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160 meters and tarheel question.....

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by KB4MNG, Jun 18, 2019.

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  1. KB4MNG

    KB4MNG Ham Member QRZ Page

    Finally got a day off and tried 160 on the Ground mounted tarheel. Fully extended I get 1 to 1 in the area of 2.5. Just not enough coil for the ham section.

    What I have now attached to the top of the coil is a 3 ft copper pipe with a fairly large capacitance hat. Works t great on the other low bands. Could I add an 8ft whip to the top of the cap hat and achieve 160 meters or will I be wasting time trying it.....

    thanks
     
  2. WA8OLN

    WA8OLN Ham Member QRZ Page

    When I used mobile antennas at home on 160 back in the 60's I used to think of the coil and whip as a tuned circuit and you had to add more of one or both to bring down the resonant freq. to where you wanted it.
     
  3. K0UO

    K0UO Subscriber QRZ Page

    Get a Scorpion it will load on 160!!!
     
    NH7RO likes this.
  4. KC8VWM

    KC8VWM Ham Member QRZ Page

    The more radiator length you add, the less coil you will need.
     
    NH7RO likes this.
  5. NH7RO

    NH7RO Ham Member QRZ Page

    Yes, but event the big 680 needs an additional coil on top to resonate down there. This is one case where the bigger everything the better---but efficiency will still be way down over a full ground plane or decent inverted L Unless you're over salt water.
     
  6. K7TRF

    K7TRF Premium Subscriber QRZ Page

    Additional whip will help on 160m but it may prevent you from obtaining a match on some of the higher frequency ham bands. If the antenna will primarily be used on 160m, 80m and maybe up to 40m this shouldn’t be a problem but if you make the combination of physical height and cap hat loading longer than 1/4 wavelength on a given band then a screwdriver type antenna won’t match on that band. You could set up the extra whip length with an alligator clip so you can add it for low band operations and remove the extra wire when you want to work higher frequency bands.

    As others have posted a screwdriver antenna with a lot of capacitive and inductive loading won’t generally be very efficient on 160m and will need to be retuned frequently as you tune around the band with its narrow SWR bandwidth. That’s just the price you pay with an extremely short and heavily loaded antenna. But it can still get you on the band and any working antenna beats no antenna every time.
     
    NH7RO likes this.
  7. KI5FJ

    KI5FJ Ham Member QRZ Page

    Brian, The physically short antenna you are attempting to operate on 160-Meters is not efficient. The Z-Matching losses will be significant.
    When operating, the results will be disappointing. 73, Joe O, K I 5 F J, NNNN
     
    NH7RO likes this.
  8. KF4ZGZ

    KF4ZGZ Ham Member QRZ Page

    Or you could just whip up another coil to add in between the existing coil and the copper pipe.
    It wouldn't need to be much ..... I'm guessing 20-25 turns or so on a 2 in. or so pvc form would be plenty.
     
  9. KB4MNG

    KB4MNG Ham Member QRZ Page

    Thanks for the advise. I have operated 160 before so I definitely know the limitations. I like experimenting with compromise antennas. I plan on parking this on a cw freq this winter and call cq and see what contacts I can make.

    Anything thing I put up for 160 at my current location will be a compromise!
    thanks!!!!!
     
  10. W5LZ

    W5LZ Ham Member QRZ Page

    Can you make a Tarheel work on 160 meters? Sure, if it's "big" enough. That "big" can mean several thing and combinations of things. Very basically, you need additional length, which can get unreasonable very quickly. Or a larger coil/inductance, another sort of unreasonable thingy. The Tarheel can have both of those 'things' added to make it work on 160 meters. At what point do YOU find it unreasonable? The 'catch' to adding length is that the 'smaller' you make the end resulting antenna in relation to wave length, the less effective/efficient it is. Almost all HF mobile antennas are very inefficient to start with, maybe 2 - 3%, and that's being generous! Wanna do it? Hey, why not?
     

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