Zero 5 Vertical not loading on 160 or 80 .

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by W1TXX, Mar 6, 2020.

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  1. W1TXX

    W1TXX Ham Member QRZ Page

    My Zero 5 antenna will not load on 160 0r 80.
    Radio-Yaesu FT-450D
    Tuner MFJ -994B
    Antenna Zero 5

    Antenna has worked great for more than 3 years.
    All bands fine into dummy load in shack. Installed dummy load out at antenna. Everything there ok also.
    Also have Ameritron ALS-600, but not part of problem.
    I can't think of anything that could effect frequency of a vertical antenna on 2 lower bands only.
     
  2. WD4ELG

    WD4ELG Ham Member QRZ Page

    Are you saying that the antenna tuned on 160 and 80 in the past, correct?

    Which model antenna, what length? When you say "won't tune" what behavior are you observing?

    Tell us about the radials you have for the thing.

    Have you tried using the tuner in the rig? Have you tried checking the coax for integrity/breaks?

    What about the connection from coax to antenna? What about the interconnections between the aluminum sections?

    Just spitballing here, please share some details so we can help.
     
  3. W1TXX

    W1TXX Ham Member QRZ Page

    Thanks for reply. Antenna did tune fine. Zero5 is 43 foot with matching transformer. Have (40), 43 ft radials. Rig tuner not working either. I even removed transformer which almost never fail.
    Regards Darrell
     
  4. KH6AQ

    KH6AQ Ham Member QRZ Page

    It sounds like problem is either the MFJ-994B or the 43' vertical.

    Original
    TX---->ATU---->COAX---->XFMR---->ANT

    Sans transformer
    TX---->ATU---->COAX---->ANT

    1) The TX drives the dummy load in place of the antenna, so it's not the TX.

    2) The SWR is correct with the dummy load in place of the antenna, so it's not the coax.

    3) The antenna works on 40-10 meters, so it could be the antenna if corrosion has disconnected one of the upper sections. Separating the sections and cleaning the connecting areas will solve the problem or leave the MFJ-994B as the problem component.

    4) The MFJ-994B should tune the 43' vertical on 80 meters without the transformer but it doesn't, so this points to the tuner or the antenna.
     
    Last edited: Mar 7, 2020
    WB5YUZ likes this.
  5. K8JD

    K8JD Ham Member QRZ Page

    U have a vertical that is basically a QW for 5 MHz, (234/43=5.44 mHz) SO, you need more inductance in siries with the feedpoint to get it down to 3.5 and 1.8 MHz, some L for 3.5 and twice that for 1.8 mHz.
    If that fails you have to fix it.
    Did you check the radial field under the vertical ? that has a big effect.
     
  6. K1LKP

    K1LKP Platinum Subscriber Platinum Subscriber QRZ Page

    DARRELL,

    EVERYONE HAS PROVIDED YOU WITH TOP NOTCH SUGGESTIONS.

    BESIDES THE ABOVE INFO,,,,,,,,,,

    YOU SHOULD TAKE DOWN THE ANTENNA AND GIVE IT A THOROUGH
    INSPECTION.

    THEN PROCEED TO THIS SITE FOR SOME GREAT INFO REGARDING
    THE VARIOUS COMPOUNDS TO USE ON YOUR ANTENNA JOINTS.

    CHIP PROVIDES SOME GREAT INFO AND BE SURE TO READ THE
    ENTIRE SITE.

    https://www.seapac.org/seminars/2017/SEA-PAC2017-k7ja-building-antennas-that-last.pdf

    HAVE FUN AND WORK SAFELY.

    73 - K1LKP
     
  7. AF4RK

    AF4RK Ham Member QRZ Page

    I had a 43' antenna with a Balun Designs Un Un (so called matching transformer). he says he has an amp, so most likely he fried the matching inductive device, whatever it is. Not much to go wrong with a 43' piece of wire. And he will never tune 43' on 80 or 160 without a loading coil. I gave up and wound a custom base loading coil and that worked ok. Impressive radials, funny about the 43' that is 5 mhz but i guess length is not critical. I had a harris RF 103 with a 3-1000Z. Weighed 250 pounds. The leads to the 43' vertical melted and shorted and all I heard in the shack was a brief humming sound. I went outside to the pvc box at the base of the vertical and it looked like a hand grenade went off. those transformers get really hot with power because the impedance of the antenna is so far away from anything in the ham bands. I went out to the antenna and found the Un Un was smoking! It didn't like 15 meters at all. But it didn't fail. I found 40 and 20 worked the best. 15 and 10 not at all and 80 was poor without a base loading coil. Life is to short for QRP and it's definitely too short for 160 m without a decent antenna. That band is a mess. Only serious minded engineers even attempt to make anything work on that band. unless you have acres of real estate avoid that band and even then it's a challenge. 40 and up will work without the transformer. Best advice, get one of those Hustler trap verticals like the 5BTV, with those radials you will definitely get out. And be realistic, 160 meters is for people who either are engineers or could be if they wanted to. Tom Rauch, W8JI, has some good material on 160m antennas as well as Rudy N6LF. I am a contester, so when I say an antenna works or doesn't work, it means I had decent rate (QSO's per hour) or I didn't . you can't fake it in a contest.

    af4rk
     
    N1VAU and WD4ELG like this.
  8. W1TXX

    W1TXX Ham Member QRZ Page

     
  9. W1TXX

    W1TXX Ham Member QRZ Page

    Carmen, thanks for your reply. We ,my wife and I, have been away for 5 days, hence the delay in reply.I think your suggestion re take down antenna and check connections will be my next step. I am 87 so I have to plan things well ahead.
    I will reply to all others when I can .
    Regards Darrell
     
  10. W1TXX

    W1TXX Ham Member QRZ Page

     

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