Saw this on fleabay for about $9.  Figured what the hell, it's cheap, I'll give it a shot.  Using it on a tripod with a small ground plane kit in the computer room, and the SWR seems pretty decent.  1.2 at 146 and 1.8 at 448.  Though... it doesn't seem to work as well as the stock HT antenna on a few different radios getting into a local 2m repeater (about 4 miles away).  Has anyone seen this design used by a reputable manufacturer?

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That is a strange looking antenna.

It's a folded/linear loaded antenna that you more commonly see for HF antennas to reduce the size.

It appears to only have UHF size ground radials which will impact the performance on 2m/VHF in addition to the loss from the linear loading.

This.

Avanti called and wants their Astro Plane CB antenna back.

Damn, I thought I had seen something like this before. Thanks.

Yeah the ground radials are the "vhf" size that come with the Nagoya kit. Kinda short. I need to find something to replace
them with.

Do those radials screw in? If so just add extensions on the end of those radials with stiff wire attached to small alligator clips

If they are held in by a screw, use sized welding rods or wire coat hangers.

Yeah, they're threaded in.  I was going to buy some stainless wire rods, they seem to be pretty affordable on amazon in packs of 10, 20, 30, etc.  I do have some aluminum tubes that can slide over those, they re a bit loose, and I'd have to probably slot the end of them and use zip ties to hold them on.  Might work, too.  

Or, just get some of those Tram GPKs, with the right length radials already.  

I'm also using a short run of RG-8X to the radio, which is almost directly underneath the antenna, maybe 4-5' long.

Oh, and the antenna is grounded to the aluminum tripod that it's mounted to, so that might act as as sorta-counterpoise, too.

Don't forget that metal can be "staked" together also. As long as there is not too much "slop" in the fit you can stake metal together like this with an automatic center punch. You can use a regular center punch and a hammer, but it is more difficult to keep things still and hit the punch with the hammer. With the spring loaded automatic center punch it only requires one hand to operate and the "hit strength" is easily adjustable and repeatable.. Metal especially aluminum or thin steel can be staked very easily and will hold very well.  Automatic center punches are usually less than $10.  Amazon, Harbor freight, etc.