super antenna mp-1

Discussion in 'Becoming an Amateur Radio Operator/Upgrading Privi' started by KF7AJU, Mar 11, 2010.

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  1. KF7AJU

    KF7AJU Ham Member QRZ Page

    I am new to HF and am trying to tune an MP-1 for 10 meters. I am using RG8 with a 7ish coils wound for a simple choke. (only because it is there for a dipole I also built). My swr's are way high. Lowest I can get is 5:0. If I set up the antenna per the instructions for coil and whip settings it is not even close. I need to shorten it way down to reduce swr at all. I built new radials out of network cable at 8.75 ft for the 10 meter band and that did not help. I tried mounting it to a grill, a metal picknik table, a tripod raised up high, all have high swr on my analyzer. The only thing I have not tried is mounting it to a non conductive pole at height. I live in a very tight backyard patio home. Could the house be the problem?

    Any ideas?
     
  2. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    The house be the problem?

    I'd say "probably not."

    This is an extremely narrowband antenna with very critical tuning.

    Since you seem to have an analyzer, try this:

    Attach the analyzer where you can see its meters and stand next to the MP-1.

    Loosely grab the MP-1 with your hand and run your hand up its length from the base to the tip and see how the meters react.

    If no reaction, the antenna's not even connected.

    Then, try grabbing the coax (loosely so you can slide your hand) just at the antenna and running your hand along the coax back towards the analyzer (away from the antenna). Does that affect the meter readings? What happens?

    Hate to say it, but I found the MP-1 (have one hanging in my garage rafters right now) to be a pretty poor excuse for an antenna. Almost anything I've tried "portable," including tossing a random wire over a tree limb, works better. But some people do get them to work.

    If ten meters is your main concern, I'd put the MP-1 aside, get a cheap CB mag mount, stick that to anything that large, horizontal and made of magnetic metal, and use that. Almost guaranteed to work better and have no tuning issues.
     
  3. KF7AJU

    KF7AJU Ham Member QRZ Page

    Thanks for the reply. I intend to use other bands for portable work but only have a tech license now. Therefore I was playing with 10 meters as a start with this new antenna. I spoke to Vern today at super antenna (very helpful fellow) and believe the problem was I didn't have it short enough for 10 meters and I didn't search for where it was actually resonating. He also suggested trying a different length coax to see if that made any difference.

    I'll play with it again this evening.
     
  4. KF7AJU

    KF7AJU Ham Member QRZ Page

    I have this antenna figured out after working with it a bit more. I did get nice swr readings and will mark the antenna for quicker tuning in the future. Switching to better ground poise wires dropped it a tad more. I could get 1:5 without to much trouble. I listened to Hawaii and Illinois from Arizona in the few minutes I had to play with it on 40 this evening. 10 was dead. This is going to be fun! I need my general!
     
  5. W3CUM

    W3CUM Ham Member QRZ Page

    I had a mp1 untill it met an untimely demise during a snow storm... the best thing you can do is get A LOT of counterpoises out. the longer the better. I used to put out 10 25 ft wires... it really helped in the tuning. I was able to work Germany and Italy on 25w from Washington DC on 40m....
     
  6. K7ZME

    K7ZME Ham Member QRZ Page

    MP-1

    I have the same antenna. The counterpoise is designed for 15 meters through
    20 meters.

    #1. shorten the ant by 1-2 feet for 10 meters.
    #2. reduced the length of the counterpoise by 2-3 feet.
    #3. check and make sure you have no shorts in your coax.
    1/4 wave for 10 meters is about 8 feet. not much room for tunning!
    Good Luck,

    73 de KC6ZME

    John
     
  7. NU4L

    NU4L Ham Member QRZ Page

    Mount for MP1?

    Do you by any chance have the multi-adjustment aluminum clamp that came with the antenna that is used with a clamp that you might be interested in selling please? Thank you very much.
     
  8. K2QI

    K2QI Ham Member QRZ Page

    When I was a new ham, my very first commercially made antenna was an MP-1. Nice little thing; it certainly got me on the air.
     
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