Ham Radios & Scanners in the car

[natedawg1604]

So, I just got my ham license and will begin using a CS-750. My car already has 3 NMO antennas for scanners (all permanently mounted on the roof), presumably they will now be used for Ham radio as well. In general, what are "best practices" for using scanners along with ham radios in the car, so as to avoid damaging the scanners from desense and so forth?

 

[mmckenna]

Separation is key. Keep the scanner antenna as far away from the transceiver antenna as you can.

When deciding antenna location, keep in mind that coaxial cable has loss that depends on frequency and length. The higher the frequency, the more the loss. The longer the cable, the more the loss. For this reason you may want to put the higher frequency radios on the shorter cable runs.

 

[ladn]

Separation is key. Keep the scanner antenna as far away from the transceiver antenna as you can.

That said, how your particular scanners behave in a high RF environment is also a factor.

I used to have three scanners and a 90W VHF radio in my work vehicle. All the antennas were trunk mounted and I never experienced damage to the scanners from RF overload. The scanners suffered from desense when I keyed up, of course, and picked up a few "birdies" from each others' local oscillators, but no long term damage. Your mileage will vary.

 

[jwt873]

I have a Larsen 2/70 NMO dual band in the middle of my car's roof and a 1/4 wave 2 meter antenna installed on a trunk lip mount at the back of the car. Distance between the antennas is about 4.5 feet.

I run my TH-D72 into one antenna, so I can beacon APRS. It goes through an amplifier that boosts the 5 watts to 30 Watts. The other antenna is connected to my IC-7000 which puts out 50 Watts. There is some desensing, but like ladn, I've never experienced any damage.