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Thread: Portable QRP antenna

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  1. #1
    Join Date
    Sep 2007
    Posts
    62

    Default Portable QRP antenna

    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.


    Jeff / KE5PIH

  2. #2

    Default

    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 (http://www.hfpack.com/antennas/) 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...

    73,
    Larry - NK2X

  3. #3

    Default

    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!
    "A Republic, if you can keep it."

  4. #4

  5. #5
    Join Date
    Sep 2007
    Posts
    62

    Default

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

    Thanks

    Jeff


    Quote Originally Posted by nk2x View Post
    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 (http://www.hfpack.com/antennas/) 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...

    73,
    Larry - NK2X

  6. #6
    Join Date
    Sep 2007
    Posts
    62

    Default Thanks to all who responded....



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


    Thanks,


    Jeff

  7. #7

    Default

    Quote Originally Posted by KE5PIH View Post
    Thanks Larry, I was looking for something backpackaple. The end fed half wave wire looks like it would be easy to use.
    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: http://www.w5dxp.com/notuner.htm
    73, Cecil, www.w5dxp.com
    Can CO2 emissions save us from the coming ice age?

  8. #8
    Join Date
    Apr 2006
    Location
    Bristol, MD
    Posts
    2,222

    Default

    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
    Ham radio is something you DO and LEARN. NOT something you BUY!

  9. #9
    Join Date
    Jan 2000
    Location
    Commerce MI (Detroit area)
    Posts
    8,024

    Default

    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 !
    73.....JD, FISTS #3853,cc 455,SKCC # 1395,tribune #12,
    Official US Taxpayer

  10. #10

    Default

    Quote Originally Posted by k8jd View Post
    My rule of thumb is the smallest (QRP) rigs need the BIGGEST antennas. Just to make it fair.
    Have Fun !
    But it's tough packing in that SteppIR and Rohn25 to the campsite.
    We've been smeckledorfed!

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