Discussion in 'Antennas, Feedlines, Towers & Rotors' started by K9KXW, Feb 19, 2010.

Thread Status:
Not open for further replies.
ad: L-HROutlet
ad: l-rl
ad: Subscribe
ad: Left-3
ad: Left-2
ad: abrind-2
ad: L-MFJ
  1. K9KXW

    K9KXW Ham Member QRZ Page

    Hey there Everyone,

    OK, here's what I have.

    100 feet of 14 guage stranded wire and Rig is a Yaesu FT-857D and an LDG AT100Pro auto-tuner.

    I've been doing a lot of googling and reading on vertical wire antennas, and I came across a website that I thought was very interesting and want your ideas and suggestions.

    Here is the website " http://www.wa0itp.com/longwire.html ".
    The part that I really found interesting was the (SPREADSHET) for the odd wavelengths that they are showing.

    A couple of questions though:

    1. The LDG AT100Pro autotuner DOES NOT have a BINDING POST to connect the wire. So should I mount a binding post in the tuner, or just solder the antenna wire to a PL-259 connector in the center conductor?

    2. Should I use the lengths of wire that they show, or should I just use my whole 100 foot of wire which will be approximately 65 - 70 foot vertical and the rest horizontal (INVERTED-L)?

    Sorry if it seems like a DUMB question, but I just had another mini- stroke a week and a half ago. I want to make sure my brain isn't to fried. HIHI

    Thanks in advance.

    73 Jim
    Last edited: Feb 19, 2010
  2. KR2D

    KR2D Ham Member QRZ Page

    No need to add a binding post to the tuner, unless you want to.

    You can solder the wire directly to the center conductor of a PL-259, as you suggested.

    Or, you can use a banana plug on the wire - they fit perfectly into the center hole of the SO-239. You can get banana plugs at Radio Shack.
  3. AD7N

    AD7N Ham Member QRZ Page

    Clever! I will have to try this sometime.
  4. K9KXW

    K9KXW Ham Member QRZ Page

    """HOW MUCH WIRE"""

    Thanks Ron for the Connector answer.

    Now for the other part of my question.

    I have 100 Feet of 14 guage stranded wire (BRAND NEW), BUT I don't how much to use. I did some googling and reading and more googling and reading and I found an interesting website http://www.wa0itp.com/longwire.html .

    The (SPREADSHEET) was interesting and I would like some input from of you more "seasoned wire antenna enthusiast". I am also putting the SPREADSHEET at the end of this post.

    Thanks in advance for any suggestions or info.

    73 Jim

    Long Wire Antenna Length Calculations

    Proposed length (feet) 226
    Wavelength Multiple of these bands using 492/Fmc

    160 Meters 0.826829268
    80 Meters 1.607723577
    40 Meters 3.215447154
    30 Meters 4.639430894
    20 Meters 6.430894309
    17 Meters 8.299528455
    15 Meters 9.646341463
    12 Meters 11.43321138
    10 Meters (low end) 12.86178862
    10 Meters (high end) 13.64268293

    380' looks good
    310 looks very good
    130' looks ok
    80-90 also
    78 also

    Alan Chester (G3CCB)(SK) proposed a solution for the high impedance of a 1/2
    wave, end fed antenna. Mr. Chester rationalized that there might be some
    impedance-friendly length of wire usable for an end-fed antenna - near 1/2
    wave - that didn't present the tough-to-tune, high-impedance load on a
    select set of bands. In short, he proposed wire lengths in the 1/8 - 3/8 or
    5/8 - 7/8 wavelength range, staying away from the 1/2 wave length (or
    multiples thereof).

    In his article "Taming the End-Fed Antenna" (reprinted in "The Antenna
    File", RGSB, pg 118) he looked at this issue by plotting various 1/2 wave
    lengths and proposed:

    - 26.5m (86.9 ft) for 160 - 10M use
    - 15m (49.2 ft) for 80, 40, 20, 17, 15, 12, 10M use
    - 10m (32.8 ft) for 80, 40, 30, 17, 15, 12, 10M use

    The idea is to pick a length that doesn't fall on or near the 1/2, 1.0, 1.5
    (etc.) wave length points of the bands of interest.

  5. G3TXQ

    G3TXQ Ham Member QRZ Page

    Unfortunately, the simplistic formula he uses in the spreadsheet doesn't take account of many "real-world" effects. For example a wire which is half-wave resonant at frequency F, is not three-half-wave resonant at 3*F. And the formula takes no account of the fact that a wire at fixed physical height is at a different electrical height on every band.

    Why not download the free demo version of EZNEC and try some lengths for yourself. You'll find that every one of the lengths he quotes has an impedance greater than 2000 ohms on at least one band. Height above ground will affect the outcome, as will wire insulation.

    Steve G3TXQ
  6. K9KXW

    K9KXW Ham Member QRZ Page

    """"" WIRE UPDATE """""

    Well I made my decision and just put up the """WHOLE 100 FEET""" of 14 guage wire that I purchased as an (INVERTED-L).

    Well I have a """GREAT""" SWR from (80 meters through 6 meters) running just the 100 foot wire VIA PL-259 center pin into my (LDG Electronics AT-100Pro Autotuner), makes me happy. :D :cool:

    Thanks for the suggestions and guidence.

    73 Jim
  7. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Low SWR means the tuner is doing its job, and not much more than that. Some of the best antennas in the world would have a terrible SWR.

    What makes an inverted-L work well is the radial system below it.
  8. KE7TBB

    KE7TBB Ham Member QRZ Page

    if you get tired of the verticle....

    try a horozontal loop!!! the bigger, the better...
    that tuner will handle anything the loop will do
  9. CT2FZI

    CT2FZI Ham Member QRZ Page

    Loop :)

    Another loop vote.

    I guess that you will find that the loop is a great all band performer.

    Just feed it with ladder line in any point and the tuner will do the rest :)

    Luis, CT2FZI

  10. AD7N

    AD7N Ham Member QRZ Page

    I third vote for a horizontal loop!

    I am running a horizontal loop right now, slightly more than full wave on 80m. It's fed from the top of my tree @ 50ft, and is in sort of a triangle pattern. The two bottom corners are only ~12ft above ground (The loop is pointed south, and I am on a small hill with south facing view). It is fed with ladder line up the trunk, and connected to my remote tuner located at the bottom of the trunk. I feed the tuner with coax ran underground through a pipe that goes to the shack. The tuner control cable is ran also run to the shack.

    If you can run ladderline to the autotuner directly that is the way to go. If not (buried line, for example), a well-built balun at the end of a coax run can also feed ladder line.

    As has been noted already, loops are very forgiving. The main key's are get it up as high as possible, and use as much wire as reasonably possible. The tuner will take care of the rest.

    I've gotten excellent performance from 80m on up. Even with the bottom legs at only 12ft, I am able to hit California (I'm in Seattle) with only 5 watts on 80m! On 40m & 30m I get good DX performance. On 20m-17m-15m and up, the loop has very good directions and very sharp nulls. This can be a mixed blessing :rolleyes:

    a simple 20m dipole has better overall gain than my loop because it doesn't have such deep nulls. However, in certain directions the loop beats anything I can put up that's as simple.

    Just some food for thought, best luck with your setup!
Thread Status:
Not open for further replies.

Share This Page

ad: elecraft