Zero-Five elevated 29ft multiband vertical

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by W2KS, Nov 3, 2012.

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  1. W2KS

    W2KS Ham Member QRZ Page

    I just purchased one of theses antennas after my Cushcraft R-6000 was twisted into shambles by Sandy. The installation will be as such:
    The antenna will be elevated on a 10 ft 1 5/8 pipe ten feet off the ground (the ten foot pipe is bolted to a metal post cemented in the ground from an old chain link fence, which is right next to my shed (wood). Only the post remains (the chain link is long gone). The antenna will be grounded to an 8 foot copper grounding rod using #8 copper wire. So the top of the antenna will have a height of 39 ft. The base of the antenna would be just above the roof height of the shed (10 ft).
    My questions are these:
    1) Can I use the counterpoise from the R-6000 as an effective counterpoise for the Zero-Five if I place it at the base or feed point of the antenna. The total length of all the counterpoise radials (7 at 4' each) is 28 ft. I can add another foot to equal the height of the antenna.
    or,
    2) If I were to put radials at the base of the antenna (the feed point 10 ft above the ground), how many should I need, and how far off the ground should they be?. I have limited space, and the radials would not be semetrical in their spacing due to logistics of my property (A shed, which is next to a deck, which has a 6 foot stockade fence behind it.
    or,
    3) Just throw the darn thing up, connect it to a tuner, and see what happens. Thanks, Ken W2KS
     
  2. KH6AQ

    KH6AQ Ham Member QRZ Page

    From the Zero-Five manual:

    1) Mounted on a 10' pipe the radials should be 30' long. The R-6000 counterpoise will not work.

    2) Two to four radials are recommended.

    I think that two radials running opposite one another would be better than four radials non-symmetrically placed. If not configured symmetrically the radials will radiate.

    It is best to elevate the ends of the radials rather than to slope them to the ground. Ground losses will increase as the radials get close to the ground.

    An alternative is to ground mount the antenna. I would use 30 radials 20' long.
     
  3. N0AZZ

    N0AZZ Ham Member QRZ Page

    The Zero-Five will make you a very fine dummy load if it were me I would find a better vertical there are many superior choices out there. JMHO from trying one for several weeks.
     
  4. K4SAV

    K4SAV Ham Member QRZ Page

    Wow, that must be some fantastic matching transformer in that vertical. It's supposed to make the antenna super broad banded, 80 meters thru 6 meters, handles 1.5 KW continuous, all with a 29 ft vertical with or without radials. Implied is an SWR of less than 3 to 1 at the station end of the coax when used with 50 ft of RG213.

    I was curious as to what his antenna looked like on 80 meters so I made a model (ignoring the effects of the amazing matching transformer and replacing it with an ideal 4 to 1 current mode balun) and it produced a curious result. I used four 29 ft radials (as suggested by Zerofive) with the base of the antenna at 10 ft, and one ground rod. It produced a relatively low SWR at 4 MHz! Moving the base of the antenna to 15 ft, the low SWR point moved to 3.5 MHz. (This was a low SWR point relative to 50 ohms, but not a resonant point.) The current into the ground wire was about 2.5 times the current into the top part of the antenna. Most of the radiation on 80 meters (which was pretty low) was from the wire between the base of the antenna and the ground rod.

    Antenna base height also had a significant effect on the other bands. I suspect that is because the 29 ft radials don't do much on some bands.

    Jerry, K4SAV
     
  5. W5DXP

    W5DXP Ham Member QRZ Page

    Conductive mounts sometimes have considerable effects on certain antennas and they are usually negative effects.
     
  6. W9GB

    W9GB Ham Member QRZ Page

    Ken -

    Glad you are OK, I still have not heard from friends in New Jersey -- they are in the Electric outage area.

    Sorry to hear about your Cushcraft R-6000 vertical.
    Your black matching box (MN-6000) and traps should be OK,
    I would be happy to pick-up the salvageable pieces.

    You can NOT use the 48 inch counterpoise wires from R-6000, they are too short.

    Here is the Installation instructions for your Zero-Five:
    http://www.zerofive-antennas.com/sites/default/files/BROADBAND_VERTICALS_0.pdf

    Elevated mast
    You can mount your broadband vertical higher for better performance if you follow these important tips. When mounting on a mast 8 to 10 feet high, you have to use elevated radial wires attached to the base tube of the antenna.
    The radials have to be the same height off the ground as the antenna base, this serves to raise the effective ground under the antenna for best performance.
    You can use 2 or 4 radials the same length as the height of the vertical. Example: if you have the 24 footer you will use 2 or 4 radials 24 foot each.

    14 AWG wire would be easiest to install for these radials, 100 foot rolls at local hardware stores.

    ==
    w9gb
     
    Last edited: Nov 3, 2012
  7. K4SAV

    K4SAV Ham Member QRZ Page

    You could isolate the vertical by removing the ground connection but that may not solve much. When you do that, the SWR that the coax sees on 80 meters goes very high and coax loss increases by a very large number. With 50 ft of coax, the gain probably won't change much. If you have a longer coax the gain may go down. Of course that assumes the matching transformer looks like a 4 to 1, and it might not. There have been other transformers designed that radically change their characteristics with frequency, and I have no information on this one, so it's unknown if removing the ground connection will help or not.

    Jerry, K4SAV
     
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