Bypassing Volvo multiplexer system

Discussion in 'CB Radio Forum' started by Trucker2211, Oct 14, 2016.

  1. Trucker2211

    Trucker2211 Light Load Member

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    Ok I've read a bunch of threads on here about the Volvo multiplexer antenna system but still have some questions. First off, I have a 2015 Volvo VNL 630 midroof with no top fairing (12'3" tall) and it had a single antenna on the drivers side mirror from the factory (got this truck brand new). I hooked up my Cobra 29 LX and had very crappy reception and SWR of about 2:1. I removed factory antenna and put on my 4' firestick. My reception for CB improved dramatically and still have good AM/FM too but could not get SWR down below 2:1 no matter what. This was all before I even knew about this Multiplexer system. So my question is; Can I bypass the multiplexer box and just use the factory antenna mount? Would this be a direct connection then? Or would mounting a new Wilson, k40, or even a big whip for example to the back of my truck behind the cab be better? I can have the antenna sticking up about a foot past the top of cab. I do not care about AM/FM radio since I never listen to it anyways. Thanks!
     
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  3. d281833

    d281833 Heavy Load Member

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    On mine I just ran a new coax through to a bird mount, it's a pain in the arse trying to run cable to the factory mount through the headliner,door and mirror not to mention you have to remove the connector and reconnect to feed it through, and that in itself is a whole can of worms. This multiplexer system might be good on paper but it sucks, just my opinion.
     
  4. Trucker2211

    Trucker2211 Light Load Member

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    Yeah I agree this system sucks. I don't know why in the world they would want to combine 2 or 3 different radio systems into one. What's wrong with the good ole am/fm antenna on the cowl or on top of the cab and then a mount straight for the CB radio. #### engineers! Anyways I thought about getting the perch mount and running my own coax straight to my radio but I don't see any easy way of doing this and making it look good at the same time. I have the overhead CB mount and don't want a wad of coax cable strung from the top of the ceiling down the windshield and out the door. Not only would it look goofy but I'm afraid it will get pinched opening and closing the door. That's why I was thinking about just using the factory mount on top of the mirror and using the factory wiring, unscrewing both sections of coax (antenna to box & CB to box) from the multiplexer box unit and just connecting them straight up so I just have one straight shot from radio to the factory antenna mount. I know I would lose my AM/FM radio but I don't really care. Maybe I could even run a little cheap dash mount antenna for the AM/FM radio if I really wanted to. I just hate having this system limit my CB equipment just because Volvo thinks it's cool for everything to use one antenna source
     
  5. Trucker2211

    Trucker2211 Light Load Member

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    Well I took off my lower dash panel so I could have access to the multiplexer box and well, first of all, I'm pretty sure they built this truck around this little box. It is crammed up into this little corner that is really hard to get to without disassembling half of the dash. Second, there is no easy way to directly bypass this box. The coax coming down from the CB and the AM/FM radio are hardwired into the back of it. The antenna output wire has a threaded male connector about 2 ft. from the box that screws into the female end of the cable coming from the factory mirror mount. Some genius at Volvo thought it was a good idea to wad up all of the extra coax cable with the metal connector facing towards the front and tape it against the metal firewall. So yeah, my problem was a grounded coax from the very beginning. I put on my factory 3' multiband antenna with a Wilson spring and bam! SWR of 1.2:1 on channels 1, 20, and 40, putting out 3.5W and gets great reception for a bone stock setup. AM/FM signal was improved as well. I still would like to have a big power standalone system one day, but this will work fine for now
     
  6. En5287

    En5287 Bobtail Member

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    Jul 1, 2019
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    Trucker 2211 where exactly is that multiplexer located? Is it on the left or right side of the steering wheel, on the firewall? I'm trying to run new cable as well and first of all, I had no idea the multiplexer existed until today. I bought new Wilson coax and fed it through the mirror. That was the easy part, once I fed it through the frame of the truck I was able to pick where the cable was inside the truck. I had to cut the the old male connector because it wouldn't unscrew. So I would like to use the original setup if possible!
     
  7. d281833

    d281833 Heavy Load Member

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    It's up under the dash towards the fire wall a bit left of center. It's an abomination of a system to say the least.
     
  8. Midwest_Waldo

    Midwest_Waldo Bobtail Member

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    Sep 10, 2021
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    Hey guys.. very new on here but also would like advice on volvo set up. I just bought a ranger rci39vhp and will be getting it professionally installed in cb shop. My question is through a bird perch one antenna system. What antenna I should get.. Wilson's are everywhere but seem to have my mind on a hustler whip... just seems better quality to me but I can only do so much research on you tube. Thanks
     
  9. Night Stalker10

    Night Stalker10 Road Train Member

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    I think it would be interesting to try the hustler HQ27 55 inch antenna. I ran the 48 inch version for many years on the Pete I use to drive. They are very durable and easy to tune antennas.
     
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