Your Next POTA Antenna: The REZ Antenna Startup

Discussion in 'Amateur Radio News' started by W1DED, Oct 2, 2023.

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  1. W1DED

    W1DED Platinum Subscriber Platinum Subscriber QRZ Page

    When I first spoke to Mike Giannaccio W5REZ six months ago, he was at the very early stages of creating a new ham radio antenna company. REZ Antenna was more than just an idea but not much more than that. Mike was working hard on creating a quality production plan, he had built some prototypes and even sold those prototypes to a few lucky operators. From the beginning, it was clear that Mike was on a mission to create a successful and sustainable company. So, I wasn’t surprised to see an announcement recently that REZ Antenna had teamed up with DX Engineering to distribute his antennas. Mike already has several hundred antennas in the field and has plans to expand his product line. Watch this video interview to get Mike's update on REZ Antenna Systems and what the future holds. And, look for him in Dayton in 2024.
    KC6PCB, IK1NAP, K8NIV and 3 others like this.
  2. KD2GIY

    KD2GIY Ham Member QRZ Page

    I love me some good pota!
    W1DED likes this.
  3. N6SDK

    N6SDK Ham Member QRZ Page

    Another good interview Kevin, nice job. I recently purchased one of Mike's antennas; I can confirm the build quality is top notch. This antenna should outlast me. The power rating has been derated recently, however it's still much greater than what one would use while portable. I love Mike's entrepreneurial story. This is what American is all about. 73' cheers
    KC5JSR and W1DED like this.
  4. M6ECG

    M6ECG XML Subscriber QRZ Page

    Moonraker UK are the tops!
    AA3SO and W1DED like this.
  5. N4MU

    N4MU Ham Member QRZ Page

    Super Antenna MP-1 (an original, very well engineered and machined portable antenna) now back for sale on Amazon. I have used the MP-1 for several years on POTAs and it just works.
    KP4HE likes this.
  6. N1RBD

    N1RBD XML Subscriber QRZ Page

    $550? Is it made of gold?

    Regardless, no loaded coil can beat a resonant dipole.
    W3LES, KR3DX, AE0PL and 2 others like this.
  7. KL7KN

    KL7KN Ham Member QRZ Page

    I looked at the ads on DX Eng site, as the vendor site rejected my browser.

    For me, it looks like a lot of other, very similar products, the over $500 cost blew me away....and not in a good way. I’ll stick with my $20 Frisbee antenna, thank you.
    KR3DX likes this.
  8. K6STI

    K6STI Ham Member QRZ Page

    Use this program to calculate the Q of a coil with stainless steel wire. Then select annealed copper and see what happens to the Q.

    KR3DX likes this.
  9. W2GIW

    W2GIW Ham Member QRZ Page

    I activated Mackinac Island State Park on the 13th of last month with my KX2 at 5 watts and an AX1 for an antenna, on 20M.
    Good enough for me!!
    Ken, W2GIW
  10. VE3IPS

    VE3IPS Ham Member QRZ Page

    You get what you pay for and this is the best antenna for my use on 80m and 60m. It beats a MP-1 in the wspr test
  11. KN4XJ

    KN4XJ Premium Subscriber QRZ Page

    What's with the videos. I'm a You Tube Premium user and I don't select items I want to buy from a rambling, look at me video. Put some words on paper and maybe I'll look further.
    N5XF, KR3DX and AE0PL like this.
  12. K6STI

    K6STI Ham Member QRZ Page

    I ran some portable antenna and coil models for Mike, W5REZ. I used NEC-2 with the Sommerfeld-Norton ground model for average ground quality (permittivity 13, conductivity 5 mS/m) at 7.15 MHz.

    If you replace the stainless steel (SS) wire Mike's coil uses with annealed copper (Cu), coil Q rises from 71 to 497. When the antenna with four 33' radials is mounted 1" above ground (grass height), Cu improves the radiated signal just 0.9 dB. Ground losses overwhelm much of the improvement in coil Q. But if the antenna is mounted on a 30" picnic table (radials horizontal for modeling simplicity), SS gain improves 4.4 dB over SS at 1". This is like raising transmit power by a factor of 2.75. If you use Cu at 30", gain is 8.5 dB over SS at 1". This is a power factor of 7.1. Your marginal 5-watt QRP signal becomes a decent 35-watt signal.

    However, SWR is very high for Cu at 30" since the feed impedance is about 5 ohms. This is characteristic of an efficient, short vertical. I suggested to Mike that he add a second tuning collar to implement a shunt inductor across the feedpoint. This forms an L-network to raise the impedance to 50 ohms.

    Mike found that his current collar is so tight that it eventually will abrade tin plating on copper wire. The plating inhibits corrosion and is thin enough not to degrade Q. He needs to modify the collar anyway because it shorts adjacent coil turns. As an experiment, I tested a 40m Master Mobile coil at 5 MHz on my HP 4342A Q meter. Q was 640. When I shorted a center turn, Q dropped to 150.

    Eight radials instead of four for SS at 1" improved gain 1.9 dB. Not bad for some extra wire on the grass.

    The following plots show why personally I would avoid a short vertical on 40m. They compare the SS antenna at 1" with an inverted V at 10 feet and at 15 feet. The ends of each V were about 1.5' above ground. The vertical is a little better at very low angles, but either V blows it away everywhere else. I think erecting a lightweight short mast is easy just about anywhere. And if there is a tree limb nearby, you may be able to get it even higher without much trouble. The V occupies the same space as two of the vertical's radials.


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    Last edited: Oct 14, 2023
    K2LED and KR3DX like this.
  13. K6STI

    K6STI Ham Member QRZ Page

    1.png 2.png

    I forgot that inverted Vs radiate well at low angles off the ends. The previous plots showed the response broadside to the Vs. These plots are at 90 degrees. Off the ends both Vs beat the vertical at all elevation angles.

    K2LED and KR3DX like this.

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