sides are mirror images of each other, thus for this method room is not a factor any more. Ground plains are not necessary since you are dealing with wavelengths as opposed to fractional wave length radiators
A simplified wound dipole is shown in Jasik's book on Antennas but for simplicity reasons he has shown wide spacings on the turns probably by stretching to tune.
You can, of course, put the windings on top of each other and feed as a end fed vertical again no ground plain since it is not fractional wave length.
Have fun and play with it until it directs the way you want and also look at the basics of helical antennas.

[KB9MZ]

Thinking a bit more about your problem. If it were me I would get hold of some ladder line say 1 wavelength long. If you join both ends then you have your radiator which will be 300 ohms impedance, this you can match with a transformer ! As with all radiators make it longer than needed and then prune to suit. Before you prune. This style of radiator will allow any amount of deformation as long as each half of the radiator is a mirror image of the other half. In other words, any inductance added in erection , construction or deformation is canceled by the mirrored half. Using ladder or twin line allows you to do what you want with the length as one wire cancels inductance automatically by the other twin wire! Using pre made ladder line cuts out a lot of the DIY work and in fact you can just wind it one way on a plastic pipe and center or end feed it. As stated before no ground plain required whether verticle or horizontal which helps out if cramped for room.