mobile scanner antenna set up questions


Junior Member
Hello all, I have couple of questions related to mobile scanner antenna setups. I am looking to install a uniden bcd996p2 in my 2017 ford explorer xlt. I currently have a vhf mobile in the car and am looking to use the scanner to monitor our local FDs on uhf and then monitor most of my local area on p25 when the new p25 system goes live in another year or 2. I don't particularly want multiple antennas on the car both so I don't look wackerish and I'm trying not to make the vehicle recognizable due to work. So I have two questions. First, can I run the scanner off the same antenna as the vhf mobile? I know if you were to run two radios off one antenna, you would need some sort of filter, such as a duplexer/diplexer/whatever the techincal term is to prevent rf energy causing damage from one radio to the other. Would I still need some sort of filter if I were to have a radio and a scanner on the same antenna? My other thought is to try and use a splitter to connect the scanner to the antenna for the car's am/fm radio. I knew someone who did this in the past but I have no idea how good a signal he recieved and unofrtunatley I can't ask him about it anymore. Does anyone have any thoughts?


Gold Supporter
I did the splitter/filter with my cb radio in my last truck. It worked but I still ended up going with a separate antenna anyway. If your scanner is uhf you could get away with a short antenna (3-6 inch) that's not so noticeable.

The main thing is to get some sort of antenna outside the cabin of the car. If you're system is going P25 or Starcom (that's what we're on) then an interior antenna up under the headliner should work as well for listen only.

Jarred J.

Archive Expert
Silver Supporter
1st question.. yes but no...

you could use the same antenna as long as you dont transmit on the radio... some scanners will take up to 50 watts directly into it before you fry it.. (accidentaly did it with a scanner one time.. the display went dim for a few days then eventually came back up)
you are asking about a duplexer.. these only work if

A. you have 2 RADIOS on different bands that you want to use a dual band antenna

B. you have 1 dual band radio that you want to separate into 2 antennas..

2. there are splitters on amazon for like 20 bucks.. a scanner doesnt need a "frequency specific antenna" as SWR is only affected by "power going out"

the reason why i say radios on A. is because the wave lengths on the bands do not affect each other if the radio is looking for that wavelength.. for easier understanding a cb can put as much power as you want (law says 4 watts) but a FRS/ GMRS radio will not pick it up due to its wavelength variances.. ( 1 wavelength of a CB is 11 meters long, where as for FRS GMRS its either uhf 20 inches or vhf 35mm where as a scanner IS looking for that other frequency...


Junior Member
so it sounds like using the antenna for both my mobile and a scanner is out, since I do use the mobile to transmit. Guess I will look into putting a splitter on my am/fm antenna cable and running the scanner off that antenna


Established Member
Only options is splitter or its own antenna. Definitely do not want to split into your mobile

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