Multi Band Antenna

Hello,
I was looking at setting up my mobile rig. I am looking at the following 3 radios a dual band 2 meter/440, Cb radio, and a scanner. I was planning on putting the cb on its own little 8 in antenna I found at a local electronics store. However instead of adding 2 separate antennas i was wondering if anyone has ever tried transmitting on a multiband antenna. Something like this (SpectrumForce Wideband Antenna with Mag Mount and SMA) or this (Laird Multi Band Mobile Antenna). That way I can run both my scanner and or mobile off one antenna and save my car from growing more antennas.

Thank you all have a nice day.

You won't be able to run a scanner and a transceiver on the same antenna.
The transmit signal will get into the scanner and fry the soft/expensive bits inside.
You can use diplexers, but they'll send broad chunks of spectrum to only one of the radios, leaving the other one deaf as a post.
You can run some very expensive/large duplexers, but you'll still be blocking what the scanner can hear.

You really do need to have the amateur radio on it's own antenna and the scanner on a separate one.

Also, you're going to get extremely poor performance fro an 8 inch tall CB antenna.

I was planning on using a switch between the two different devices. So when I want my scanner I switch to scan and when I want to use my amature rig I switch to that. I was trying to save antennas and time but I see what you were saying I just didn't know if it could or had been done.

As for the cb antenna its only for in town communication (<2 miles) and it fits my bill of a sub 2 ft non mag mount antenna but I'll look for a diifrent one too. Thanks for the help thought.

Yeah, and antenna switch will work fine.

You just have to make sure you switch to the right radio before transmitting. Having the antenna switched to the scanner and then trying to transmit with the amateur radio runs the risk of damaging the amateur radio. Not having a proper resonate antenna attached will eventually cook the final transistor if you transmit.

Something I've been looking into is building a Rf sensing antenna relay pack for a CB and low band radio. When the low band rig keys, shunts the CB to a dummy load. When the CB keys, shunts the low band radio to a dummy load. When both radios are keyed they both listen off the same antenna.

There used to be a unit made by Shakespeare that did that for VHF marine radios. They were intended for larger boats with a VHF radio on the flying bridge and one in the cabin. Keying a radio switched it over to the correct one.
I haven't seen one in a few years.

I'm glad I read this post...LOL I have a brandy new TS-2000 sitting in my basement just itching to get on the air but I haven't set up my antennas yet. I have a triband Comet antenna I use for my scanner attached to about 12 feet of coax but too afraid to try that antenna.