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Stupid question on mobile antenna seperation...
Posted: Thu Apr 24, 2008 9:09 am
by radio64
OK, here's my situation: a FD just got a used rescue truck and I am installing the comm equipment in it. Previous owners had low, vhf, and uhf radios in it, with all 3 antennas on the cab roof. new owner has lowband in cab, vhf and a seperate low in the box. Problem I'm trying to prevent is overloading the front end of either LB radio when the other is being used. Simple solution is turning off the other radio when not in use, but I know they'll forget...
The 2 antennas are around 18" or so apart. Any thoughts or suggestions? Think the radius mobiles (appx 60w) will suffer major damage? Thanks.
Re: Stupid question on mobile antenna seperation...
Posted: Thu Apr 24, 2008 9:47 am
by kf4sqb
As far as the radios being damaged, doubtful. Biggest problem I see there is horrible feedback if they are on the same (or even close to the same) frequency, and the volume is turned up really loud on the one not in use. My first suggestion would be to ditch the idea of two radios and use a single unit with dual heads. Look into the "QuickMount" dual-head kits for the Radius series. Work great, simple to install, and are cheaper than two radios. The only other solution I can see if they insist on separate radios is to electrically "interlock" the two radios, so that only one can be powered up at a time.
Re: Stupid question on mobile antenna seperation...
Posted: Thu Apr 24, 2008 10:33 am
by radio64
I would have loved to use a dual head setup on it, would give me an additional antenna for future... Biggest problem is running the cable from the cab into the box. The conduit that is there (through the floor of the cab, around the frame somehow, then up into the box, twisting around behind cabinets) is pretty full already, won't fit the db25 end through (I doubt I could even get the cable itself through there) Previous owner had one radio in the cab (center antenna on the roof) and the other 2 radios in the box (outter mounts) (didn't have the same issue because they used low, vhf & uhf) and left the mounts and power wires there (but snipped off the polarized M connectors, or used some different radio) so if I get the power connectors in place, the install is essentially done. This truck is an older style (1989) conventional chassis with a walk in box body (no pass through) I don't think feedback will be an issue since the radios are seperated quite a bit (and no direct speaker issue) I'm thinking the radio in the box (command area) wouldn't be too loud anyway. No driver in the cab when command is working...
I'll mess around and see what the levels work at before feedback and see if that will work... (occasionally on the same frequency, but the sepearation is small anyway: 46.50, .42, .30, .24, etc... Thanks for BOTH replies! I'll look into that!