1/4 wave dipole.

[Tyrol]

Has anyone used a 1/4 wave wire dipole? Is it worth trying?
Would like to hear any stories that you might have.
I have very little room, so it has to be small and discrete(hence the 1/4 wave). The old people next door had a fit when I put up a 2 meter beam and I would like to keep them as happy as poss.

Regards,
Tyrol.

 

[W5LZ]

Tyrol,
I'm afraid it won't work worth a hoot if it's to be used for transmitting. If each 'side' to that dipole is 1/4 wave long, making the total length 1/2 wave, it'll work just dandy.
I think you'll find that a single 1/4 wave element, no 'other half' of it anywhere (making the total length 1/2 wave) won't work, because it isn't even close to 50 ohms input impedance, and certainly not resonant.
You could 'load' each side of a dipole making it electrically 'longer', and wind up with a total length of around 1/4 wave length, but that's not exactly easy to do from 'scratch'. Certainly possible though. Performance is also reduced a lot. You have the equivalent of a 'rubber duck' antenna like on a hand held.
Good luck.
- 'Doc

If this is for 2 meters, there are several 'shapes' of 'stealth' antennas that might be handy. One looks like a plumbing vent pipe for roof mounting. Never used one so can't say anything about how well it works. Gotta be better than nothing though.

 

[1342]

Has anyone used a 1/4 wave wire dipole? Is it worth trying?
Would like to hear any stories that you might have.
I have very little room, so it has to be small and discrete(hence the 1/4 wave). The old people next door had a fit when I put up a 2 meter beam and I would like to keep them as happy as poss.

Regards,
Tyrol.

after my imax snapped i hung this one with a piece of bamboo and my 20 foot mast.worked as good if not better than my antron i had up there before.

 

[Beetle]

If you try to use a half-wave dipole for 40 meters on 80 meters, for example, you're doing exactly the same thing: using a quarter-wave dipole.

Generations of hams have tried it. If they used coax as a feedline, the results were pretty uniformly dismal. Maybe a few local contacts but very little DX.

A quarter-wave dipole (which by definition would be center-fed) has a very high feedpoint impedance. Even with a matching network, feedline losses will be pretty high. Using parallel feeders and a matching network might normalize things. The same would hold true for using that 40 meter dipole on 20 meters. There, it would be a one-wavelength, center fed antenna. Also with a very high feedpoint impedance and the attendant problems.

But a full-size half-wave dipole for 11 meters is less than 20 feet long, and will perform rings around any shorter dipole wannabees.

 

[Tyrol]

So half wave it is then. Thank you all for your input. Looks like this will go under the eves of the house to keep everyone happy.

Regards,
Tyrol.

 

[1342]

if you could get that thing in a tree you would be one happy camper!

 

[Tyrol]

if you could get that thing in a tree you would be one happy camper!

Sorry, I've got nothing around but a couple of shubs. Hope to be moving soon so I may have more options in the near future.

I got it up today, still trying to tune it, will let you know how I get on.

 

[W5LZ]

And the other thingy about antennas (any of them) is that they do much better if they are not near things, such as the eaves of your house. That 'under the eaves' antenna will work, but will probably not be that easy to 'tune', and certainly will not work as well as if it were away from that house.
Which does NOT mean that you shouldn't try it! I don't care how 'bad' the performance is, it has to be better than nothing, right?
- 'Doc

 

[packrat]

Put it at the peak of your roof, tuck it under the shingles in a few places to hold it in place. Still invisible, but you gain 8 feet or so, and dont have to drill any holes in the eaves.

 

[Beetle]

Put it at the peak of your roof, tuck it under the shingles in a few places to hold it in place. Still invisible, but you gain 8 feet or so, and dont have to drill any holes in the eaves.

Might not be a good idea. The ends of a dipole are high-voltage points, and even with ~100 watts are easily able to set fire to flammable material near them. Not from thermal energy but due to the RF field. End insulators are there for a reason.

 

[Tyrol]

Just an update, ended up hanging it from my gable, the feedpoint is right by a window so I get it perpendicular for a good 1/4 wave, seems to work good.
SWR could come down a bit, but i'm happy and the neighbours haven't said anything.

Thank you for all of your replies.