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Best QRP Antenna for Field Day

Discussion in 'QRP Corner' started by KK4NSF, Dec 9, 2015.

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  1. KK4NSF

    KK4NSF Ham Member QRZ Page

    What i've learned on my mini-QRP-DXpeditions is that the antenna is one of the most critical elements for successful QRP operation. It didn't take long to figure out that if I don't have a good antenna, my signal does not go very far. What I am still working on is what type of antenna is the best for portable / field day / emergency / expedition usage.

    Currently, I'm using two types of antenna for field operations:
    1- Icom AH-703 vertical- a tunable whip with a counterpoise, mounted on a tripod 8' above the ground.
    2- a 65' Random Wire, elevated to 25' or so feet up, tuned with a small tuner..... and a counterpoise.

    Both seem to work well. I think the random wire is a little better on noisy days, but the vertical is easier to set up quickly. I'm sure I can do better.

    What do you use for your field operations? How poratble is it? How well does it work?

    Dave
    KK4NSF
     
  2. AI6KX

    AI6KX Ham Member QRZ Page

    Re your random wire - what bands, how long a cp, what kind of tuner? (I'm trying to work this out for 20, 17, and 15 meters)

    Steve JS6TMW
     
  3. KK4NSF

    KK4NSF Ham Member QRZ Page

    Steve.... I operate on 40m and 20m, with a 65' random wire. The CP is approx 32'..... all tuned with an MFJ 971. I like the built in SWR meter. My support, if there are no trees available, is a used photo tripod, with a 15' fiberglass collapsible pole attached.
     
    AI6KX likes this.
  4. AI6KX

    AI6KX Ham Member QRZ Page

    OK, thanks. My main portable antenna is a parallel dipole for 20, 17, and 15 that works well when I can both ends up at least 20 feet. I wanted to prepare for situations where only a single wire is possible. I got one of the cheap eBay T-network tuners and modified it to work better on the high bands. Your MFJ971 is also a T-network, so that's encouraging. I tried a 40' wire and can tune it easily on the 3 bands, but the 12' counterpoise didn't make any difference whether I used it or not.

    Steve in Okinawa
     
  5. AG6QR

    AG6QR Premium Subscriber QRZ Page

    It depends on the band, plus the local soil conditions, etc. I'd say a 40m beam on 80' crank-up tower would be a good place to start :) .

    I'm only half-joking. You really want the absolute best antenna you can put together. In a great location.

    My club puts together a field day station right on the shore of the San Francisco Bay (great low takeoff angle with saltwater ground plane toward the east), using big antennas on trailerable towers. The night before FD, after the antennas were set up, one of my friends hooked up his Rockmite to the 40m beam. The Rockmite can barely make 500mW. My friend contacted New York from California with easy copy. That's got to win some kind of award for the ratio between the size/weight of antenna versus the size/weight of the rig.

    However, during Field Day itself, it's a lot harder to make long distance contacts with QRP, especially early during the event, when everyone is on the air. The same power level that works really well on a quiet band will be incapable of busting a pileup during the crazy Field Day conditions. If you're willing to operate at 2:00am when the sane people are all sleeping, you may have better luck.

    Two years ago, my wife had planned a family camping trip over the Field Day weekend. I couldn't put on a really strong station, but I decided to bring my radio and operate 1B battery, at 5W, just to see what I could accomplish. I used a Buddipole, set up as a horizontal dipole. As I set up during the half hour before the official start, the antenna was working very well, and I quickly made a several test contacts at distances of 500-1000 miles across the western US. But when the event officially started, my QSO rate dropped precipitously. I think I made 7 contacts in two or three hours of operating. With my good receiver and excellent noise floor at that campground far from the electric grid, I copied probably 40 stations for each one that I contacted. But people just weren't hearing me. I was also handicapped by the fact that I didn't know CW well enough at the time to attempt it, so I was strictly SSB.

    It's ok. I established a baseline from which I'll have much opportunity for improvement.
     
  6. KC3RN

    KC3RN Ham Member QRZ Page

    I use this:
    http://www.qsl.net/wb3gck/dollar_store_special.htm

    I actually modified mine a bit, by splitting the 30 meter counterpoise into a detachable section for 17M.

    It actually works pretty well. In fact, I have two. My little go-bag version, and another (heavier gauge) version I use at my home QTH.
     
    AI6KX likes this.
  7. W1VT

    W1VT Ham Member QRZ Page

    On HF I use a half wave dipole strung between two trees. When I run two bands I string up two dipoles. No tuner needed--just put up the antenna and operate!
     
  8. KI6J

    KI6J Ham Member QRZ Page

    Best can't be achieved, but only approached as time tends to infinity.
    20mBeam_FD.JPG
     
    W4SEX and AI6KX like this.
  9. AB9LZ

    AB9LZ Ham Member QRZ Page

    I use a center loaded vert on the beach, the low takeoff over saltwater makes Europe on 5 watts easy peasy. For backpacking I use an end fed half wave, not having a feedline makes life easy, and lighter.

    73 m/4
     
  10. AA9SD

    AA9SD Ham Member QRZ Page

    I've got a few portable antennas, and LNR Endfedz 40-20-10, a Buddistick, a mag loop and an 18' vertical. I've had the best luck with the LNR and the 18' vertical. The mag loop also works great but has very narrow bandwidth with means a lot of retuning if you QSY a lot. The Buddistick also works well but also requires retuning when changing frequencies.

    Here are some advantages and disadvantages I've found with each.

    The advantage of the LNR is that it works 40, 20 and 10 meters without a tuner.
    The drawback to the LNR Endfedz is that you either need to get the end up into a tree or take along some type of support.

    The advantage to the Buddistick is it is quite small and light when packed and can cover 40 meters to 6 meters.
    The drawback to the Buddistick is fiddly and frequent retuning.

    The advantage to the mag loop is it is directional and you can often null noise by turning it.
    The drawback to the mag loop is frequent retuning and the control box is large.

    The advantage to the 18' vertical is that with a tuner it will cover 20 meters to 6 meters and it collapses down to about 4' for transport.
    The drawback to the 18' vertical is that it needs radials to really do the job.
     
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