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Is this a GAP antenna?

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by ZL3GSL, Feb 21, 2009.

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  1. ZL3GSL

    ZL3GSL Ham Member QRZ Page

    I've just acquired what is said to be a GAP vertical antenna. I have assembled it, but it isn't much like any of the antennas on the Gap site, although the details are similar. It's much simpler than the present models.

    It is 10 metres long, 30 mm diameter aluminium, with a white plastic cap on the top. On insulating brackets, it has two smaller diameter elements, one 4.280 metres long, the other 2.180 metres (adjustable), each with a wire from the bottom going to the connecting screws on the gap insulator halfway up. The coaxial cable is yellow, as used by Gap.

    Does anyone recognize it? Know the bands it's good for? Should it just stand on the ground, or be clamped with insulated U-bolts??
    Last edited: Feb 24, 2009
  2. KI6USW

    KI6USW Ham Member QRZ Page

    I'll bet if you post a picture - then someone could easily identify it.
    Can you do that?
  3. ZL3GSL

    ZL3GSL Ham Member QRZ Page

    Here's a picture of it hung on a fence. The top is to the left. I'm not planning to use it like that ... it's been moved 100 miles since that was taken.
    Last edited: Feb 21, 2009
  4. KD7DS

    KD7DS Ham Member QRZ Page

    It IS an older model GAP, one of the first ones they made, but I can't recall the model name. I had one years ago, when they first appeared on the market. Early '90s? As I recall, it was advertised as 80-10 meters, possibly with only limited use on 80. It required several radials on the ground, 4, I think. If I find any info in the "old gear" files around here, I'll give you a heads-up!


    After looking at the GAP website, it appears that it was an early version of the "Challenger". The specs sound the same as the one I had. That page might be a good starting point. The manual is available for download. They might even be able to supply info for the older versions if you contact them!

    Here's the link

    73, Dave
    Last edited: Feb 22, 2009
  5. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    There wasn't any earlier version like that. The GAP Challenger DX, original model, came to market in 1993 and I was one of the very first owners.

    You're missing parts.

    It has five "elements" offset to the sides, not two, and always did have five, on the old, original model, which was the Challenger DX. As I said, you're missing parts.

    Look here for photos etc. of the way it's supposed to look:

  6. ZL3GSL

    ZL3GSL Ham Member QRZ Page

    Thanks, guys. There's no sign of any more elements being attached, so I think that's all there ever was. ;)

    I put a wrong length for the shorter element, and didn't mention that that has a nested length adjuster.

    I'll send a message to the company, and I'll put it up as it is ... it'll either work or it won't. ;)
  7. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Without more elements, I'll bet it's not a GAP.

    However, it might be a homebrew knockoff of a GAP, with fewer bands being covered. That's a good possibility.

    If it's a GAP, it should have a ~1" diameter capacitor installed in the very top of the antenna (inside the tubing, held in place by a screw) with lugs on it connecting to the yellow coax that runs down inside the antenna. That's the 80m top loading capacitor. Is that there?

  8. ZL3GSL

    ZL3GSL Ham Member QRZ Page

    It doesn't look like a homebuilt one. There is a bundle of three caps making up 2100 pf (not a single doorknob, but looking like a factory job) but the outer of the coax had broken off its connection to the element, and the centre lead was too short to reach the capacitor. I've made a short extender and reassembled it all. It will be up soon. ;)
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