Strange looking ''Double J Pole''

[SOTS 87 7]

I came accross this on eBay, What are your thoughts?
Item no: 222167874642.

s-l160000.jpg

[teckniqs]

[Albert H]

That aerial looks like it's completely forked!

The maker twitters on about not using matching coils and then tries to extract another £50 for a balun to match to this effort. He uses the usual (bogus) "dBi" rating - even a dipole has 2.15 dBi "gain". He claims that it radiates omni-directionally - it might, but it's going to have some very interesting lobes in the pattern.

He wants £120 (+ another £50 so you can connect it). You can get more gain out of a pair of stacked dipoles with 75Ω TV coax phasing lines!

A simple, single ⅝ or ⅞-wave vertical with groundplanes and a matching coil will cost you about £20 in materials and outperform this monstrosity. They're also not obvious from ground level (they could be CB aerials).

Do yourself a favour if you want cheap, effective aerials and try the "Flowerpot" Antennas. They're easy to build and give good results.

[SOTS 87 7]

Precisely what I thought Albert, my first thoughts were not omnidirectional but very directional.
There is some total crap on eBay, the reason why I posted this. Agreed the only and most effecive way is a vertical.
I was passed one of those ''Dominator'' antennas a year or so ago, (looks like a cut down sigma 4). I believe it's a 3/4 wave, but yet to try it. From the write up they recon it can handle 1kw, it has an N socket so maybe. Only one way to find out.

[Frequent Lee]

Tried one. Absolutely shite. Poorly made too.
The owl yagi performs good but all the innov8 antennas are very very overpriced.

As Albert says, twin stack dipole will piss these out of the water.

[Albert H]

If you want a simple aerial with good performance that's cheap to make and easy to match, the J-pole is hard to beat. It's effectively a ½-wave, end-fed from a ¼-wave matching section. it's omni-directional, and you can build it from bits of plumbing material. If you want gain, look at the slot colinears (like the "6dB" aerial on Harry's Homebrew Homepage).

You're going to need a good SWR Bridge (at least) or an MFJ Antenna Analyser.