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Portable QRP antenna

Discussion in 'General Technical Questions and Answers' started by KE5PIH, Apr 12, 2008.

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  1. KE5PIH

    KE5PIH QRZ Member

    I have a Yaesu FT-817 ND which is a Low Power HF rig. I am trying to understand what I can use for a portable antenna. I have a Buddipole, but was looking to use something even easier to deploy that that.

    What would be some ideas to look into or consider....?
    I enjoy 40 & 20 meter.:confused:

    Jeff / KE5PIH
  2. NK2X

    NK2X Ham Member QRZ Page

    Hi, Jeff.

    Some info might make any answers more useful.

    What are your operating modes (i.e., are you looking for portable, semi-portable, back packable, or home use)?

    Also, what are your expectations as far as performance? With antennas that are more easily deployed (that usually means smaller or less efficient), efficiency becomes a factor (especially with QRP).

    It's pretty hard to beat an end-fed half wave wire with one end tossed up into a tree and it only requires a simple matching circuit for low power. They're easy to make but if you want commercial, then the Par EndFedz are hard to beat (look for the low-power 3-bander). There are any number of usable short verticals out there ... take a look at the HFPack site ( for their shootouts on verticals and horizontal antennas for portable work.

    And finally, the Buddipole is pretty hard to beat for efficiency...not too hard to deploy, especially in the vertical configuration...maybe too much for backpacking, though.

    Hope this helps some...

    Larry - NK2X
  3. W4HAY

    W4HAY Ham Member QRZ Page

    There's a design for a 40/20/15/10 trap dipole in the ARRL Antenna Book. Depending on how you make the traps, it could be very lightweight. The traps consist of 27 pF capacitors in parallel with 4.7 uH inductors. The inside elements are 16-2/3 Ft. and the ouside legs are 10-1/2 Ft. It's fed with either 50 or 72 Ohm coax.

    When (if?) the sunspots begin to increase, 15 could wind up being your favorite band!
  4. KC9ECI

    KC9ECI Ham Member QRZ Page

  5. KE5PIH

    KE5PIH QRZ Member

    Thanks Larry, I was looking for something backpackaple. The end fed half wave wire looks like it would be easy to use.



  6. KE5PIH

    KE5PIH QRZ Member

    Thanks to all who responded....


    I did not want to sound as though I ONLY appreciated Larry's comment.


  7. W5DXP

    W5DXP Ham Member QRZ Page

    I backpacked a lot when I lived in Central California and there were always trees around. If one has trees available, a twinlead-fed dipole is hard to beat. The twinlead length can usually be adjusted so that no tuner is needed. To get ideas about such an antenna:
  8. K3WRV

    K3WRV Guest

    ME? I use a hunk of Baygard(tm) wire wound up on a spool and just toss it over a tree branch - weighs less than 8 oz. Feed it thru an L network tuner (in my case, MFJ 16010). Weighs a couple of oz's.

    Alt: Have used a "twinlead" ribon cable dipole and fed it withj RG-??? (58 or 59) and no tuner. Think mine was cut for 40/20 or 20/15. Could feed it as a momopole and it worked on 10 too. No tuner, bnut the COAX was heavy (~30 Feet).

    Have heard RG-174 works FB if the run is fairly short.

    de Bob
  9. K8JD

    K8JD Ham Member QRZ Page

    My rule of thumb is the smallest (QRP) rigs need the BIGGEST antennas. Just to make it fair.
    That halfwave of wire thrown up into the tall tree is an idea that I had when I started taking a QRP rig camping.
    No feedline to carry, no ground counterpoise required and the results usually are good just using a small tuner to match the high Z to the radio..
    A small NiCd battery and some kind of charger, my old J-38 key, a few hand tools, tape measure (for tuning) and a notebook and pencils for logging completes the kit.
    Have Fun !
  10. KC9ECI

    KC9ECI Ham Member QRZ Page

    But it's tough packing in that SteppIR and Rohn25 to the campsite.
  11. KC9NFB

    KC9NFB Ham Member QRZ Page

    Will the end fed work on multiple bands (80-10m) if I use a tuner? I know we are talking QRP, but can higher power (100w) be used with this type of antenna?
    Last edited: Apr 13, 2008
  12. NA0AA

    NA0AA Ham Member QRZ Page

    The buddipole shines in that it's a well integrated package and it can be set up on dead level ground in the middle of nowhere with nothing taller than 1" above the ground.

    Way to heavy for backpacking most of the time, I agree - thinnest end-fed wire I could manage, and if you fish, you have a great way to launch it. smallest tuner you can manage to balance it out.

    I'm making a heavier trip but still space limited, I'm taking a buddipole and a ladderline fed doublet make of 18 ga wire, along with a tuner and balun. When I'm short on time, buddipole, if i'm going to be there a few days, I can hoist up the Doublet for a full size 80 meter dipole.

    One thing I have wanted to try is to use very thin insulated wire wound on retired fly-reels - similar to the old collins tape measure, but the spools go to the end instead of the center.
  13. KC9NFB

    KC9NFB Ham Member QRZ Page

    anyone please?
  14. W6GQ

    W6GQ Swap Meet Moderator QRZ Page

    The Outbacker Joey is a junk antenna,,,

    If anyone has one I will take it off your hands so you dont get embarassed owning it. ;):D:p
  15. G0GQK

    G0GQK Ham Member QRZ Page

    Best thing to do is Google, QRP and read all about what people do who are enthrusiasts. Spend time on your computer finding rover sites, and you will get some ideas which might br the most suitable for you. People often suggest an end fed and throw it in a tree. What about if there are no trees ?

    Lots of ramblers use a lightweight fibreglass pole, check out SOTA poles for some ideas. They attach a thin wire to the pole, use a radial with a small ATU and then tune about 3 or 4 bands.

  16. KC9ECI

    KC9ECI Ham Member QRZ Page

  17. AB9LZ

    AB9LZ Ham Member QRZ Page

    End Feds are resonant (and need to be), my multi band model is nothing more that several hanks of labeled wire that I tie together with wire nuts depending on the need, when backpacking I only operate for an hour or two at the most, the time of day selects the band.

    The tiny transmatch that sits at the end of the antenna has a tapped toroid and an air variable (much better Q than the cheapo transistor radio caps). Tune for the highest background noise and fire away.

    My cigarette pack size transmatch has managed 80 - 100 or so watts with little sign of heating.

    73 m/4
  18. KC9NFB

    KC9NFB Ham Member QRZ Page

    What is your opinion on Yo Yo tennas? Seem to be the ticket for adjusting wire lengths.
  19. KE5PIH

    KE5PIH QRZ Member

    How are end feds resonant?

    It was stated above that end feds are resonant.... How is that? I ordered the Par Electronics 10-20-40 End Fedz that was noted at the beginning of this thread. I have not recieved it, it seems the military buys as fast as they are made, but I am in the que.

    To go from 10 to 20 to 40 meters, will I have to make a physical change to the coil or the wiring on the antenna? I am a newbie, only been a ham for 11 months.

    Jeff W.Waldrop / KE5PIH
  20. AB9LZ

    AB9LZ Ham Member QRZ Page

    To answer the second part of your question first, no, I don't think so, I'm sure Par has a scheme that allows for an automatic proper match on those bands.

    There is a slight confusion of terms here. You can end feed a piece of wire of any length and get it to work (the longer the better though) this is referred to as a long wire or a random length wire. Typically this requires a good counterpoise to get it to work and anything shorter than a half wavelength won't work so well.

    When the wire is resonant (for a given frequency) the name changes to an End Fed Half Wave antenna. The wire then takes on the advantages of a dipole, without the limitations of it's non resonant brethren, for example although most folks continue to use a counterpoise, there are times that it isn't entirely necessary. Another advantage is that the current distribution (like the dipole) is at it's greatest at the center... i.e. you want that part of the antenna to be at the highest point. So, throwing the wire over a high branch, with one end near the rig, and the other staked out away with some tent guyline, turns out to be as good as a dipole (setup the same way), without the hassle of the feedline. Perfect if you are backpacking.

    73 m/4
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