"COMPACtenna" - fact or fiction?

Hmm, I think there might be something to this thing. Looking down at it from the top side of the antenna, it appears to be a form of small transmitting loop antenna with multiple loops. Looking at it from the side of the antenna, it appears to be a short vertical.

 

i put my 2/440 version through our courthouse security scanner. It is in a white plastic bowl. Not the greatest image. Not much guts to the antenna either but it work ok for its small size. On my car roof , center left side, it works as good and sometimes better than a Comet SBB5 that is trunk mounted

 

I forgot all about this thread until it was revived with another post today. Here is a link to the paper referenced in the article on metamaterial antennas you referred to above.
http://www2.engr.arizona.edu/~ziolk...ski_Peng_Z_antenna_measurements_AWPL_2009.pdf Notably their antenna has 30 dB better power output than a monopole of the same vertical size.

The metamaterials field is fascinating, basically controlling EM waves with numerous sub-wavelength structures to diffract the waves in desirable ways. That's very different than the Compactenna which is basically a variation of a spiral antenna per this patent https://patents.google.com/patent/US9407001

 

I finally had to change it out. I got tired of people flagging me down telling me I left something on my car!

 

I'll agree with that.

 

Wonder if this is similar to the beer can antennas popular with the 11m crowd? I see way more pick-em-up trucks with beer can antennas, and fewer Firestiks and whatnot nowadays.

 

I will volunteer to supply the materials, if someone wants to build one!

 

Mine works good.

 

I was curious about these antennas so I bought a tri-band 2m/220/440 version to test out. Using an HP/Agilent spectrum analyzer I tuned in lots of close and distant stations on 2m/220 and 440 using a peak search function and recorded the exact signal level then replaced the COMPACtenna with a full size tuned 1/4 wave antenna on the same vehicle, same antenna mount, same coax. The results were interesting and the COMPACtenna performed the same and up to 1dB better on 2m, My spectrum analyzer can easily read .1dB changes and there was a very slight difference depending on the direction I was receiving but on 2m this roughly 7in tall antenna is doing great.

On 220 it was a bit worse with signals ranging from 2dB down to 8dB down from a 1/4 wave on 220. On 440 signals ranged from +8dB to -12dB compared to a 1/4 wave and it was mostly dependent on the direction I was receiving the station from.

So the antenna is not a dummy load and it can consistently outperform a full size 1/4 wave on 2m. Not too shabby for its size. In the future I might test again from a hill top with an unobstructed view of all stations I receive to see if I still the major swings in level on 220 and 440 as I did in my driveway.

Besides being a hamster, I have professional experience testing antennas for pattern and gain as I was a range master at an antenna/RCS test facility for many years.

 

Interesting information....Thanks for going to the trouble to test and report.

As a-satellite guy,I wonder how this itty-bitty antenna would work receiving sats AO-91 and AO-92.