Does the MFJ-1984MP need a tuner? I put it to the test.

Discussion in 'Amateur Radio News' started by K5QBF, May 26, 2021.

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  1. KG8LB

    KG8LB Ham Member QRZ Page

    Using a Myantennas 7510-2k EFHW. The feed is at 4 ft , the vertical portion runs to 40 ft high. The remaining 100 ft is horizontal at 40 ft.

    The antenna works fine on all bands, the Icom 7300 tunes most anywhere. It also works well in most cases on WARC bands. I use it often on 60m as well. The Icom tunes on 60m as long as l do not use the ground terminal on the feed box.

    I am perfectly happy with the installation, operation and especially, the performance of this very versatile antenna.
    M1WML likes this.
  2. K9UR

    K9UR Subscriber QRZ Page

    Huh? they may be quieter by reducing high angle incoming signals, but isn't most man-made noise vertically polarized?
    I've never (in real life) used a vertical that was any quieter than a properly installed dipole. Usually the vertical was noisier...

    'splain than...
    M1WML likes this.
  3. W1YW

    W1YW Ham Member QRZ Page

    I can't account for your experience, nor shall try. The point is that the solid angle coverage of the vertical nulls at high angles. Right now, with the poor SFI , the SKY NOISE is quite pronounced and has significant contribution from high elevation angles. That sky noise is produced and. or propagated in the atmosphere, with some being cosmic in nature as well. When you cut out that solid angle coverage you cut down that contribution. That is why Yagis (for example)are so prized---they are unidirectional and cut out most solid angles that are not being sought in the link, both at high elevations AND at most solid angle azimuths.

    That noise is not man made BTW.

    What I described is not a polarization issue. That's separate.

    Chip W1YW
    M1WML likes this.
  4. K9UR

    K9UR Subscriber QRZ Page

    Ah...ok, so not polarization... Sky noise, then, in overly simplified terms is the background noise due to "solar weather / cosmic activity" Does that also include lightning ?


    I've found that Lightning (and man made) noise is bad enough in summer months that a vertical on the low bands can be almost worthless with the S9+60 static crashes and resulting AGC action. It's why my 160M vertical antenna comes down in March and doesn't go back up until thanksgiving.
    M1WML likes this.
  5. W1YW

    W1YW Ham Member QRZ Page

    My point is that a low dipole has some use for DX, and raising it helps. Keeping it below 1/4 wave high does not.
    M1WML and K9UR like this.
  6. KC4IGO

    KC4IGO Ham Member QRZ Page

    Which push up pole did you use? Kc4igo
    M1WML likes this.
  7. WA1ZCN

    WA1ZCN Ham Member QRZ Page

    I recall reading about another field test with this antenna, and they made the point that the height of the transformer and end of the wire element can have a big effect on SWR. That might be what you were seeing when you switched from the inverted V with the transformer near the ground to the inverted L with both ends closer to the ground. Might be worth an experiment.
    M1WML likes this.
  8. NM7L

    NM7L Ham Member QRZ Page

    End-fed half-wave … end-fed quarter-wave … end-fed eighth wave …

    Aren't they all just "long wires"?

    Creative marketing techniques don't change what they really are.
    M1WML and K5QBF like this.
  9. K5QBF

    K5QBF XML Subscriber QRZ Page

    It’s the Spiderbeam 12m
    M1WML likes this.
  10. K5QBF

    K5QBF XML Subscriber QRZ Page

    Actually the length of the wire is what signifies the wave. So for a 40m end fed half wave the element is 65.5ft long.
    40m is 131ft. So a full wave element is 131ft, a half’s wave is 66.5, a quarter wave is 32.7ft. An end fed cut to be resonant on a specific frequency is what sets it apart from a random wire which is cut so that’s it’s not resonant any frequency or it’s harmonic.
    M1WML likes this.

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