HF Multiband vertical antenna

Discussion in 'Ham Radio Discussions' started by K2ICC, Dec 27, 2020.

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  1. K2ICC

    K2ICC Ham Member QRZ Page

    I am looking for recommendations of an HF vertical antenna for bands from 160-6 meters or at least 80-6 meters. Using a 49:1 transformer with 134' of wire and plan to add a tuner to it. For the vertical, I am looking for a recommendation. Thanks.
     
  2. K0UO

    K0UO Platinum Subscriber Platinum Subscriber QRZ Page

  3. VA3QY

    VA3QY Ham Member QRZ Page

    No need for transformer. If you use 2 quarterwaves - 80/40m wire verticals - put up 40 exact vertical; then the 80 as inverted L; you will get 80, 40, 17, 15, 10 without using tuner. For 20m, you may add another quartwave element.

    I just hung mine to the side of the tower with a pole extension at top of tower. You can use a 11m lightweight pole too. For radials;l put in 8 underground wires (aluminium) with legnth of 11m each.
     
  4. K2ICC

    K2ICC Ham Member QRZ Page

    My 134' of AWG14 wire was doing great on 40,20, 17, 15, 12 and 10. 6 at 53Mhz. now, very low end on 80 meters, so thought about a tuner. Using a capacitor from 250 pf to 500 pf in the middle of the wire, will leave all bands intact, but raise the 80 meters to the upper end of the band. I did that, and it worked, but lost three other bands that were nice. So, will not use the capacitor, just plain wire. I believe with the 49:1 transformer, when eliminated by a relay, then ground the wire with no transformer or unun, will do 160, 60 and 6 meters.

    My goal is just 160 to 6 if possible. So, wondering if any others are using the same 49:1 transformer, and what length of wire and coax and what bands are working for them, if tuner or not. I my case, the lazt 3:1 max SWR IC-7300 internal tuner, can tune my wire to perfect SWR at 134' length, with no need of internal tuner on most bands, but using internal will get the perfect SWR. Tanks a lot for the input on this.
     
  5. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Well, a vertical is different unless you have some way to support a 134' tall vertical.

    Way different properties, and on some bands a vertical may easily outperform your wire antenna.

    But this depends a lot on where you can install it, and how much room you have "around" it. Adding 160m to a short vertical ("short" being anything less than about 65' tall) is a real challenge and would normally involve adding "loading" for 160m that needs to be bypassed for the higher bands.

    Also, a "short" vertical will have limited operating bandwidth on 80 meters; usually you'd need to tune it for a narrow section of the band (like "CW," 3500 to 3550, or "phone" at maybe 3700-3750 or 3750-3800, something like that) and a huge mismatch can occur (VSWR >10:1) if you depart far from where it's tuned.

    But anyway, there are some "80-6m" verticals in the 26-32' tall or so range that can work well on 40m and "up" and over a slice of 80m. For a ground-mounted installation, the GAP Challenger DX-9 or whatever they call it today isn't bad and only requires three 25' long radials to load up pretty well on a lot of bands; being center-fed, it doesn't need a more conventional and large radial system. The 3 radials are really just base loading.

    A 43' tall untrapped vertical with a unun and remote tuner installed at its base, and lots of radials, can also work a lot of bands and these are commercially sold by a few manufacturers. But they really do need the remote tuner, which adds cost and of course if it's outside must be weatherproof.
     
  6. K2ICC

    K2ICC Ham Member QRZ Page

    The wire is set up as an inverted L. The vertical multiband is another option I want to add up to my existing wire antenna. I called some vendors, and it seems to me, homebrew, MFJ or any other, need a a tuner, a matching network, or the combination of all or some. For example, the MFJ-2990, uses the MFJ-2910 for bands such as the 160 and 80 as an optional device, and also uses a tuner and radials. In some cases, the best thing is to mount as shown in the model stated the matching network below the antenna. In the case of the tuner, also an external weather proof tuner. The reason of the question for those using verticals. Wondering what is working for them as verticals, before I buy or build.

    MFJ for example uses a simple radial kit already made, while others needs more than one 45 or 100 radials for example. So, for my land, looking for the best option. Thanks.
     
  7. N6TDG

    N6TDG Ham Member QRZ Page

    DX Commander Classic. 40-10m with 80m as inverted L. Works well. Small space required. Portable.
    http://m0mcx.co.uk
     
    K2ICC likes this.
  8. K0RGR

    K0RGR Premium Subscriber QRZ Page

    I have the MFJ 2990, and it works great on 60 meters and up, poorly on 80, and very poorly on 160. The problems on 80 and 160 are due mostly to increased coax losses due to high SWR. On most bands, the SWR is 3:1, easily handled by most internal tuners. On 80 it's about 5:1, and on 160 it's higher. I don't have the optional 80/160 kit. I think the MFJ 2910 would be a good idea, or, better yet, a remote autotuner at the base of the antenna. I feed mine with low loss LMR400DB cable, which will make a difference.

    I'll also add that it's a great antenna for 40, 30, and 20. But when you go higher than 20 meters, it starts actually getting too long, with more radiation straight up on the highest bands.

    I have approx. 20 radials of different lengths. MFJ suggests making them all 43'. Half of mine are that size, and I have a few longer and shorter than that.
     
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  9. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    80m is a problem band with most antennas, even a full-length (1/2-WL) dipole. 5:1 is pretty typical at band edges if you tune for the center of the band; "shortened" antennas will get much worse than that!

    I use a trapped inverted vee which is about 150' long, and use it on 40-80-160. On 40m, it's full-sized and covers the whole band fine; on 80m, it's somewhat loaded by the 40m traps so it has about 90 or 95' of "radiator" and if tuned for band center, the edges are more like 10:1, possibly a bit worse. On 160m, it's very shortened by the 40m & 80m traps and I have it tuned for 1830. At 1800, it's 3:1 and at 1860 it's 3:1, or slightly worse. Above 1900, it can be nearly 10:1 and at 1990 the SWR is so high I can't even define what it is!

    Such are the problems with any kind of "shortened" antenna that doesn't use special compensating circuits, or designed-in resistive loss.:(

    Still, better than nothing! I've worked >100 entities on 80m with it, and about 40 on 160m, without trying terribly hard (mostly CW).
     
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  10. AE1N

    AE1N Ham Member QRZ Page

    I have a 43 foot vertical with 4 elevated 25' radials and a AUTOMATIC TUNER from MFJ. So I load up and work all 11 bands (6 meters through 160 meters) Instant band change... what could be simpler?

    H vs V 80-160m_cr (2020_11_06 06_40_22 UTC).jpg


    Radials or NO Radials_cr (2020_11_06 06_40_22 UTC).jpg


    Vert Antenna Height_cr (2020_11_06 06_40_22 UTC).jpg


    ---Layne AE1N
     

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