Antenna Input Right-angle Connector

Discussion in 'CB Radio Forum' started by Tumbleweed TowMan, Jun 24, 2022.

  1. Tumbleweed TowMan

    Tumbleweed TowMan Light Load Member

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    Jun 22, 2022
    36°06'28"N 109°21'04"W
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    Hi,

    I run a new Freightliner M2-106, with twins on the mirrors, and the unit in the overhead console cubby. I am quite good at any type of installation, but very novice to the parameters of CB tuning - I learn as I go.

    I am using a co-phase cable to the unit, but the unit is a Cobra 29 Classic, kindly bulky. I am using a right-angle connector from the co-phase into the unit due to the depth being restrictive. I am getting 1.2 swr all the way across, have done a radio check at the yard with another wrecker, he said it sounds ok.

    My question is, would my setup be even better if I negate the right-angle connector?

    I wanted to do that at the moment of the current installation, which would be a hole directly behind the unit (lots of open area in the cab roof area), but it's a wrecker that I run, so when the phone rings, all the hoo-hah in this pic is what I had to jumble up to hit the road! ugh.

    [​IMG]

    Thanks, keep the rubber on the road!

    Tumbleweed
     
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  3. Night Stalker10

    Night Stalker10 Road Train Member

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    Jun 26, 2017
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    In an ideal world, the less connectors in your antenna system the better. When you have problems with your antenna, it's makes it easier to troubleshoot with less connectors. But in the real world, you have to do what works. Over the years I've used the 90 degree connectors when I had no choice, and it caused no issues with my antenna system (if your antenna is installed correctly), plus it's the CB band.
    You say you have an SWR of 1.2 over all 40 channels (at least I assume that's what you meant by all the way across), that sends up a red flag for me. Please don't tell me that you are using the SWR meter in the Cobra radio. They are junk, you need to use an external SWR meter in order to get a more accurate reading.
     
  4. Tumbleweed TowMan

    Tumbleweed TowMan Light Load Member

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    Jun 22, 2022
    36°06'28"N 109°21'04"W
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    Hey thanks for the reply.

    Yes, it is the built-in, and yes I do recognize it as reference only (using that was part of "gotta go now!", have not got back to the project yet). I have a Workman, and the built-in was very close to that. However, this install is the new truck, and that last swr read was on a single antenna setup.

    What is the red flag?
    Again, I am learning this as I go, so thanks in advance for any tips.

    FYI ..... the ants are Tram 4' steel bottom load, with added recoil spring.

    Tumbleweed
     
  5. Ridgeline

    Ridgeline Road Train Member

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    No, it would not be.

    it would be better to rid the dual antennas and go with a single one.

    m2 (class 7) isnt bad to setup a good rig, lots of metal to work with but it is smaller than a cascadia or other class 8 trucks, so phased antennas don’t preform well.

    that said here is the important advice, if it works … LEAVE IT ALONE!
     
  6. Tumbleweed TowMan

    Tumbleweed TowMan Light Load Member

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    Jun 22, 2022
    36°06'28"N 109°21'04"W
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    There isn't anywhere for a centered single without drilling a hole in the fiberglass roof (only the outer ridge cap being metal), boss does not want that, worried about factory warranty on his new custom truck (Freightliner is usless for finding out a particular "will this void it).

    The rest ofthe vehicle is a rollback.
     
  7. Ridgeline

    Ridgeline Road Train Member

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    Who said center?

    just use one mirror mount but again if it works, leave it alone.

    the only way the warranty is voided is if you don’t do maintaince, it’s not a car … it is a commercial vehicle.
     
  8. Tumbleweed TowMan

    Tumbleweed TowMan Light Load Member

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    Jun 22, 2022
    36°06'28"N 109°21'04"W
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    > The ponder of right-angle would still exist.

    > It isn't my $135K truck's warranty, that's the call of its owner.
     
  9. Night Stalker10

    Night Stalker10 Road Train Member

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    Jun 26, 2017
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    Thanks for the info on your antenna. The red flag statement was about your antenna having a low 1.2 swr across all 40 channels. Most of the time when you adjust the antenna on a big truck (I like to use channel 20), for lowest swr reading, the readings on channel 1 or channel 40, will usually be higher or lower than channel 20. There are many factors that causes this, such as antenna bandwidth, efficiency, and RF ground. Also antenna design such as coil position, bottom, middle, or top. Antennas like your Tram which uses the bottom load coil, is the least efficient compared to mid or top loaded antennas. Now since a cb radio has 40 different frequencies (40 channels), you need an antenna that's broad banded in order to cover them all. The problem is that an antenna that's too broad banded can suffer in performance (efficiency) which isn't good. So I hope this helps you to understand that a low swr reading across all 40 channels isn't necessarily a good thing.

    On a side note, a really good antenna is the 7 foot sharpshooter. It doesn't have a coil, and yet it's a decent broad band antenna with a very high 96% efficiency rating. Some guys on this forum use these antennas on their trucks with very good results.
     
  10. Tumbleweed TowMan

    Tumbleweed TowMan Light Load Member

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    Jun 22, 2022
    36°06'28"N 109°21'04"W
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    Well that figgers! lol

    In the next few days I'm going to go ahead and pop a hole to run the straight plug, just because I'm persnickety.

    Will grab an open lot and put the Workman meter on it, and come back to this thread.

    Thanks for the info fellers!

    Tumbleweed
     
  11. Naptown Muduck

    Naptown Muduck Light Load Member

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    Jul 30, 2018
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    There’s no advantage to drilling a hole in the center of a fiberglass roof. You need the antenna mounted tometal to get an rf ground. Use the mirror mount
     
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