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Good multi-band wire antenna < 75' long

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by KD0KZE, Apr 7, 2021.

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  1. KD0KZE

    KD0KZE Ham Member QRZ Page

    I worked a decade with a G5RV hung between two trees only about 90' apart, which meant that I had to do bad things with the remaining slack. It was hung over a branch which inevitably wore at the insulation, frayed the wire, and caused it to fail prematurely. After going through a new G5RV every ~3 years, I'm done with it.

    I've been building and hanging single-band dipoles with great SWR, and will look into building some fan dipoles in my secondary (shorter) location, especially for more oddball bands.

    But I still have that vacant spot about 90' long. Height is about 30-35', closer to 40' at one end. I would like to use only about 75' or less, to keep the end insulators further from the trees. I need 40m & 20m and ideally at least two out of these: 17m, 15m, or 10m. What's a reasonable (compromise) multi-band antenna? I've looked at:
    • Alpha Delta DX-EE. People say that 40m is very narrow?
    • G5RV Jr.
    • The DX-CC is 85' long, just a bit too long for this spot -- and the extra wires would be more prone to irritation by branches.
    • The ZS6BKW and close variants are a bit shorter than the G5RV but need to be hung higher than my place allows.
    Any other possibilities? I would consider building my own multi-band fan dipole and hanging it in this spot, except that it's relatively difficult to raise/lower and make adjustments in this location and would like to throw up something already generally worked out here. (And I can't test it at my secondary location since it's too narrow there.)

    73, KD0KZE / Paul
     
  2. KX8C

    KX8C QRZ Lifetime Member #153 Platinum Subscriber Life Member QRZ Page

    My answer to this question was to throw up as much wire as I could as high as I could manage, then run ladder line to a tuner. 73 de KX8C Jim
     
    K7WFM, AB8JC, W6MK and 4 others like this.
  3. WA7ARK

    WA7ARK Ham Member QRZ Page

    A 40m dipole is ~67ft long.
    A 60m dipole is 88.7ft long.

    Are you trying for 80m? If so, you will likely need to use loading coils (or traps). One pair of coils can make a dual band 80/40m dipole that will fit into your space, however, the bandwidth on 80m is a sliver.
     
  4. WA7ARK

    WA7ARK Ham Member QRZ Page

    K0UO likes this.
  5. KX8C

    KX8C QRZ Lifetime Member #153 Platinum Subscriber Life Member QRZ Page

    Ya I was looking for the edit button also. Likely a temporary issue with some behind-the-scenes code. I'm sure it will be back.

    Another way is to put up as much wire as high as possible, then run ladder to a W5DXP style setup where one adjusts the ladder line length to get a reasonable 50-ohm match, then a balun and coax back to the rig. No tuner needed. I was always intrigued by this, but by then i had drilled holes in the house for managing the ladder line.

    73 de KX8C Jim
     
  6. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    You can manage the ladder line inside the house also, if you have the room to do that. Making big loops separated by a couple of inches between loops works.
     
    KX8C likes this.
  7. W3TKB

    W3TKB XML Subscriber QRZ Page

    I am in the process of putting up an inverted "L" wire antenna, total length of the wire is right around 100 feet. Straight out of the ARRL book " Small Antennas for Small Spaces", chapter 3 page 12. Mine is going to go up 35-40 feet and then over on the horizontal 60-65 feet. Remote antenna tuner at the base. Just finished laying out and tacking down all my ground radials yesterday in fact. According to the book, this length wire (100 feet +/-) coupled with the remote tuner will work all bands 160-6 meters, although the upper and lower extremes are low on my priority wants. If it produces on 80-20 meters, that will be fine with me...anything else is a bonus. If you have the book, check it out. If not, let me know, and I could send you copies of just that antenna layout.

    Brando
     
  8. K8JD

    K8JD Ham Member QRZ Page

    My Latest Antenna Solution.
    I put up a temporary antenna since my five main, low band, antennas had coax runs where large machines were digging in a new sewer line behind the house.
    (The coax was removed and stored)
    I used the mounting pipe where my old vertical was, rewired a buried coax line connection to three inverted "L" Quarterwave wires, one cut for 20 M, another for 40 and one for 80M.
    The wires went up in a tree and over to other trees and a flagpole to keep them up around 12-20 ft.
    So far made some decent QSOs .
    I Have Low SWR, direct, coax fed, on all three bands. No baluns, loading coils, or tuners, and on 60 and 30 M with a MFJ versa-tuner in the shack. .
    Hanging in there until May when the construction work should be done and I can get my good antennas back in service.
     
    Last edited: Apr 8, 2021
  9. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Actually, it's 82' long and every dipole that long supported only at its ends will have sag in the middle, so it really only occupies about 77 feet of horizontal space if tensioned to about 50 lbs. I think you have enough room. The A-D DX-CC also is made of very tough insulated wire that's pretty abrasion resistant, but to add even more abrasion resistance if needed, just slip a few feet of 1/2" water hose or similar over each end and secure it in place with vinyl tape. It covers the whole band on 10-15-20-40m and not the whole band on 80m, but even a full-length dipole can't do that. On 80m, it will cover the section of the band you adjust it for and is good for about 100 kHz without a tuner; it will "cover the whole band" with a good tuner (transmatch) with very little sacrifice in performance, although there is some.
     
    AB8JC likes this.
  10. WA9PND

    WA9PND Ham Member QRZ Page

    I've had very good luck with my 66' off-center fed dipole, 25' AGL. Fed 12' from one end through a 4:1 balun (and a 1:1 choke). It covers 40, 20, 15, 10, and 6m with no tuner and SWR's less than 2:1.
     

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