I need advice on this vertical antenna

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by K1ZNE, Jun 2, 2020.

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  1. K1ZNE

    K1ZNE Ham Member QRZ Page

    Hello. Since my back yard is very small, i was considering a vertical multiband antenna and found this one on ebay:

    https://www.ebay.com/itm/Ham-Radio-...78&brand=Sigma&_trksid=p2060778.c100290.m3507

    Then I looked for reviews on it and although some persons said it worked fine, others said that such antenna is no more than a radiating "dummy load" that yielded ok SWR readings but a very low efficiency. I would like to hear your opinions on it! Thank you in advance.
     
  2. N1LOU

    N1LOU XML Subscriber QRZ Page

    I am not a fan of any of these end fed antennas matched with a transformer. They may present a match to your radio because of the unun, but that doesn't mean you are going to radiate signal well. It really can't radiate well without some kind of RF ground for the radio waves to "push off" from. If the vertical element is a half wave element you really don't need much of an RF ground. But for all other bands these antennas become very inefficient. If it were me I would look into a DX commander. If your back yard is super small, you can partially compensate for that by using as many shortened radials as you can fit. once you get over 30-60 radials, the length of the ground radials starts to matter much less.

    https://www.m0mcx.co.uk/store/products/dx-commander-premium-build-hf-multi-band-vertical-system/
     
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  3. K7TRF

    K7TRF Premium Subscriber QRZ Page

    They're selling a 20' pole with a 6:1 UNUN at the base and calling it a no-radial 80m-6m antenna....

    Run away...
     
    AC0OB, WN1MB, N1LOU and 5 others like this.
  4. W1VT

    W1VT Ham Member QRZ Page

    I would suggest some sort of Inverted-L. Yes, it is a compromise but in your situation a compromise is required.
     
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  5. N2HUN

    N2HUN Ham Member QRZ Page

    Well the fact that it supposedly does not need a counterpoise is a reason for caution. I've used verticals for 40+ years as a ham and always had radials as part of the antenna system. You also need an automatic antenna tuner as per their description so add that to the price if you don't already have one. I imagine though that you can use a manual tuner too.

    Also, since you are in the USA, why not check ham radio vendors and manufacturers here? There are plenty of places to buy vertical antennas and some offer free shipping too. Check Universal Radio, Ham Radio Outlet, Gigaparts, DXEngineering, to name a few, for a comparable antenna. There's plenty to choose from. In the past I've used Cushcraft, S9, HyGain and homebrew verticals.

    Well hope this help and good luck with your search.
     
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  6. VA3QY

    VA3QY Ham Member QRZ Page

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  7. AJ5J

    AJ5J Ham Member QRZ Page

    Note that this ebay seller has already had 271 suckers come his way; don't be #272...;)
     
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  8. AJ5J

    AJ5J Ham Member QRZ Page

    You could build a multi-band fan vertical for less than $50 using wire, fiberglass pole and spacers and a few bits of hardware, but if you must buy ready-made I'd suggest M0MCX's DX Commander for roughly the same amount as the fancy ebay dummy load. Check out some eham reviews here:
    https://www.eham.net/reviews/view-product?id=13524

    Ground-mounted you could easily get good performance with plenty (30-60) of SHORT radials, too---whatever will fit in your small space should be fine. They can all be different lengths as well as be added a few at a time if that helps, too. More radials=better overall performance, especially on receive.

    One other purchase to consider if you don't already have is any edition of the ARRL Antenna Book; lots of solid basic info about antennas and how they operate. Remember, there's no free lunch with antennas, and if radial-less verticals* appear too good to be true, well...

    *(vertical dipoles excepted, of course)

    Good luck with your challenging location and I hope you become a happy camper soon.

    73,

    Jeff
     
    Last edited: Jun 2, 2020
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  9. VA3QY

    VA3QY Ham Member QRZ Page

    Well put.
     
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  10. KI8DJ

    KI8DJ Ham Member QRZ Page

    Those type of antennas work best elevated as the coax is the counterpoise and it radiates too. 30 feet is the typical height suggested.

    They do work ok if simplicity is your goal. I had a Jetstream jtv 680 and worked pretty well on 20 meters and up. I managed to work the gulf coast on 40 ssb with a 100 watts from the UP of Michigan.
     
    Last edited: Jun 2, 2020

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