Low 2m SW/High 70cm SWR

Discussion in 'General Technical Questions and Answers' started by KD6RAP, Jun 27, 2020.

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  1. KD6RAP

    KD6RAP Ham Member QRZ Page

    I was wondering if anyone could explain why I am getting really low SWR on 2m and high....like 7 swr, on 70cm. I have an icom 2730a hooked up to a arrow dual band jpole with an 18foot piece of LMR240. I am a new HAM and don't understand what I can do to try to fix the SWR on the 70cm side. Kind of afraid it might kill my radio.
     
  2. WA7ARK

    WA7ARK Ham Member QRZ Page

    Check the SWR every 5MHz from 429 to 449MHz. Make a table or graph and report back.
     
  3. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    What are you using to measure SWR?
     
  4. KD6RAP

    KD6RAP Ham Member QRZ Page

    I am using a Nissei RS40 SWR/Power meter
     
  5. WA4ILH

    WA4ILH Subscriber QRZ Page

    Did the UHF section of the antenna EVER work on 440 MHz or is this a new development? BTW, the ICom 2730 is a great radio. I have been running one in my Ford F-150 for several years now.
    Tom WA4ILH
     
  6. K8JD

    K8JD Ham Member QRZ Page

    Jaypoles are not my favorite antenna, may have to do with how you have it mounted. Even a simple 2 M GP will do better on 70 Cm. Maybe get a different antenna on loan from an aquaintance, and try that.
    Nearly ALL radios have SWR protection, where the power is cut low if there is over 3:1 SWR.

    Don't worry, but don't just leave things as they are.
    Have fun.
     
  7. KD6RAP

    KD6RAP Ham Member QRZ Page

    The 70cm portion of the radio works. Just the SWR is crazy high. From day 1 on that antenna. But 2m is good. I unthreaded the shortest element a bit and that seemed to help. Arrow is sending me a longer one for me to try to fine tune. My dad is getting a Comet GP-3.....so we'll see soon if its just the antenna. If it is Im gonna scrap it and get something similar.
     
  8. KD6RAP

    KD6RAP Ham Member QRZ Page

    Yes, I read that in the manual. Arrow is sending me a longer element. I get the lowest SWR on 450.....I think it's too short.
     

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