Is this guy kidding ?

Discussion in 'Chat' started by K4TQF, Feb 23, 2015.

  1. K4TQF

    K4TQF Member

  2. W5HRO

    W5HRO Administrator

    That was posted way back in 2005 so I wonder what the outcome was?
     
  3. K4TQF

    K4TQF Member

    Here's his QRZed bio:

    Yes, this is the antenna you heard me on. It is my MRA (Minimal Reactance Antenna. I have the MRA in a typicaly cluttered back yard in Saint George, SC. I have obtained patent #7,084,835 issued August 1, 2006.
    It works quite well on 160m without radials. 14 countries, 40 states in 12hrs. However, radials improve its performance. It works fb on 80m. 160m: I am only using 12uH to match the antenna on 1.80 MHz to 50 ohms. The 2:1 VSWR bandwith is 60kHz. There are no resistors to broadband the antenna, only 10 turns of a 1/4" strap roller inductor. The 7/8" heliax is semi-buried all the way to the antenna.

    http://ken.crawley.org

    Ham since 1966 WN4ENE

    He further states: " Dear Top Band Friends, I?m not making any claims for my MRA beyond what I have either measured or worked. I try to avoid hype...

    The antenna pictured on qrz.com and my website has been in my back yard for 11 months. Impatiently, we all wait for testing under controlled conditions, which will happen in ?06 on the CA/Mexican border at El Centro NAF. This testing will be at AM broadcast frequencies for the same antenna, with a slightly higher mast and 16 tophat radials.. Transmitting at 530kHz makes Top Band a cakewalk. This is not for USA purposes however. EZNEC simulations were bogus, unbelievable. Lawrence Livermore Labs is sending me NEC 4.1 There is $4,000 worth of aluminum in the MRA as shown in the picture, -->
    machining extra ;) Quantity pricing of bulk aluminum will reduce that cost. Dave, AB7E is right, it is a vertical, but he may be incorrect about the MRA needing earth ground to work. I have one in Bahrain working on the roof of a 4 story building. I will be installing a RX only version for the USAF receiver site near Sacramento in 2 weeks?on a roof for SCOPE Command. If the new one works and the Bahrain one keeps working, then we need to see if the NEC 4.1 simulations show that the interaction of the cylinder (emitter grid) and the trampoline (collector grid) is sufficient for ground return.
    This working against its own ground plane rather than earth could well be the reason why it works. Ground losses are minimized. Of course, mobile rig BugCatcher antennas ?work? don?t they? Hmmm, I just worked MM0SJH on 1.848 and he gave me a 49. A SUV is similar in size to this antenna; but would it get thru on Top Band with a 24 foot whip?

    There are no radials connected to it, only an 8ft ground rod next to the tuner. The pads under the antenna have ½" thick plastic insulators, and the antenna rests on bricks. The LC tuner rests on bricks. The coax is buried. Network analyzer plots were largely unchanged when adding and removing 240 foot radial wires to the base. For you antenna experts: ok, it's a vertical, 24ft tall, with a 9 foot
    radial torus as the ground plane, and at this moment, 10 capacity wires 19ft each at 45 degrees.. To resonate the MRA on topband 1.850 I'm looking at 3100pF in shunt (on the antenna side) with 10uH in series on the John Bliss tuner.

    So, why mess with this type of antenna?? Some guys say all the antennas necessary have already been invented. I don't have room for a radial field. My pecan trees are too short. I like aluminum lawn sculpture. And I would like to make an antenna hams on high rise buildings or rocky mountaintops could use to get on Top Band. I would not be sad if I can prove that a capacity cylinder can add capacitance at the base of a monopole, in conjunction with a capacity hat, and eliminate the need for radials any longer than 3x the cylinder (think 50 ohms guys).

    If you take a look at the Gap Super C antenna you will see the beginning of a revolutionary idea. It is unfortunate that George died three years too soon. There are 3 things you can do to improve the Super C antenna if you have one. I have a federal patent applied (Dec04) for fundamental differences between the Super C and the MRA. A second patent will be applied for after the AM broadcast test, unless I decide to make the complete design details available to the Ham community.
    73, Ken ,WB4ENE "
     
  4. W5HRO

    W5HRO Administrator

    It's the surface area. It's probably the same thing as having a long enough length wire to match the frequency regardless of its configuration. If you have enough surface area using metal sheets of aluminum then it probably adds up to being the same thing in the end. The only issue would be that it's input impedance might be a bit unusual.

    Anyway, that's my guess...