Honda Fit 2012 mobile install question

[mmckenna]

In post 6 is where the antenna for am/fm is. I was thinking putting the mobile antenna up front or by front hood area. Scanner antenna towards the back I'm not sure if am/fm will effect the scanner antenna.

The AM/FM antenna, if it's too close to the scanner antenna, will act like a reflector. You'd be wise to give it 2 feet or so of space between them.

The higher up you can place the antennas, the better they will work. Less shadowing from the vehicle windshield/roof. Ideal place is on the roof, but if that's totally out of the question, at least spread them out as much as you can.
For the GMRS antenna, you ideally want at least a 1/4 wavelength worth of ground plane in all directions horizontally in all directions under the antenna. Anything else will impact performance and may make it somewhat directional.

 

[bravo14]

The AM/FM antenna, if it's too close to the scanner antenna, will act like a reflector. You'd be wise to give it 2 feet or so of space between them.

The higher up you can place the antennas, the better they will work. Less shadowing from the vehicle windshield/roof. Ideal place is on the roof, but if that's totally out of the question, at least spread them out as much as you can.
For the GMRS antenna, you ideally want at least a 1/4 wavelength worth of ground plane in all directions horizontally in all directions under the antenna. Anything else will impact performance and may make it somewhat directional.

The roof is 71 inches from front to back. The am/fm antenna is 7 inches from the gap for the hatch back.

 

[bravo14]

Here is the scanner antenna. It is the

SpectrumForce Wideband Antenna with Mag Mount and SMA | Scanner Master

Small, light-weight, unobtrusive 17' scanner antenna are perfect for those who want good quality wide-band reception.

www.scannermaster.com

 

[mmckenna]

The roof is 71 inches from front to back. The am/fm antenna is 7 inches from the gap for the hatch back.

Sorry, didn't look at the photo and was thinking the AM/FM radio antenna was up on the front fender like the 'olden' days'.

So, that's easy. My wife's new truck has the AM/FM/Sirius/XM/GPS antenna on the back of the cab. I installed a 50 watt VHF mobile in it. The VHF 1/4 wave whip is about 16" forward of the stock antenna, and no issues at all.
Would be fine for the scanner antenna. That'll still leave you room for the GMRS antenna. It'll need some spacing from the other two antennas, but 2 feet should be plenty. You can even set them off to either side if that works better for coaxial cable routing.

 

[bravo14]

I was thinking putting the gmrs antenna on driver side and scanner antenna on passenger side. I'll look see what spacing is good.

 

[03msc]

You will be much happier drilling an NMO and using a 1/4 wave VHF antenna or low profile antenna or something (depending on what frequencies you are focusing on receiving) for the scanner than you will with that mag mount...just sayin'!

 

[bravo14]

I went out today and did some measuring on the car roof.
From the tip of the car am/fm antenna to the front of windshield is about 64 inches.
From Driver side to the Passenger side is 38 inches. 19 inches in the middle of the two.
I could put the mobile antenna on drive side on top of me and the scanner antenna on passenger side on the back side.