CB and GMRS radios sharing mounts & mics (not antennas)

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Flagtop

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New to overlanding and offroading, and now tackling comms. I bought both types of radios. Now figuring out what goes where.

I'm thinking if I'd only need one type of radio at a time (true? false?) then I could:

Mount both radios side by side
They could share an antenna mount
They could share a mic

Kind of feels like it could simplify the look/install/etc of everything. Thanks in advance for any opinions!

2020-11-29 11.03.09.jpg
 
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M Rose

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New to overlanding and offroading, and now tackling comms. I bought both types of radios. Now figuring out what goes where.

I'm thinking if I'd only need one type of radio at a time (true? false?) then I could:

Mount both radios side by side
They could share an antenna mount
They could share a mic

Kind of feels like it could simplify the look/install/etc of everything. Thanks in advance for any opinions!

View attachment 179052
To share the antenna mount you will need a bulky coax switch to select between GMRS and CB.
GMRS radios and CBs use two completely different kinds of mic connectors, and without a serious amount of research, wiring, and trial and error it’s not going to happen... Mics vary by manufacturers and by radios themselves... my Cobra 15 mic won’t work with my Galaxy 959 (both are CB 4 pin mics)- also I can’t use my Icom mic with my Yasue Radio without an adapter and a converter... and the Icom/ Yasue mics won’t work with any of my CBs.
 

RoarinRow

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Personally, I would keep two separate antenna mounts. The antenna that came with my Midland MTX115 is only a couple of inches tall so it's not really an eye sore. For my CB radio, however, my Firestik antenna is closer to 4' tall including the spring base attachment. As far as repurposing between units, I think it would more of an inconvenience to remember to swap the two. Plus, there might be occasions where you want to run both at the same time. Some members of your caravan could be on either/or units.

My .02.
 

Ubiety

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I'm thinking if I'd only need one type of radio at a time (true? false?) then I could:
That is probably true, but who knows what others are doing. If you have a group that you intend to go out with find out what they use and use what they use.

They could share an antenna mount
Maybe, probably not. Antenna mounts have different styles of "antenna connectors" and in my experience CB is different from GMRS or Ham - but your mileage may vary. Not sure that this would be an issue but the antenna coax needed might be different between different radio styles. Again, not sure on that one.
 
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Ubiety

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Personally, I would keep two separate antenna mounts. The antenna that came with my Midland MTX115 is only a couple of inches tall so it's not really an eye sore. For my CB radio, however, my Firestik antenna is closer to 4' tall including the spring base attachment. As far as repurposing between units, I think it would more of an inconvenience to remember to swap the two. Plus, there might be occasions where you want to run both at the same time. Some members of your caravan could be on either/or units.

My .02.
Important point about what @RoarinRow said about forgetting what radio was connected to the antenna. Transmitting without an antenna is a good way to fry a radio. Some have built in circuitry to protect you from this others do not. Generally it is taboo to run/TX without an antenna. Separate antennas would get rid of this concern for you.
 

M Rose

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That is probably true, but who knows what others are doing. If you have a group that you intend to go out with find out what they use and use what they use.


Maybe, probably not. Antenna mounts have different styles of "antenna connectors" and in my experience CB is different from GMRS or Ham - but your mileage may vary. Not sure that this would be an issue but the antenna coax needed might be different between different radio styles. Again, not sure on that one.
Both CB and GMRS use RG-58 50 ohm coax, and you can get an NMO mount CB antenna... so that part does work... but that would be the only part of his idea that would be doable.

Even though they both share the same kind of Coax. They do not share the same kind of Coax Connectors. CB uses a PL-259 while the GMRS uses a SMA connector. You can make adapters, but like Greg points out, forget which antenna is hooked up and key the wrong Mike, bye bye radio... especially the CB as they don’t have SWR protection circuits... some GMRS radios have the built in protection circuit. But not all.
 

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Great stuff guys, thanks so much. I'll go with two separate antennas. For mics, if they happen to work out then great, but otherwise I'll use two there also. Can just try and see. (And I won't expect much) :smiley:
 

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Sounds more complicated than it has to needed. What are both types of radios?

I'm running CB, GMRS HAM and a cell booster.
Cell booster: Weboost drive reach (installed, that's the one up top) with the Wilson truck antenna

GMRS: Midland MXT400 (finishing install today) with the ghost 3d and longer 6db antenna (ghost for city and longer for trail)

CB: Uniden PRO505XL with the FireStik FL3-B 3' FireFly antenna

I'm excited about the GMRS, and the CB is mostly so that I don't miss out if that's what the group is using...
 

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The Uniden Pro505XL mic is only interchangeable with the other Uniden 5XXX mics stock out of the box... rewireing them for use as a Cobra or other brand of mic is possible, but the. They don’t work as a Uniden any more... If you figure out a way to do this... DO NoT Post a How To... File a patent and sell it... seriously...
 

Prerunner1982

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Just to muddy the waters just a little bit.. :smilingimp:
There is an antenna that might work for both radios, it's a 4 band antenna that covers 10m/6m/2m/70cm. 10m is close to CB, and 70cm is close to GMRS.. Is it widebanded enough to tune the adjacent frequencies that you need? I don't know. Would it work well if it could tune to those frequencies? Probably not on CB but would work fine for GMRS. Is it worth the price to experiment with? That's your call, but sometimes to get what you want you have to experiment with...and sometimes it doesn't work.
You could certainly connect the radios to use one mic, pic out for the CB is easily found....pinout for the GMRS radio not so much. Unlike a ham radio manual, the GMRS manual does not include the mic pinout info.
There are companies such as Stryker that make adapters to go from a RJ45 mic to a 4 pin mic so it can certainly be reversed.
You would need a switch for the mic and a switch for the antenna and you would not be able to use the radios at the same time, even to monitor as one radio would not be connected to the antenna.
To at least be able to listen to the other radio that you are not using you would replace the antenna switch with a Duplexer, you could use either radio without having to remember to switch the antenna to that radio. But you would still need a switch for the mic.
 
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Flagtop

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Why you gotta muddy the waters? All was so clear! hahah

I have a scanner (doesn't transmit) that could listen for the other radio I guess, but seems simpler to just have the two. I'd hate to nuke a radio by transmitting without an antenna.

Update! Got the GMRS all setup today (ghost antenna). CB is ordered and shipping sometime, so won't have that one this weekend.

2020-12-03 16.22.37.jpg
 

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Just install both radios and two separate antennas. I have a primary radio spot and a "secondary" radio spot. THe secondary spot is typically setup for a basic APRS setup but I can easily throw in my CB radio as well. I run a NMO mount on each fender. The passenger side one is either a 1/4 wave VHF for APRS or a NMO CB antenna. A Browning BR140 antenna.

As far as the different gain antennas. You may actually find the 3db antenna to be more effective off pavement. The higher the gain the more the signal is "pinched" towards the horizon where as a lower gain antenna can provide a more "round" radiation pattern. This means in an off pavement situation where the group is spread out by distance AND altitude the higher gain antennas may be firing your signal straight into a mtn side where the 3db antenna will project the signal "up" and "down" better. This also has the advantage of the shorter lower gain antennas being less susceptible to getting ripped off by foliage.

 

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If I were to run a base camp 20ch raido and a CB radio in my rig, would the antennas interfere with each other, and if I'm asking in the wrong spot I apologize
You will be fine.
 

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Why would you want to use both a CB and GMRS? I thought that the CB radio is pretty short range and has a lot of interference. Sorry if pretty offtopic. I was thinking only going with GMRS, when I get to that point.
 

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Why would you want to use both a CB and GMRS? I thought that the CB radio is pretty short range and has a lot of interference. Sorry if pretty offtopic. I was thinking only going with GMRS, when I get to that point.
It really depends on the group you’re with. I understand there are a few that hang on to CB. I have one, but haven’t even heard truckers in a couple of years. Gmrs with the die hard no way I’m getting a ham group, and ham otherwise.