Most Efficient Antenna for QRP

Discussion in 'QRP Corner' started by W7CJD, Dec 15, 2015.

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  1. W7CJD

    W7CJD Ham Member QRZ Page

  2. KC8VWM

    KC8VWM Ham Member QRZ Page

    No the wire ball wound up inside the reel at the end of the antenna, is basically just the same thing as the ball mounted at the end of your car antenna. It has little or no effect on antenna measurements / tuning especially on HF bands. In fact, it might even prevent corona from occurring.

    I have used it QRP, QRO and many times using 100 watts during field day. It can handle full legal power all day long if you want it to, but I primarily use it for portable QRP work.

    I have also used it outside as a temporary antenna in my backyard for several months. It's been well used and abused and it just keeps on working. I first constructed it in 2004 and I still have this same exact antenna today in 2015.

    It can be hung up in a tree, or on a portable telescopic pole, or mounted anywhere in between. It's my favorite "go to" portable antenna mostly because it's very quickly deployed. You just unwind the reels. Takes only a few minutes to set up. Same thing with taking it down again. Just wind it all back up.

    It all fits inside this handy nylon carry bag, including the tent pegs and feedline.

    [​IMG]
     
    Last edited: Dec 21, 2015
  3. KC8VWM

    KC8VWM Ham Member QRZ Page

    More photos... :)

    Preparing the antenna...

    Removed from the storage bag and setup on the telescopic painters pole.

    [​IMG]

    The rope loop seen installed at the top of the PVC cap is used when you want to hang up from a tree branch.

    The end of this 20' painters extension pole has a plastic section (insulator) at the top intended for an accessory attachment, so I am merely resting the PVC cap on top of it.
    It doesn't affect the electrical connections made inside the PVC cap.

    [​IMG]

    Here I am unwinding the reel for the intended band of operation.
    Band of operation is noted by the white paint mark made on the antenna wire.

    [​IMG]

    Portable antenna is now deployed, secured and ready for operation...

    [​IMG]

    [​IMG]
     
    Last edited: Dec 21, 2015
    DK7OB and KU4X like this.
  4. W4SEX

    W4SEX Ham Member QRZ Page

    I wish that there was a testing site that would test all antennas and give them an efficiency rating.
     
  5. W7CJD

    W7CJD Ham Member QRZ Page

    It would be a considerable help, if wire antennas were modelled.

    Then, we could readily see optimum height for maximum lobes, choosing direction of lobes by height, and lobes and nulls.

    I would like to see dipoles, ladderline-fed "doublets".

    Next, end-feds.

    Next, horizontal and vertical loop antennas, and deltas.

    Next, I would like to see bazooka and double bazooka antennas.

    I would also like to see Lazy-H.

    ..any other wire antennas of interest?
     
  6. KI6J

    KI6J Ham Member QRZ Page

    I sometimes use a 20m half-square fed near the ground with my EFHW matchbox. It is a good performer, and well worth the extra effort to set up.
     
  7. W7CJD

    W7CJD Ham Member QRZ Page

    Last edited: Dec 23, 2015
  8. KI6J

    KI6J Ham Member QRZ Page

    I have used two 21 foot kite poles, a line between a kite pole and a tree, and a line between two trees. An attribute of the antenna is that it doesn't have to be very high to be effective- just enough to get the ends about 5 feet off ground.

    I use my 40m dipole and configure it as a 20m half square; I have a 2 turn coil I put between the dipole legs to get the extra length to tune it. My EFHW matchbox is a parallel resonant autotransformer. I have a switchable tap on the transformer to match high-Z EFHW antennas, and the meduim-Z half square.
     
    W4SEX and W7CJD like this.
  9. KI6J

    KI6J Ham Member QRZ Page

    Last edited: Dec 25, 2015
  10. KI6J

    KI6J Ham Member QRZ Page

    I built a portable version of the KZ3K phase controller. I've used it with a pair of full-wave vertical loops on 20m and a pair of dipoles on 30m with excellent results
    PhaseControl.JPG
     

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