Two Radios, Two Antennas?

[back4more70]

Hypothetical question: If I run two separate radios in my car (2m and 70cm) with two separate antennas on the roof, would this setup be a problem i.e. overloading or desensing?  The antennas would have to be less than four feet apart due to the roof size.

[kidphc]

Shouldn't be a problem. (Big shouldnt).

Remeber, 70cm is third harmonic ( I think) of 2m.

So best practices would be shut one down when in use.

My xtl 5k will overload my ftm400 when transmitting on occasion. But that is when the frm400 is listening to 70cm, the xtl5k is used for gmrs. It's to be expected at 4.5 feet between the antennas, especially since 70cm and gmrs are so close in frequency. I haven't seen issue on the 2m side when transmitting on gmrs.

I say if, since Marc had problems with his 2m xtl 5k, that one he thinks it might have been the gmrs xtl5k, that damaged it. Hopefully, he can chime in with his real world findings.

But if you are really worried. Run some cheap filters.


Sent from my SM-S901U using Tapatalk

[gortex2]

I have 6 NMO mounts on the roof of my F150 (crew cab). All are hooked up to APX mobile radios. I see no noticeable issues. Really will depend on power and quality of radio. Cheap radios and high power don't go well together. 

[nokones]

Ditto! My XTL5000 base radio and my Repeater Station also are not bothered by my other same proximity radios transmitting when receiving. That is not the case with the other same proximity radios receiving and the XTL5000 radios and/or repeater station transmitting.

[marcspaz]

I have an FTM-300DR, which has the ability to run 2m and 70cm at the exact same time using the same antenna and there is no desense issues.

 

It's mostly going to depend on the frequencies in use and the filters on the radios.