Easiest to make portable 2m/70cm antenna?

Discussion in 'VHF/UHF - 50Mhz and Beyond' started by KD2QQF, Aug 15, 2019.

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  1. KD2QQF

    KD2QQF Ham Member QRZ Page

    With easily fond/cheap/on hand parts?

    Was hoping I'd come across some twin lead to make a J-pole but no luck(Even amazon prices seem way high) and I may have a need for one this weekend. Got the next 2 days off so time to build it before hand but not a lot of money to spend on this. Past attempts at wire antenna's have resulted in off the chart SWR numbers so I not wanting to go that direction.

    Plan is for the antenna to mount to the top of an extendable pole. Pole is about 12-15' long, fully extended. It was originally designed to hang a TV from the ceiling is a store. I'm in no way worried about strength of the pole or mounting the antenna to the pole, just what kind of easily transported antenna would be best to build. If I could find decent priced twin lead I'd go for a twin-lead J-pole.

    Radio connected will be an Anytone AT-d868uv(7w), Baofng UV5Rv2+(5w), and possibly a TYT TH-8600(25w). Potentially connecting either to a 60w out 144mHz amp.
  2. VE3CGA

    VE3CGA XML Subscriber QRZ Page

    I guess this is for portable use...
    If your mounting pole is not metal you might try a coaxial vertical dipole
    like this http://www.hamuniverse.com/w4bwsverticalbazooka.html
    or a coaxial collinear antenna
    like this http://www.srgclub.org/CollinearAnt-HomeBrew.html
    both are made from coax.
    I used the coax vertical for mobiling with very good results, I out it in a 10' piece of 3/4" white plastic water pipe from home depot

    I don tknow where you would get 300ohm twinlead unless a local ham can donate some, wouldnt take much for a j pole.
    I made one from 1/2" copper and it worked good. My son used it on Toronto and continues to use it now
    in BC where he can hit a number of repeaters.

    Back in the old "repeater" days there was a repeater being tested at a hams house down the block. they had a coaxial collinear built and it hung from a tree initially, no pole needed.
  3. K3UJ

    K3UJ Ham Member QRZ Page

    SO-239 panel mount. Make a ground plane with 19" solid copper wires. Vertical attached to center pin, four radials off the screw holes. Tape to top of pole. Bend the radial up for transport.

    Won't last forever, but it's cheap and quick. There are pics of these out on the web.
    AI3V, K6CLS and N0TZU like this.
  4. N0TZU

    N0TZU Platinum Subscriber Platinum Subscriber QRZ Page

    Since 300 Ohm twin lead is hard to find, has anyone tried making a roll-up J-pole from zip cord?
    N8MLP likes this.
  5. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    450 Ohm window line is a better idea, and readily available from almost all "ham" cable distributors in cut lengths, like here where it's $0.27/foot. You only need about five feet to make a 2m j-pole: https://rfconnection.com/balanced-lines/
  6. N0TZU

    N0TZU Platinum Subscriber Platinum Subscriber QRZ Page

    Yes but I’m wondering if anyone has tried zip cord.
  7. KD2QQF

    KD2QQF Ham Member QRZ Page

    Pole is metal, but the coupler between sections is an insulator and it's powder coated.

    Yes to portable use. Don't know any local Ham's. Also tried Coax and had no success. No antenna tuner so no idea how to improve as SWR numbers were off the chart so much radio cut power.

    Tried solid copper with no success. No antenna tuner and SWR was off the chart so much radio cut power.
    Has anyone actually tried this. I've got materials but no idea how to make it work. Since it's unshielded and directly side by side, it would be had to get it right.
  8. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Logically that really shouldn't work. Zo of zip cord (typical plastic insulated lamp cord) is around 70 Ohms but not guaranteed to be anything in particular; the insulation is thicker and not specified for d.c. but Vf would be lower, and I'd think trying to find a suitable tap point to feed it may be very difficult.

    Most "zip cord" isn't even rated for outdoor service.

    When much better stuff is available for $1.50 total cost, I'd use that.:) (420-450 Ohm window line actually works better than 300 Ohm twin lead for this application.)
  9. WA9SVD

    WA9SVD Ham Member QRZ Page

    "Zip cord" can be used in a pinch as a RADIATOR on 2 Meters, but NEVER as a feed line. :( The loss, small spacing and small conductor size of some (most?) is just too great (err, too little?:confused:) to use it as a feedline; stick to coax and decent insulators, even for "temporary" antennas.
  10. ND5Y

    ND5Y Ham Member QRZ Page

    2 m dipole with a close spaced 1/2 wave 70 cm coupled resonator. Easy to make from stiff wire, rod, tape measure, or small diameter tubing.

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