"COMPACtenna" - fact or fiction?

Discussion in 'VHF/UHF - 50Mhz and Beyond' started by KK6QMS, May 27, 2017.

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  1. K1ZH

    K1ZH Ham Member QRZ Page


    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.
     
  2. K8SWD

    K8SWD Ham Member QRZ Page

    3B19C3FC-394A-49A0-BCD5-EC7C43F8F7FC.jpeg 3B19C3FC-394A-49A0-BCD5-EC7C43F8F7FC.jpeg 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
     
  3. N0TZU

    N0TZU Platinum Subscriber Platinum Subscriber QRZ Page

    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
     
    Last edited: Dec 23, 2019
  4. WX1FLY

    WX1FLY Platinum Subscriber Platinum Subscriber QRZ Page

    I finally had to change it out. I got tired of people flagging me down telling me I left something on my car!
     
  5. KC1DR

    KC1DR Subscriber QRZ Page

    I'll agree with that.
     
  6. KF5FEI

    KF5FEI Ham Member QRZ Page

    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.
     
  7. KC1DR

    KC1DR Subscriber QRZ Page

    I will volunteer to supply the materials, if someone wants to build one!
     
  8. KC1DR

    KC1DR Subscriber QRZ Page

    Mine works good.
     
  9. KM6AB

    KM6AB Ham Member QRZ Page

    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.
     
    KC1DR likes this.
  10. K4BAD

    K4BAD Ham Member QRZ Page

    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.
     

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