A antenna issue that has me stumped

Discussion in 'CB Radio Forum' started by craig_sez, Jul 14, 2022.

  1. craig_sez

    craig_sez Road Train Member

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    As she sits parked in front of the house..new 102" into a solid 6"riser..
     

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  3. Night Stalker10

    Night Stalker10 Road Train Member

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    Is the top picture the original antenna or the new antenna setup numbers? Those numbers are very impressive.

    Edit: Oh wait when you said bottom picture, I thought you meant the bottom picture showing the antenna.
     
  4. craig_sez

    craig_sez Road Train Member

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    The pic where you see the truck # is what i put on today...The other one is almost two yr old set up..
    #'s are not bad just to far up in the cb band....If i had the #'s i have on 40 down on or near 20 i would be happier...
    In my area the local ch is 1(26965)so i listen there the most...When i go side band its (38 lsb) and my #'s as you see are much better......
    When i had first installed the 102 on the 10" riser(bottom pic)i was getting even closer to darn near perfection,had a higher return loss(higer the # on the analyzer the better)which i think is rec..The rl also seems to have something to do with swr measurement..
     
  5. Night Stalker10

    Night Stalker10 Road Train Member

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    I understand what you are saying, I just don't think it would be that noticeable performance wise. But I could be wrong. Here is an article about return loss which is basically the reflection of light in an RF signal. This article is referring to fibre optics, but the same principle applies to coax. Hope it helps.


    What is Return Loss?
    The measurement of the amount of light reflected back toward the source is called return loss, and it is expressed in decibels (dB). This measurement parameter is always a positive number, and a high return loss is a favorable measurement parameter that generally correlates to a low insertion loss. Similarly, reflectance, which is also a measurement parameter that expresses reflection in decibels, is a negative number, and if it is excessive, it is not a favorable measurement parameter.

    Return loss is the loss of signal power due to signal reflection or return by a discontinuity in a fiber-optic link or transmission line. This impedance mismatch can be with a device inserted in the line or with the terminating load. Moreover, return loss is the relationship between both the reflection coefficient (Γ) and the standing wave ratio (SWR). Incidentally, if you increase the return loss, it will correlate to a lower SWR.

    Return loss is a measurement parameter that expresses how well a device or line matches. A high return loss is advantageous as it will result in a lower insertion loss.
     
  6. craig_sez

    craig_sez Road Train Member

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    From doin my run last night this newer set up has a bad case of cooked noodle lol....Gotta sturdy it up some more some how..Not sure if im getting any better or worse rec to be honest..Still those puerto rician fellas and some mexicans i think from down nyc area,drove me nutz yesterday when some yahoo locked his stereo on his radio and at times when the skip signal was strong it would block out all the locals that were any more than 1/2 mi apart....

    Yeah i get the idea on what you posted,i sorta knew that but thats about it..Not enough detail on it in my antenna book..

    Tks though..
     
  7. Night Stalker10

    Night Stalker10 Road Train Member

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    Your welcome, I really don't get too hung up on the theory about the return loss. I don't even know what the magical number is to look for, such as 20, 30 or maybe 40 something decibels. I just try to get the RL number as high as I can like you've mentioned before. I forgot to mention that 10 inch riser is very nice looking. The machine shop did a great job making that for you.

    I did notice that the antenna looked kind of weak with it leaning so far forward. My goofy thoughts were that you need to stand it straight up, and tie some fishing string from the top of the antenna to the front grill of the truck.. Ha.
     
  8. craig_sez

    craig_sez Road Train Member

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    The 10" one i bought off ebay from a seller who makes them stateside somewhere..
    Thats the one you see on the ground,the one i just had made and installed is the one with my truck # ....Yes the 102 is leaned about 45 deg (on the bracket)and then droopes a lil more under its own weight...With the 10" i had some stiffer pvc to stop most of the flex,not so on my latest set up..
    I got some wimpy pvc on it now but will be changeing it very soon...I only drive 58mph(for mpg)and the wind at that speed sit it straight up,so im sure to be gettin some reflect off the cab..
    I thought 25 db return loss was the best based on my aarl ant book but i have had and see others with a good bit higher #'s so thats why im trying to get better #'s..Plus i would like them clkser to ctr of the cb band like i had before..
     
  9. Ridgeline

    Ridgeline Road Train Member

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    So you are using it from the coax into the truck.

    just a thought, maybe I’m not reading this right but you need to see what the antenna is doing at the stud, not at the coax inside the truck, you are trying to determine what is wrong with a low frequency resonance.

    check the mount and take the reading right at the antenna.
     
  10. craig_sez

    craig_sez Road Train Member

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    If i have a dbl male adapter ill try it but my aa55 zoom allows that option of eliminateing coax through a load,short,open adapters..
    It still is attached to coax to do so but...
     
  11. Ridgeline

    Ridgeline Road Train Member

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    You can’t compensate for a bad feedline, it is a process of elimination.

    you may also have common mode current issues.
     
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