Yaesu G450 or G800 Rotator, multiple VHF/UHF yagi, pole mount ?

Discussion in 'VHF/UHF - 50Mhz and Beyond' started by N3YY, Nov 17, 2021.

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  1. N3YY

    N3YY Premium Subscriber QRZ Page

    Have a Yaesu G450 rotator, pole mounted. (Not tower mounted, no thrust bearing) .
    Have the following three yagis on a 7 foot aluminum mast in the top of the rotator, all horizontal.

    33" between the 6 meter and 70cm (440) and then 4 ft between 70cm to 2 meter at the top

    Bottom 6M CA-52HB4 11 ft boom , 0.62 sq ft wind, weight 4.5 lb (just above rotator)
    Middle 440 M2 432-6W 15 ft boom, 0.85 sq ft wind, weight 5 lbs (middle)
    Top 2M M2 2m-12 20 ft boom, 1.5 sq ft wind, weight 8 lbs (at the top of mast)
    ---total wind is 3 sq ft , 17-20 lbs of antenna and coax

    Description for the G450 says "perfect for small HF beams, VHF /UHF antennas up to about 10 sq. ft.
    of tower-mounted wind load. A lesser wind load of about 5 sq. ft. can be handled when mounting the G-450ADC on top of a mast <---and this is how i'm set up

    Thinking about adding a 220 beam, not a huge one.
    This one, MSQ-22210EZ , 10 ft boom , 0.75 sq ft wind , 4 lbs .

    Does anyone have a setup like this, using a G450 rotator ?
    To do this, i'd have to replace my 7 ft mast with around a 10 foot mast .
    Yes, it's semi light, 6061 aluminum but ...10 ft is alot of leverage !
    Anyone running something like this ? Do i need to move up to the heavier G800 rotator ?
    My other option is weld up a pipe bracket that mounts to my mast below the rotator,
    goes up around it and allows me to mount a thrust bearing a few feet above the rotator.
    Fabrication and the aluminum welding is not a prob for me. Just curious if I need to do
    any of this, or will the G450 do it just fine ?

    If i keep the 7 ft mast and "squeeze all 4 antennas in, they will really be encroaching into each
    others aperature and collecting area . Am i overthinking this ?

    Please don't clog the responses with "just get another tower" or blind conjecture.
    If you are familiar with this kind of thing, I appreciate an educated guess !

    note: I have them mounted like this (6/70cm/2m) according to a pdf
    from directivesystems.com on stacking dissimilar yagi's.
     
  2. WF2Z

    WF2Z Ham Member QRZ Page

    I just mounted a G-450 on a pole. My only antennas are a Mosley A-142 14 element 2mtr. beam mounted 0ne ft. above the rotor on a 5 ft. mast going up to a Dimond X50 vertical. Yaesu says no more than a 2 and a half ft. mast using a 5 ele. 6 mtr. beam. No more than 22 lbs. total weight of antenna and mast. Just saying, seems the rotor could handle more than that as you have shown with your present set up.
     
    N3YY likes this.
  3. W2EV

    W2EV Ham Member QRZ Page

    Exceeding manufacturer recommendations is fine, as long as one realized that the "Time to Failure" is simply reduced.
     
    WA9SVD and N3YY like this.
  4. K4JDH

    K4JDH Ham Member QRZ Page

    I used all my fingers and toes while calculating the loading.
    FWIW, I have had a Yaesu "400" sitting under a Cushcraft 20/15/10 Yagi. It was very used when I got it and has been fine for over 15 years.
     
    N3YY likes this.
  5. N2SLO

    N2SLO XML Subscriber QRZ Page

    wow that's more wind load then mine. I also have the G450 right now its sitting on my deck in a 5 foot tripod with 3 antennas above : M2 9E for 144, M2 10E for 222, and K1FO 15 for 432. its all on a 5 foot mast, not ideal and antennas very close to each other but its temporary. I calculated this at my former location, all of this was on the roof on a Rohn 5 foot tripod and on a 7 foot mast. I think the wind load above 450 was like 2.5 or so. Never had a problem. I personally would not go more then 5 foot of mast above G450, unless you have a roof top tower and mount it with a thrust bearing etc but I am no expert here. good luck
     
  6. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    I'd go for the G800 series if possible.

    I've had G450s fail in portable service and although in the case described it sounds pretty easy to just swap one out (nothing very big or heavy), that's still a nuisance and more so if you need to do it in bad weather.:p

    The problems I've experienced the G450s is they have no brake, so using antennas with longer booms (like 20') can cause issues as the gearing is the only kinda-sorta brake they have.

    For anything 20' long I'd use either a rotator with an actual brake (like a HAM-IV, etc.) or a worm gear drive -- those don't need a brake.
     
  7. KD9VV

    KD9VV Ham Member QRZ Page

    I see no problem for you.
    Look at my QRZ pic. Turning it all with the 450 also atop a mast, no tower.
    5ele 6M on bottom, 9ele 2M next then a 15ele 432 on top.

    Not sure why you want the 2M on top?
    Generally, the heavier/higher wind load antenna should be on the bottom with the lightest wind load on top.
    Not just wind, but twisting torque with a heavy antenna on top is not the best way to go.
     
    N3YY likes this.
  8. N3YY

    N3YY Premium Subscriber QRZ Page

    Best compromise to keep them somewhat out of each others aperatures. 2 Meter on top, farthest away from 6M and 432 in the middle will have least affect on either. Read up on stacking dissimilar yagis. Directivesystems has some info as do others . Additionally, I would be doing the most searching on 144, hence it being on top, above trees at 90 and and 270 deg from what you see in my pics.. IF you look on my QRZ page you see that although i'm high up, i do have a ridgeline and trees hard left and hard right, with the ridge still rising about 75 ft directly behind me ...and 144 would be around 50 ft . For a 2M or 432 yagi directly above the 50 MHz elements, there is not nearly enough metal presented by the 6 meter beam elements to make a ground plane. These antennas will function normally with minimum spacings of 33" and 48" . There should be no beam uptilt on 432 or 144 MHz as a result of the close six meter beam location. The short wavelengths at 432 make the several feet spacing between 50 MHz elements appear transparent when placed below the higher frequency yagis . Thanks for commenting. I just looked at your pics . Have you considered putting your 432 in the middle and 144 up top ? You actually have more freq seperation that way, with the same spacing.
     
    Last edited: Dec 18, 2021
  9. KD9VV

    KD9VV Ham Member QRZ Page

    Yep; tried it and measured with RF field strength meter...didn't see any diff in field or pattern lobes. YMMV
     
  10. VE3TMT

    VE3TMT XML Subscriber QRZ Page

    I've had a G450-XL on the tower turning an A3S tribander and 2m beam for 13 years without a problem.
     
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