Need some help with my 5BTV

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by N4FMG, Apr 9, 2012.

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  1. N4FMG

    N4FMG Ham Member QRZ Page

    I finally got my vertical up, Hustler 5BTV, the antenna is obove my shop with a metal roof, Roof dimensions are 32X31 feet.
    I wasn't sure what dimension chart to use for the assembly from DX engineering, so I Used the mounted on roof with radials.
    but there are dimensions also for tower with radials, ground no radials, ground with radials.

    I used the prefered radial for metal roof instuctions with 16 radials draped over the metal roof.
    I didn't connect the antenna gnd feed point to the roof ( wasn't sure if I was supposed to )

    Is there any best method for this installation on a metal roof?
    Any idea what dimension chart I should use?
    I was thinking about reseting it to the ground mount with radial settings as my radials are not tuned length just random length.

    Also the radials are all the same length with some of them hanging off the edge of the roof.
    I was able to get 10m to tune but 15 is way off it's lowest swr is 2.0 at 19.8-- mhz, Have a antenna analyzer to tune with (MFJ 259b) the other 20 and 40 are about the same and 80 I
    have a dip at 1.4 swr at 3.7815
    Not sure what I'm doing wrong here or what I should change on the setup.
     
  2. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    I think DX Engineering has done a great job of making a very simple antenna complicated.

    The "old time" Hustler instructions for a 5BTV (liek 40 years ago) was: Put it up, add radials, adjust the tubing lengths for minimum SWR on the frequencies of choice," and that was pretty much it. They worked great, simply following those instructions.

    You tune up each band from 10m to 80m, one by one, starting with 10m. The tubing lengths all adjust a lot in length just loosening the clamps and re-tightening them. Sounds like you're way off on 15m because the tubing between the 10m and 15m traps is set too long. Change that. 80m is usually the "last" adjustment you'd make, after everything else is done, and is adjusted by the whip length above the loading coil.

    It's a really simple antenna.
     
  3. N4FMG

    N4FMG Ham Member QRZ Page

    Any ideas on the ground plane, Should I just leave the radials I have draped on the metal roof, I dont have a connection from the antenna base and the
    metal roof at them moment.
    And will the length of the radials be important?

    There was one other thing, When I'm adj for resonance should I move the trap cover up or down or adj the gap between the trap and sleeve?
     
  4. WX7G

    WX7G Ham Member QRZ Page

    I would attach the 5BTV coaxial cable shield to the metal roof. If you do use radials use two 1/4 wavelength radials per band; not all the same length.

    You will need to tune the antenna band by band starting with 10 meters. If you are unable to obtain a good enough match (1.5:1 or lower) you might have to tune a trap or two. DX Engineering has directions on how to do this. An antenna analyzer such as you have is needed. Mark the trap with a permanent marking pen so you can reset it if needed. I've tuned the traps for a ground mounted installation and it's not difficult.
     
  5. W9GB

    W9GB Ham Member QRZ Page

    Fred,

    If this is a new BTV antenna, them Leave the trap covers ALONE !!
    ADJUST the spacing between traps, as outlined in instructions.
    DO NOT cut tubing.

    Plenty of damaged BTV antennas on used market due to pilot errors.
     
  6. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    I must agree with this. In the "real" Hustler instructions they never advise to adjust the traps in any way.

    DX Engineering's instructions do. I've never had to. The traps are sealed from the inside and the moment to move the trap upper cover to adjust one, you break that seal (and Hustler stipulates this also voids the warranty). I wouldn't bother with that.

    The tubing lengths (NOT traps!! -- just the sliding aluminum tubing sections that make up the radiating element) are all adjustable, bottom to top.
     
  7. N4FMG

    N4FMG Ham Member QRZ Page

    Got up on the roof last night and reset the antenna to the settings recomended from DX Eng. They recomended using the
    ground mount with radials for my base settings. Also did some more work in the radials laind out over the metal roof and added a way
    to connect the metal roof to the feed point of the antenna base so I can try it both ways

    It got dark out before I could tune it so that will be tonights venture

    Thanks to all for the tuning info, the DX eng. insturctions are a little unclear and confusing as to what section (the trap cover or the tube below it.) to adj for your tuning.
    I'll keep everyone posted.
     
  8. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    There's nothing the slightest bit confusing about the original Hustler instructions.

    If you look at this short instruction guide, dimensions "A" adjust 10m; dimensions "B" adjust 15m; dimensions "C" adjust 20m, and dimension "D" adjusts 40m. They must be adjusted in that order: http://www.dxengineering.com/pdf/hustler_4btv5btv_instl.pdf

    None of that has anything to do with trap covers. They specifically advise:

    That's printed in bold lettering in the Hustler instructions.

    DX Engineering went on to create a 60-page "BTV" manual (!) which IMO is about 58 pages more than needed. It's a really simple antenna and there's not much to it, or to adjust. I'd never adjust the trap covers.
     
  9. KO6WB

    KO6WB Premium Subscriber QRZ Page

    You will find the radials you have will couple to the metal roof. It's sort of like you had it ground mounted with a bunch of radials. Tuning the radials is good but not necessary. The 5BTV will still work well.
    Use the instructions from Hustler and you should do well.
    Have fun
    73
    Gary
     
  10. N4FMG

    N4FMG Ham Member QRZ Page

    Ok got on the roof last night after resetting the antenna to the specs for ground mounted with radials.
    16 radials laid out over the roof and the metal roof attached at the ground feed point.
    tried it with out the radials attached and the band dip points dropped further down the bands.

    All the bands are tuning low in the band the best I can get 10m is 28.600 for its cener point.
    15 will dip around 20.700 at 1.9 swr , 20 meter dip is in the lower part of the band 1.6-1.7 swr , 40 meter is out of band on the dip as well. 80 m looks o.k it's 3.783 at the dip point at 1.3 swr.
    the gap at the 10m adj is complely closed and I cannot shorten the antenna any further,
    .

    Not really sure where to go at this point. Should I add more radials and try for tuned lengths?
    I know the bands above 10m adj point will all be off till I get 10m sorted and can go up the antenna from there.
    15m bothers me because the lowest swr I see even out of band is 1.9 to 2.0 swr.

    I'd move to the ground and but I dont have any clear area that dosen't have metal around it, all closer than 20 feet from any mounting
    position.
     
  11. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    That's perfect. Why would you think that's bad? Normally, "everybody" shoots for 28.500 as the resonant frequency for a 10m antenna, as that's a perfect compromise between CW/digital and phone bands, and might even work in the FM section above 29 MHz. I wouldn't do anything with that.


    You don't need to do anything on 10m, it's set just right. Shorten the tubing above the 10m trap so the 20.7 MHz dip comes up in frequency to about 21.2 if you can. That doesn't take much shortening. When you do that, the 20m dip will also come up in frequency, as will 40m. You might have to adjust all the tubing lengths to make them shorter, this is not uncommon. The 80m "dip" is based on the length of the whip above the 80m loading coil and it's very critical: 1/2" of movement shifts the frequency quite a bit. 3783 is a bit "low" in the band for most, but maybe that's where you want it to be. The 80m operation of a 5BTV is quite narrow band, so if it dips at 3783 it should rise to 2:1 or so at about 3758 and also at about 3803. It should rise to 3:1 or higher at about 3733 and 3833 or so. That's the way it goes, nothing you can do about that. But it is "independently" adjustable after you have the other bands set up.

    Right now, I'd do "nothing" about the 10m resonance, it's right where it should be.
    .
     
  12. N4FMG

    N4FMG Ham Member QRZ Page

    Thanks for the help, I was shooting for 29.000 10m ( might have been to high from what I'm seeing) as it would mainly be used in the ssb segment from 28.300 to 29.700
    I had a better swr curve with the roof not electricaly connected so I'll change that back and work on the rest of the bands tonight.
     
  13. W9GB

    W9GB Ham Member QRZ Page

    This is where 1/8 and 1/4 inch increments make a difference.

    1. IF you desire a higher frequency than 28.60 MHz, then the tubing length below the first trap needs adjusting (shorter). Do you operate FM in upper segment?

    2. Once that is set, then find out how much 15 meters moved up.
    The length of next tubing section (between 1st and 2nd trap) is adjusted for desired 15 meter center point.

    3. Then move on to 20 meters and 40 meters.
     
    Last edited: Apr 11, 2012
  14. AD4J

    AD4J Ham Member QRZ Page

    I would leave 10 meters as it is. Almost all the SSB I've heard on the band is from 28.300 to 28.750, with a high percentage in the 28.400 to 28.550 range.

    When you say that the SWR curve is better without a direct connection to your metal roof, do you mean the SWR stays lower over a wider range (greater bandwidth)? If so, you may want to keep the connection to the roof. Greater bandwidth is often an indicator of lower efficiency. You may have a stronger signal with the roof connection. If you have an antenna analyzer, compare the R readings at resonance with and without the roof connection. If the roof connection gives a lower R, this probable means less loss in the ground plane system.

    Jim
     
  15. K0RGR

    K0RGR Premium Subscriber QRZ Page

    I'm surprised at some of your results. As others have said, you've got 10 meters about right. I'd leave it alone.

    If you can't adjust the 15 meter segment to bring the resonance up in the band, then you may need to consider other things, but I think you should be able to adjust it. I've seen that situation myself when ground mounting one. According to DXE, the 5BTV's are shipped with the traps set for roof mounting. If you were ground mounting it, I'd be more concerned about getting it tuned and having to adjust the traps, but that should be avoided.
     
  16. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    I think unless DXE has a special arrangement with Hustler (maybe they do, I really don't know), the "traps set for roof mounting" is sure news to me. The BTV's have been on the market for a good 40 years or so without any design changes I can see, and the original Hustler instructions didn't say anything like that, and specifically warn against attempting to adjust the traps. I've installed a lot of these over the decades and never adjusted the traps on any of them.

    I adjust the tubing lengths, of course, and also the radial lengths if the antenna is elevated. Both influence resonance.
     
  17. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    The SSB segment isn't 28.300 to 29.700, really (although it would be legal to use SSB there, except for Technician Class licensees who are restricted to 28.300 to 28.500 only). Above 28.900 or so everything switches to AM, then above 29.300 everything switches to FM and all the repeaters are above 29.300 (and in the U.S., they're all above 29.600).

    You might try operating SSB up there but I doubt you'll find anyone using it, or get any answers.

    28.300 to 28.500 is where "most" SSB activity is, and it splashes up above 28.500 when the band gets busy. But rarely above 28.700 or so.
     
  18. AE5SB

    AE5SB Ham Member QRZ Page

    Read the DXE instruction book on how to turn the traps. THEN TURN THE TRAPS!!!
    I just put up a 4btv and had to do the same. 1.5 SWR or less all bands
    The metal roof should be a GREAT ground plane for your vertical, only problem is I don't have roof like yours:)
    73 & Good DX
    David AE5SB
     
  19. NL7W

    NL7W Ham Member QRZ Page

    I remember taking part in exciting activity on 28.885 MHz in decades gone by! ;) But then, I op'ed 6M and 10M with larger yagis.

    Like usual, you're right, the traps won't need to be touched whatsoever. Only Tubing lengths need to be adjusted, start adjusting lengths from 10M, or the lowest or closest to the feed point, and work your way up the antenna, band by band.

    I've so many radials under mine the lowest VSWR is 1.5 or 1.7 on most bands, indicating a lower than 25 ohm feed point impedance (except 10M, where it's relatively a "perfect" match for most of the band because of low length to width ratio and trap influence). With many radials, they do okay to good for a vertical. In fact, I talked to you on it this past Sunday.

    The Hustler "BTV" series is a tough antenna, and their prices are hard to beat.


     
    Last edited: Apr 11, 2012
  20. N4FMG

    N4FMG Ham Member QRZ Page

    I should have specified about the swr beeing better, It was higher in the band on 10m with the metal roof not being attached.
    it almost matched the curve in the DX eng book for 10m.

    I'm really new to this and if someone could give an idea where I should tune the resonant freq on the bands.
    I've got my General lic. and have been studing for my extra for a few months now.
     
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