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Cushcraft ar-10 problems

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by W3TEZ, Nov 25, 2019.

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  1. W3TEZ

    W3TEZ Ham Member QRZ Page

    Just acquired a new ar-10 to replace an old imax 2000 with cracking fiberglass...

    Put the antenna together per the instructions and the illustrations. And set the antenna to length and measured it out to mid band at 192” like the instructions say. Got the ring section all assembled like the drawing resembles. Have brand new coax cable on it ends installed properly no shorts no impedance issues and has been tested on my dummy load.

    the swr on all of 10 meters is well over a 5:1 swr. The lowest swr I’ve seen on this antenna has been a 1.3 on 29.600 and a 1.1 on 30.300mhz. These best swr readings are if the antenna is fully extended beyond the manufacturer specifications where you cannot go any longer. I’ve owned a lot of antennas in my time and never seen anything like this where I’m completely flabbergasted. I contacted the manufacturer with not much luck and I had multiple people locally look at this antenna and cannot figure out the issue. The readings are on my brand new antenna analyzer I refuse to install the antenna up at at full height and take it back down adjust put back up and do the same process 20 times and get nowhere. I had the antenna 8’ off the ground in a clear spot and cannot get an usable swr on 10 meters.
     

    Attached Files:

  2. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    You do realize the SWR adjustment isn't the radiator length, it's the sliding tap on the ring, right?
     
    WR2E likes this.
  3. N3PM

    N3PM Ham Member QRZ Page

  4. W3TEZ

    W3TEZ Ham Member QRZ Page

    Yes, and even that didn’t do much at all
     
  5. W3TEZ

    W3TEZ Ham Member QRZ Page

    I wonder if making homemade wire radials the same length as the driven element would help even though the antenna will be elevated but tie the homemade radials off into the tree and other non conductive areas
     
  6. W3TEZ

    W3TEZ Ham Member QRZ Page

    I was searching through google images and seen a pic of an ar-6 antenna where someone did that wondering if that will help
     
  7. W3TEZ

    W3TEZ Ham Member QRZ Page

    I tried moving the sliding rod in the matching network didn’t do much
     
  8. WG8Z

    WG8Z Ham Member QRZ Page

    I was given an ar-10 about 13 years ago. The guy who gave it to me bought it new but never could get it to tune.
    Problem was something amiss in the coax stub capacitor. I can't remember exactly (long time ago).
    Either cold solder on connector pin or shield short.
     
    NH7RO likes this.
  9. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Yes, that could be an issue.

    If the coax stub isn't connected well, or is the wrong length, or the far end isn't "open" as it should be, the antenna won't tune.

    If the tuning rod (tap point on the ring) "doesn't do much," that's very weird. I've tuned lots of AR-10s over the years and found that to be a pretty critical adjustment, where the SWR "dip" occurs at exactly one tap location, and moving the rod around the ring by even 1/2" in either direction was way worse. If it's not making any difference, sounds like something isn't connected.
     
    WA7PRC and NH7RO like this.
  10. AA5MT

    AA5MT Ham Member QRZ Page

    I see that you have 1:1 at some frequency. Does it change when you change the height? If it doesn't, something is way off. The total height sets the frequency, the stub does a rough swr correction at that frequency, and the tuning rod does fine swr adjustments at that frequency.

    I have an AR-6, which is identical except for the height and stub length.

    Tom
     
    NH7RO likes this.

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