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m-400 starduster

Discussion in 'CB Antennas' started by my2995dx, Mar 26, 2017.

  1. my2995dx

    my2995dx Member

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    Sitting here look at directions for a m-400 now what the beep want to set it for 10/11 meter says 2607mm which is 8feet now is that from the tip of the top radial to the tip of the lower radials.


     

  2. Marconi

    Marconi Usually if I can hear em' I can talk to em'.

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    show us what you are looking at.

    If it is an original it is all bolted together with screws so it is fixed as to setup, just put it together.

    If it is a Sirio M400, the only one that I think might be in production anymore, I think is fixed as to setup also, just put it together. However, I don't find it in their catalog on line anymore.

    Best I can recall the radiator is about 97" inches and the radials are 107" inches with the hub in between.
     
    #2 Marconi, Mar 26, 2017
    Last edited: Mar 26, 2017
  3. my2995dx

    my2995dx Member

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    This paper here its a repoduction not orig so then ot would be 97" for top part and 107" for the bottom 3
     

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  4. Marconi

    Marconi Usually if I can hear em' I can talk to em'.

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    If I was to guess, yes you have it right 97" top and 107" bottom.

    That looks like an old Sirio instruction. If I could read the image it would help, but just do what is says. If you can't understand the chart and how it works...let us know.

    Those Italians must only have an "L" to show dimensions, but there might be words that describe how to use their chart. I would guess that you find a frequency you won't to center on and use the chart to figure the length for L.

    L is for the radiator and L is for the radials if you can figure that out. They just don't make it easy anymore.
     
  5. Marconi

    Marconi Usually if I can hear em' I can talk to em'.

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    Just check the match before you raise the antenna up to working height and you should be good to go. Be careful with the screws. Get them tight, but don't over-do it.
     
  6. my2995dx

    my2995dx Member

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    I think they used the old instructions for the new style it says revised 10-09-2011 I'll try the 97 and 107 inchs and see how it works.But they don't tell you whats size mass where the middle part goes on guess its 2" pole.
     
  7. my2995dx

    my2995dx Member

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    Thought of putting little grease on them
     
  8. Marconi

    Marconi Usually if I can hear em' I can talk to em'.

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    The mast size you will just have to check that out. Take the hub and try some tubing or pipe until you find a size that fits snugly and you should be good to go. Don't just use any old grease on your connectors, however.

    Not a bad idea, just don't overdo it and if you can use a grease that is conductive to put at the joint for the tubing is advisable.

    This antenna design for the feed point is not too good, it can and will let water easily get into your feed line if it is up for some time. There are some possible solutions for that, and the one I use is called "Stuf" made by Cross Devices. It goes inside the coax connector where water get past the lose design of most 239 connectors, they are not water tight. Just a note.
     
  9. my2995dx

    my2995dx Member

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    I have some of that stuf my last antenna i used that and silicone tape worked great
     
  10. Marconi

    Marconi Usually if I can hear em' I can talk to em'.

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    OK!
     
  11. Needle Bender

    Needle Bender ...he thinks it's funny that I stepped in it

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    2607mm ÷ 25.4(mm/inch) = 102.63" for the radiator @ 27.2MHz

    The antenna is a center-fed 1/2 wave, so the top is a stinkin' 1/4 wave, so 234 ÷ freq. in MHz = length of a 1/4 wave (of typical tubing diameter) - in feet.

    234 ÷ 27.2 = 8.6'

    or

    103.24" without the extra unnecessary tripod, part way up the radiator.

    So if it were me, I'd set it to 102 & 5/8 inches.
     
    #11 Needle Bender, Mar 28, 2017
    Last edited: Mar 29, 2017
  12. Treeclimber 123

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    You are right sir , thank you very much you just helped me as well thanks
     
  13. Alan Blackmon

    Alan Blackmon Member

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    I have home brewed two of these star duster type antenna myself. One from a 102 inch mobile whip with adjustable tip. Used some 16 ga. insulated wire for radials. Don't recall exact lengths and all but it works pretty good both local and skip. SWR is 1:1.2 pretty much across the band. Built a second from parts from and old penetrator 500 that just wasn't working anymore. It works pretty good too for local and skip. SWR 1:1.2 also. Very happy with the star duster design. I felt the design was a quarter wave with radials but have changed my thinking that this is a half wave type antenna. The tip on this antenna is up around 30 feet. So far best local contact is 28 miles. I am using a Navaho TRC 458 with the antenna. I have the RF output adjusted down to 2.5 watts AM. Still gets out to the station at 28 miles just fine. I do have power I can turn on when needed but local talk is done at stock output. My mic is a Turner +3 which I am sure is helping my modulation.

    Hi folks this is my first posting here. I live in Boise Idaho. I have been in the CB hobby since the late 70s. Got out for awhile and then one day just decided to pick it up again about a year ago. I still use my handle from long ago. Big A. Locally guys hang out on 19 to give truckers radio checks and highway conditions when they ask. When we hear truckers talking we back off the channel and let them have it as they pass by. For SSB I go by Boise 521. You can find me pretty much anywhere for SSB but I do monitor 38l when skip is in. I will wander around to 36l on up to 40l to call out for contacts. Don't do much skip on AM. I have made some AM contacts but SSB is just so much nicer in my opinion.

    I have made some pretty good contacts both stock output and using extra power. My amp is a Cobra 250 which I am very happy with. I have a second antenna which is a half wave horizontal I made. SWR is 1:1.1 on it. Used parts and pieces from another old penetrator antenna that wasn't working either. Contacts have been Washington, California LA area and northward Santa Rosa Area. Arizona, Utah, and out to Georgia. Love the hobby. Hope maybe I can reach out to some of you one day.
     
    #13 Alan Blackmon, Apr 29, 2018
    Last edited: Apr 29, 2018
  14. Shadetree Mechanic

    Shadetree Mechanic 808 On The North Side of Dover

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    Welcome to WWDX! I have a Starduster on my garage station and I have learned a lot in my short time here.
    Chris 73s
     
  15. Alan Blackmon

    Alan Blackmon Member

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    Thanks ShadeTreeMe

    I have been reading and researching here awhile. It's good to be able to get on and discuss the hobby. My brother is has his general license and is trying to get me into that hobby. I don't have the desire to do it though. I respect amateur radio operators and all they do but I am happy where I am at. I got irons in other fires so to speak. He gets a kick out of my enjoying to build 11 meter antennas though.
     
    binrat and Shadetree Mechanic like this.

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