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full wave 10m antenna, will this work?

S

ShadowecR

Member
Oct 18, 2009
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ok, any ideas whether this will work or not?

I have two 9' fiberglass poles that have mounts (normally used as flag maker polls on off road trucks).

If I start from the base using winding coil wire (unsure what gage to use??) and run it straight up the side to the end of the poll. Than turn around and run it back down to the base. (now I'm up to 1/2 wave?) now repeat for the two remaining "sides" or quarters of the poll. Have I now reaches full wave? I would than finish it in the standard way, leaving a way to tune it. Does this sound like it has possibility?

Also, if one would work at full wave, would constructing two polls of this sort and putting them in phase be better or would that not work as it is already at full wave?

Thoughts, ideas??? Thanks everyone
 

I have no idea what you would have other than an antenna that would not work,especially as a full wave antenna. The four lengths of wire would be so close the coupling would be an issue and the radiation fields of each would cancel out because of them being out of phase with each other. You would be better off using either a single wire or use four wires all connected together at the bottom and open at the top and fed directly. That will keep everything in phase in the four wires and will increase the bandwidth over a single wire.
 
its my understanding that if you use something shorter than a 1/4 wave youll need to use a coil to to get it to tune . if you go longer than a 1/4 wave youll need to use some sort of matching system (coil or ring) for tuning . and of course youll need some sort of ground element(s) . i use pvc pipe for my radiator support on my homebrew 1/4wgp and just taped the wire (12 gauge stranded copper) up the side of it and clipped the wire to tune the antenna . i also used pvc to make a X to hang below the feedpoint to spread out four 1/4 wl ground radials .

BELOWANTENNA.jpg


WHOLEANTENNA.jpg


i used 3/4 scheduel 40 pvc pipe and while its done fine for the ground wire x it is not able to stay verticle over time in my use with it . i think one inch might but your fiberglass rod shouldnt have that problem . ive been told that pvc will eventually breakdown or crack/break being exposed to sun and weather like it is , but that wasnt a problem because it was built mostly to see if i could build one and then try something better later . its still talking after several months though .

if you decide to do something more permament DX engineering has aluminium tubing and other antenna parts and are VERY fast at shipping .
Aluminum Tubing Type 6063 - 6 ft.
 
I can see where you are trying to 'go' with this but I'm afraid is just doesn't work that way. 'Up and down' all four sides of that pole to get 1 full wave length of wire on it won't work because that wire needs to be n a particular 'shape' to work as an antenna. As each section going up/down makes that turn, it in effect cancels-out the preceding section of wire (that's not actually how it happens, but it's close enough to give you the general idea. Change that "cancels-out" to "messes with" and it'd probably be closer to what actually happens.). Just because that wire happens to be a full wave length on some specific frequency, the resulting antenna won't be resonant near that specific frequency.
BUT! there are antennas that are similar to that but change one of those dimensions and works well. Be da##ed if I can remember the name of the thing bu instead of using opposite sides of a pole, those 'side wires' are much further apart. Sort of make a loop in one direction and then another loop 90 degrees 'around' a center point. How'z that cor a crappy way of describing something you can't remember the name of?? the examples I've seen of those thingys are about twice as 'tall' as they are 'wide'. [that's gonna bother me till I either look the thing up of remember the @#$ name. RATS!]
- 'Doc
 
also a full wave antenna will shoot a lot of your signal straight up reducing your local and longrange distance .
 
Careful Booty', that's not exactly true. Those high angles of radiation do rather well at close range, and do not affect the longer range stuff all that much. Don't 'poo-poo' those full wave loops too much, they really do work. Sometimes not too well, but you can say that about any antenna. :)
- 'doc
 
I like loops! Big ones! Used an 80 meter loop on all bands, did well enough except for
15 meters, it didn't like that too well. A horizontal one can be either vert or horiz polarized,
just depends on where you feed it. You know how it goes, doesn't work the same for every
situation, but I've done just as good with that loop as I have a dipole of verticals. Some
people like chocolate, I like strawberry. Whoopy.
- 'Doc
 
picture worth a 1000 words

Thanks for all the ideas and insight so far. From what I'm hearing this idea might/would sort of cancel itself out. Does everyone else concur? I sent a photo to clear up any confusion of the design idea. Thanks again for all the help.

fullwave.png
 

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I've gathered some things together to make it but if this kind of design is known not to work, i'd rather try something else. :) any other thoughts before I start? Thanks again everyone.
 
Full Wave Loop, One Half Wave Tall

I built one many centuries ago and had to feed it at the side-center with 75ohm RG-11 cut to 1/4 wave length multiplied by the velocity factor, which in this case was 66% so it ended up ~5' 7" long (for 28.4mHz centering) and which matched it to the 50ohm coax nicely.

It was a good performing antenna but a bit challenging to get the feedline to attach from perpendicular to the antenna.

I kept the inherent potential impedance at a factor of 10+ above 50ohms by separating the wire 1.5 inches as it traveled up & back down the outside of the 20' x 1.5" fiberglass rod.

Handled full legal power @ 1.2:1 vswr until a falling tree branch had it for lunch.

Let us know the outcome.
 

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