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Base New Imax wont tune 11m....this sucks

Discussion in 'CB Antennas' started by 357, Apr 25, 2018.

  1. ENC Pirate

    ENC Pirate Ocean One Cape Hatteras

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    I bought one of the the last ones on Amazon before they went out of stock(last 60 days), its 24 feet. I'm not sure I buy the reasoning its now 22 feet due to shipping? The antenna has basically been made forever with small changes. They may have sold some to 10 meter operators but the majority are for 11 meters. They are still all over the net at 24 feet, I could not find one at 22 feet anywhere? Very strange indeed :)


     
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  2. ENC Pirate

    ENC Pirate Ocean One Cape Hatteras

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    Road Pro website even lists it as 24feet, they need to get this together, if true and 22 feet false advertising? imaxx 2000.png
     
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  3. Marconi

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

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    How about 22' feet?

    Jeff, the models below were both done in Free Space. I did this in order to see the Average Gain (AG) results for each model.The AG helps indicate the accuracy of the model. A perfect model shows an AG = 1. See this value at the bottom of the Control Center image for each model, 1st page. In this case both models show near perfect AG results.

    Models: 1
    a. is the Imax model in Free Space that I started with. It was set at 27.205 MHz.

    b. is the same model as #1, except I used the trim chart in the Imax manual for a 24" inches cut...which indicated the resonant frequency the model should produce, 29.473 MHz in this case. This cut 24" inches off the top element, making the overall length 22' feet.

    Model: 2
    a. is the Imax Manual trim chart.
     

    Attached Files:

    #228 Marconi, Jan 14, 2020
    Last edited: Jan 14, 2020
  4. Marconi

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

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    Here are the Imax models set over Real Earth at 36' feet.

    Model:
    1. is the Original Imax at 27.2 MHz over Real Earth.

    2. is the 24" shortened model at 29.7 MHz over Real Earth.

    The shortened 10 meter Imax shows a bit of improvement in pattern, match, gain, and angle lower by 1* degree near the horizon.
     

    Attached Files:

  5. HomerBB

    HomerBB Sr. Member

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    Marconi, how does your model software show the shorter 22' IMAX behavior at 27.2?
     
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  6. AudioShockwav

    AudioShockwav Extraterrestrial Admin
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    Thank you for your hard work Eddie

    So basically it looks like they shortened the antenna, be it for shipping reasons or what ever and it has just moved the sweet spot up in frequency.
    Interesting that it shows a little better pattern with the short version.
    For the ham guys using it as a multi band antenna with a tuner it looks like no problem.
    But for the CB user one is going to have to put up with a increase in SWR over what was seen in the past.
    Interesting.

    73
    Jeff
     
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  7. Marconi

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

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    Homer, my short Imax scanned at 27.2 Mhz in the PDF file below.
     

    Attached Files:

    #232 Marconi, Jan 15, 2020
    Last edited: Jan 16, 2020
    Shadetree Mechanic and HomerBB like this.
  8. Marconi

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

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    If you look back at the Imax Manual for shortening the antenna 24" inches...the model will show the same results.

    To me they just shortened the antenna to suit the Ham operators and satisfy the shipping restrictions. Apparently, after they did that...they needed another 1/4" shorter. If Road Pro bought Solarcon it was probably a good distribution and marketing deal for Solarcon.

    I don't see the multiband effects I've seen with some of my previous Imax models. So, I'm curious what effect this has...and only real world testing will tell.

    I would also like to know what the new element dimension distribution is.

    If anybody has a copy of the Original Imax Manual I would like a copy. If anybody has a New shorter Imax and it came with a manual...I would like a copy for that too.
     
  9. Recon

    Recon NY 881

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    Hey guys / gals, look what I found posted on Copper Electronics Forum.

    Posted on Thursday, August 30, 2007 - 12:59 pm: [​IMG] [​IMG] [​IMG]
    Ok. It looks like I have found about 10 people with Max 2000's that resonate at 27.800 or there abouts. I found many many more that resonate at CH20. I went to a friends house and checked his.. 1.1 on CH20 with an equal curve. His antenna is years old.. Not sure how hold but one of the originals. Something must have changed inside the antenna to cause this. I agree the antenna works. I just wish it would work better on 26.9150 which is the AM call channel I use. The SWR is 2.4 down there. My johnson Viking Valiant could care less. It has a tuner built in and can tune on a piece of wire..LOL.. But my Solid state base stations and mobiles are unhappy. I Guess its antenna tuner time for me.

    The biggest thing that gets me on this deal is I spoke with Charlie at Solarcon. This man designed this antenna. He claims this antenna should be centered on CH20 and if its not something is WRONG. He is very strong about this... He said that if the antenna resonates anywhere other then the center of the CB band, something is not setup right PERIOD. In fact he claims that the antenna wont tune flat at 27.800 because of its design.

    So now I have the man that designed it telling me something is wrong and owners of the antenna saying its working as designed.... hmmm.

    Thanks a lot for all the help guys!
     
  10. AudioShockwav

    AudioShockwav Extraterrestrial Admin
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    How long ago did you talk to Charlie?
    As you can see Road Pro now makes these antennas.


    73
    Jeff
     
  11. Recon

    Recon NY 881

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    I did not talk with Charlie.
    I copied and pasted a post from Coppers Electronics Forum from 30 August 2007. There is a pile of discussions, issues and complaints relating to the 2000 going way back to 2007.
     
  12. AudioShockwav

    AudioShockwav Extraterrestrial Admin
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    Ok, copy copy.
    I did not realise that it was part of the copy and paste.
    I wish we could contact this Carlie now.
    I can't find any info that pins down a date when they antenna dropped to 23 feet on length.
    Thanks.
    73
    Jeff
     
  13. Recon

    Recon NY 881

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    Allow me to change the subject for a few minutes.
    How many guys /gals remember "many" years ago (maybe late 70's early 80's?) when full size Pontiac sedans were being manufactured and delivered to dealerships with Chevrolet engines?
    Wow, was that ever a mess-up...or was it? When a prospective Pontiac buyer opened the hood at the dealership and had seen the orange Chevy engine with orange Chevrolet valve covers, all h*** broke loose and that was deal-breaker for sure! The color of the Pontiac engines were blue. There were many owners who did not open the hood prior to signing the documents and they had taken delivery of the car. You can imagine the shock they had when they opened the hood a few days or weeks later. General Motors gave the Pontiac owners two options. Dealership to order a Pontiac engine to replace the Chevy engine, or accept a monetary refund and keep the Chevy engine. Solaron and the new owners knew about the shorter antennas and did not inform their suppliers and the public. I call that a FOUL and they should some-how, some-way reimburse the guys who are having issues with the new and shorter antennas.
     
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  14. Marconi

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

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    Recon, I posted to the thread that you referenced from Coppers. I'm surprised that you were able to find that old thread. Here is the link that does not look to require one to login.

    http://www.copperelectronics.com/discus4/messages/34/101438.html?1189328843#


    In my Bandwidth testing back in 2009 below in the PDF file...I tested my Imax at 25' to the feed point and 49' feet to the tip. Sorry this old hand written report that is not real clear. Pencil lead just doesn't hold up over the years in a folder. You can use the Zoom Feature in the PDF file I posted below if you need a closer look.Sorry the chart is not viewed in Portrait mode. You can print it out with the PDF file feature and see if it is readable.

    This test was done with a working feed line, 3' jumper, antenna switch, and my Daiwa CN801 Meter using a Kenwood TX50, so I could see more bandwidth than just the CB band. Not the best way to test, but it is what I did back then. This report only covers about 91 channels from 25.705 to 29.305 MHz showing 3.60 MHz bandwidth. This is twice as wide a the CB band and we don't see in my chart the low frequency over 1.40 SWR.

    Based on all this I'm guessing this Imax scan would show a bandwidth <2.00:1 SWR at or near >5 MHz and some of that could be as low as 1.40 SWR if I had continued to go lower in frequency.

    I remember something about AZBoatanchor, but I will not comment further. It was a long time ago.
     

    Attached Files:

    #239 Marconi, Jan 16, 2020
    Last edited: Jan 16, 2020
    357 likes this.
  15. Marconi

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

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    Another tidbit of information on the Imax.

    In the PDF file below, I stripped all the features for matching, radials, etc so we can see what happens with performance results.

    I post the Imax Manual Specifications showing gain* = 5.1 dbi.

    My Imax model when I removed the radials, the matching device, and the capacitor near the middle of the center element.

    Compare this model's gain* = 5.13 dbi vs. the gain reported by Solarcon shown above.

    Here is a similar pattern of a modeling image by W8JI you may have seen before. The link to my model of this Imax is in the PDF file below.

    [​IMG]
     

    Attached Files:

    #240 Marconi, Jan 16, 2020
    Last edited: Jan 17, 2020
    357 likes this.

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