Hi everyone,
I thought I'd post a few pictures of an install I did on a 2005 Chevy Equinox that took advantage of some stock features of the vehicle.
For the mounting location, I was looking all over for a place to put the radio that would be out of the way and noticed a small compartment below and to the left of the steering wheel in the dash. I'm not sure what it's intended for, but I hadn't ever really even noticed that compartment before. As luck would have it, it's the perfect size to mount an M1225 mobile radio in. The radio slides right in with a firm push and the fit is tight enough that no mounting bracket is even used...the radio is held in by friction. This doesn't allow for great air cooling of the heat sink, but I use it for receive-only 99% of the time, and have all channels programmed for low power (5W) if I do need to talk. I drilled two holes in the back of the compartment for power and antenna wires. Power wires are then run through the firewall grommet right behind the radio to the battery, piece of cake.
For the antenna, I modified the Onstar cellular antenna for VHF use. The Onstar antenna on this vehicle is the older style that has a "rubber duck" style cellular antenna. This modification would not be doable on the newer "shark fin" cellular antennas.
To modify the cellular antenna for VHF use, I simply unscrewed the rubber duck antenna. It turns out that the thread used for the rubber duck is the same thread used for the FM whip antenna on GM vehicles (M5 or M6 I can't remember which). I had planned on getting a regular "straight" FM whip and cutting it down to size for VHF use, but I happened to find a "cellular look alike" FM antenna at O'reilly Auto Parts that was shorter than a regular FM antenna. I wasn't sure what frequency it would be resonant at, but for $8 it was worth a shot. Turns out the SWR is beautiful all the way across the VHF band (it's terrible at UHF though, so don't use this particular whip for dual-band operation). Here's a picture of the stock Onstar antenna next to the modified version (sorry for the poor lighting it was getting dark when I took the pictures):
The Onstar unit is behind the dash just to the right of the steering column. The RG-58 cable going to the unit connects to the cellular antenna (the smaller coax cable goes to the GPS antenna). The next two pictures show the Onstar unit with the antenna cable connected and disconnected.
As it happens, the cellular antenna connection on the Onstar unit is a mini-uhf connector, which is the same as the connection on the M1225. Could I be so lucky? Unfortunately, no, for two reasons. First, while the connector on the Onstar unit is threaded, the connector on the RG-58 is a push-on connector. The M1225 doesn't have the mating locking feature for the push-on connector. so it would fall off too easily. Second, the RG-58 cable from the Onstar antenna to the Onstar radio is run down the passenger side of the car, and there isn't any extra cable to allow me to get the connector over to where the M1225 radio is mounted on the driver's side. I probably could have torn the car apart and rerouted the coax down the driver's side pillar, but I decided to just extend the cable to get it where I needed it instead.
So in the end I got the radio mounted without a bracket, it's in a convenient but out of the way location, and I didn't have to add an antenna to the vehicle. Sometimes the stars align!
Regards,
Andy
I thought I'd post a few pictures of an install I did on a 2005 Chevy Equinox that took advantage of some stock features of the vehicle.
For the mounting location, I was looking all over for a place to put the radio that would be out of the way and noticed a small compartment below and to the left of the steering wheel in the dash. I'm not sure what it's intended for, but I hadn't ever really even noticed that compartment before. As luck would have it, it's the perfect size to mount an M1225 mobile radio in. The radio slides right in with a firm push and the fit is tight enough that no mounting bracket is even used...the radio is held in by friction. This doesn't allow for great air cooling of the heat sink, but I use it for receive-only 99% of the time, and have all channels programmed for low power (5W) if I do need to talk. I drilled two holes in the back of the compartment for power and antenna wires. Power wires are then run through the firewall grommet right behind the radio to the battery, piece of cake.
For the antenna, I modified the Onstar cellular antenna for VHF use. The Onstar antenna on this vehicle is the older style that has a "rubber duck" style cellular antenna. This modification would not be doable on the newer "shark fin" cellular antennas.
To modify the cellular antenna for VHF use, I simply unscrewed the rubber duck antenna. It turns out that the thread used for the rubber duck is the same thread used for the FM whip antenna on GM vehicles (M5 or M6 I can't remember which). I had planned on getting a regular "straight" FM whip and cutting it down to size for VHF use, but I happened to find a "cellular look alike" FM antenna at O'reilly Auto Parts that was shorter than a regular FM antenna. I wasn't sure what frequency it would be resonant at, but for $8 it was worth a shot. Turns out the SWR is beautiful all the way across the VHF band (it's terrible at UHF though, so don't use this particular whip for dual-band operation). Here's a picture of the stock Onstar antenna next to the modified version (sorry for the poor lighting it was getting dark when I took the pictures):
The Onstar unit is behind the dash just to the right of the steering column. The RG-58 cable going to the unit connects to the cellular antenna (the smaller coax cable goes to the GPS antenna). The next two pictures show the Onstar unit with the antenna cable connected and disconnected.
As it happens, the cellular antenna connection on the Onstar unit is a mini-uhf connector, which is the same as the connection on the M1225. Could I be so lucky? Unfortunately, no, for two reasons. First, while the connector on the Onstar unit is threaded, the connector on the RG-58 is a push-on connector. The M1225 doesn't have the mating locking feature for the push-on connector. so it would fall off too easily. Second, the RG-58 cable from the Onstar antenna to the Onstar radio is run down the passenger side of the car, and there isn't any extra cable to allow me to get the connector over to where the M1225 radio is mounted on the driver's side. I probably could have torn the car apart and rerouted the coax down the driver's side pillar, but I decided to just extend the cable to get it where I needed it instead.
So in the end I got the radio mounted without a bracket, it's in a convenient but out of the way location, and I didn't have to add an antenna to the vehicle. Sometimes the stars align!
Regards,
Andy
