Looking for Wisdom on F250 GMRS Install

[Rfeustel]

Hello, I am new to the forum and new to GMRS. There’s a lot of great information in this forum but after doing a lot of searches I found a lot of info above my head about frequencies, programming, etc.. Can I ask for some laymen advice on my proposed install?

I have a 2011 F250 and I’m considering a mic controlled unit like the Midland XT575. I’d like to install the unit in the center console of the truck (I’ll flush mount an rj545 jack on the trim for a clean install). I’ll run power to a 15A upfitter switch, and run the antenna cable under the steering to the driver side door, under the trim, out the back, to the rear of the truck to put the antenna up on a rack. Here’s some issues I wonder about:

Heat dissipation for the base unit. Does it need more circulation that the bottom of the center console can provide?

Interference - the antenna cable path will run under the dash and in the wire channel along the rocker panels. Am I asking for interference trouble?

Length of cable - is placing the cable up high at the back of the truck too long for the GMRS (Losses? Noise?) Detail: It’s the short bed.


Thanks so much for any thoughts.

 

[K6GBW]

Putting the radio anywhere that it can't get good circulation has the potential to be problematic. It might be easier to just put the radio under the seat? Also, a good practice is to run the radio at low power unless you actually need the extra horse power. 50 watts radios do get hot if you key them down for an extended period of time. In everyday simplex operation like you'd find in car to car type situations you'd be surprised how little difference extra power makes. A fifteen watt radio compared to a fifty watt radio isn't night and day. It's a marginal increase in range with the extra power. I usually run my radio at five watts for repeaters and car to car within a mile. I crank up up to fifteen for car to car over that. As for routing the coax it shouldn't cause any problems. I've done what you describe dozens of times, however putting the antenna on a backrack may not work the best. You're best off with it on the roof. If drilling isn't something you feel you want to do then a hood mounts also works pretty well. The large "high gain" antennas also don't work very well if they don't have a large ground plane under them. I run a simple 1/4 wave that practically disappears and it works just fine.

What are you intending to do with the radio? Car to car, car to base, repeaters?

 

[Rfeustel]

Putting the radio anywhere that it can't get good circulation has the potential to be problematic. It might be easier to just put the radio under the seat? Also, a good practice is to run the radio at low power unless you actually need the extra horse power. 50 watts radios do get hot if you key them down for an extended period of time. In everyday simplex operation like you'd find in car to car type situations you'd be surprised how little difference extra power makes. A fifteen watt radio compared to a fifty watt radio isn't night and day. It's a marginal increase in range with the extra power. I usually run my radio at five watts for repeaters and car to car within a mile. I crank up up to fifteen for car to car over that. As for routing the coax it shouldn't cause any problems. I've done what you describe dozens of times, however putting the antenna on a backrack may not work the best. You're best off with it on the roof. If drilling isn't something you feel you want to do then a hood mounts also works pretty well. The large "high gain" antennas also don't work very well if they don't have a large ground plane under them. I run a simple 1/4 wave that practically disappears and it works just fine.

What are you intending to do with the radio? Car to car, car to base, repeaters?

Thank you for your answer to my noob question, K6. I am planning to do car to car and car to walkie (of course limited by the walkies) with my son. My wife is getting a Bronco and I have the F250. The F250 will be the bronco support/base camp vehicle and hauler. Especially if we were to get separated on the road or in the woods.

 

[mmckenna]

I have a 2011 F250 and I’m considering a mic controlled unit like the Midland XT575. I’d like to install the unit in the center console of the truck (I’ll flush mount an rj545 jack on the trim for a clean install). I’ll run power to a 15A upfitter switch, and run the antenna cable under the steering to the driver side door, under the trim, out the back, to the rear of the truck to put the antenna up on a rack. Here’s some issues I wonder about:

Heat dissipation for the base unit. Does it need more circulation that the bottom of the center console can provide?

Interference - the antenna cable path will run under the dash and in the wire channel along the rocker panels. Am I asking for interference trouble?

Length of cable - is placing the cable up high at the back of the truck too long for the GMRS (Losses? Noise?) Detail: It’s the short bed.

I've done installs on these series of Ford trucks. Full size American pickups are some of the easiest vehicles to install in.

Some suggestions:
Powering off the upfitter switches can create issues. Radios need nice clean power. The wiring for the upfitter switches is pretty good, but installers will always go direct to the battery. That's the best location for clean power, and will prevent a lot of possible annoying issues down the road. If you want to use the upfitter switches, use it to control a relay that controls the radio power coming direct from the battery.
Yes, it's extra work, but it's really worth the time and effort to do it right.

Routing your coax takes some planning. You do want to keep coaxial cable runs as short as possible. Routing needs to be carefully done to keep it away from sharp edges, heat and vehicle electronics. Running under the door trim will work fine, there's a clean path to the rear of the truck. You'll probably have some trouble getting a connector through there, so plan accordingly. If you can install your own coax connectors, it makes life much easier. If not, look for an antenna mount with an FME type connector, then purchase the FME to UHF male adapter to connect to the radio. I'm usually against adapters, but FME is designed for this sort of application, and it removes the challenges of terminating your own cable if you don't have the skill and experience to do it right.

Mounting on a headache rack or roll bar comes with challenges. Most antenna designs require a ground plane under the antenna for it to tune up and work correctly. Installing an antenna that requires a ground plane on a headache rack or roll bar will result in less than ideal performance. There are two options:
1. Get a "ground independent" antenna. These are usually 1/2 wave design and will work without a ground plane, however, they work better with one. You also need to address proper sealing of the coax cable and that will depend on your mount type.
2. Install the antenna on the roof of the truck. This will require drilling a 3/4" diameter hole, but it'll provide better performance. It also makes cable routing easier (it all stays inside the truck where it's warm and dry).
I'd strongly encourage the permanent mount on the roof. It does work better, and it looks much more professional. The antenna needs to be mounted away from other obstructions and at least 6" in from any edge of the roof. This will give it a properly sized ground plane. If you are not comfortable popping a 3/4" hole in your roof, there are radio shops that will do it for you. It may be worth the extra cost to go that route.

Heat dissipation:
Shouldn't be an issue. The radio can get warm if you are talking for a really long time, but 'normal' use shouldn't be an issue at all.

Cable routing:
Good coaxial cable shouldn't cause any issues. It's good to keep it away from large wiring harnesses and some equipment, but that should not be an issue in that truck with the route you are planning.

Length of cable:
Shorter is better. All wire has some amount of loss. As the cable gets longer, the losses go up. As the frequency goes up, so do the losses. On GMRS and a full sized truck, I don't think you are going to have any issues. What you don't want to do is have a bunch of coaxial cable rolled up in storage under the dash. The correct length of cable to use is just what you need to get from the antenna to the radio. No more, no less. (Leave a bit of slack on the radio end, obviously)

A couple of more pointers:
-Avoid the cheap antennas/mounts that they offer with these radios. You can do better, easily.
-Pay close attention to mounting. A 3/4 ton truck bouncing around, especially off road, can result in things like radios coming loose. I never use sheet metal screws in my installs. I always back up the radio bracket with an aluminum bar stock with holes drilled to match, and appropriate hardware with nylocks to secure everything.
-Ground the radio chassis to the vehicle body metal with as short a wire as you can. Do not rely on the long negative lead back to the battery. Actually, if you ground the negative lead for the radio to the vehicle body, you'll make life easier and avoid some common issues. And whatever you do, don't use cigarette lighter plugs.
-If your truck is loud, or you drive with your windows down/radio on, etc. add an external speaker. The small speaker in the handset will result in low audio with poor sound quality. Get a good external speaker, preferably a large one, and mount it somewhere that it's pointing towards the driver. It really makes a difference.

Don't forget the FCC issued GMRS license. $35 for 10 years.

 

[prcguy]

If the hood of the truck is flat near the cowl you could use a trunk lip NMO mount on the side edge of the hood or along the back edge. That would make for an easy short run of coax.

 

[K6GBW]

For what you are planning to do with the radios I think you'll be happy with the Midland. I know both mmckenna and prcguy. They are both very experienced radiomen and they give good advise. I know it can seem like a really big project starting out, but what you are planning really isn't that hard. I'm sure you'll be fine. Let us know how it turns out. We're always interested to hear feedback.

 

[Rfeustel]

I've done installs on these series of Ford trucks. Full size American pickups are some of the easiest vehicles to install in.

Some suggestions:
Powering off the upfitter switches can create issues. Radios need nice clean power. The wiring for the upfitter switches is pretty good, but installers will always go direct to the battery. That's the best location for clean power, and will prevent a lot of possible annoying issues down the road. If you want to use the upfitter switches, use it to control a relay that controls the radio power coming direct from the battery.
Yes, it's extra work, but it's really worth the time and effort to do it right.

Routing your coax takes some planning. You do want to keep coaxial cable runs as short as possible. Routing needs to be carefully done to keep it away from sharp edges, heat and vehicle electronics. Running under the door trim will work fine, there's a clean path to the rear of the truck. You'll probably have some trouble getting a connector through there, so plan accordingly. If you can install your own coax connectors, it makes life much easier. If not, look for an antenna mount with an FME type connector, then purchase the FME to UHF male adapter to connect to the radio. I'm usually against adapters, but FME is designed for this sort of application, and it removes the challenges of terminating your own cable if you don't have the skill and experience to do it right.

Mounting on a headache rack or roll bar comes with challenges. Most antenna designs require a ground plane under the antenna for it to tune up and work correctly. Installing an antenna that requires a ground plane on a headache rack or roll bar will result in less than ideal performance. There are two options:
1. Get a "ground independent" antenna. These are usually 1/2 wave design and will work without a ground plane, however, they work better with one. You also need to address proper sealing of the coax cable and that will depend on your mount type.
2. Install the antenna on the roof of the truck. This will require drilling a 3/4" diameter hole, but it'll provide better performance. It also makes cable routing easier (it all stays inside the truck where it's warm and dry).
I'd strongly encourage the permanent mount on the roof. It does work better, and it looks much more professional. The antenna needs to be mounted away from other obstructions and at least 6" in from any edge of the roof. This will give it a properly sized ground plane. If you are not comfortable popping a 3/4" hole in your roof, there are radio shops that will do it for you. It may be worth the extra cost to go that route.

Heat dissipation:
Shouldn't be an issue. The radio can get warm if you are talking for a really long time, but 'normal' use shouldn't be an issue at all.

Cable routing:
Good coaxial cable shouldn't cause any issues. It's good to keep it away from large wiring harnesses and some equipment, but that should not be an issue in that truck with the route you are planning.

Length of cable:
Shorter is better. All wire has some amount of loss. As the cable gets longer, the losses go up. As the frequency goes up, so do the losses. On GMRS and a full sized truck, I don't think you are going to have any issues. What you don't want to do is have a bunch of coaxial cable rolled up in storage under the dash. The correct length of cable to use is just what you need to get from the antenna to the radio. No more, no less. (Leave a bit of slack on the radio end, obviously)

A couple of more pointers:
-Avoid the cheap antennas/mounts that they offer with these radios. You can do better, easily.
-Pay close attention to mounting. A 3/4 ton truck bouncing around, especially off road, can result in things like radios coming loose. I never use sheet metal screws in my installs. I always back up the radio bracket with an aluminum bar stock with holes drilled to match, and appropriate hardware with nylocks to secure everything.
-Ground the radio chassis to the vehicle body metal with as short a wire as you can. Do not rely on the long negative lead back to the battery. Actually, if you ground the negative lead for the radio to the vehicle body, you'll make life easier and avoid some common issues. And whatever you do, don't use cigarette lighter plugs.
-If your truck is loud, or you drive with your windows down/radio on, etc. add an external speaker. The small speaker in the handset will result in low audio with poor sound quality. Get a good external speaker, preferably a large one, and mount it somewhere that it's pointing towards the driver. It really makes a difference.

Don't forget the FCC issued GMRS license. $35 for 10 years.

Wow, thank you for all of this information - I’m going to take a screen shot and save it. I Am a lot less intimidated now. I will definitely custom cut the coax (Used to do it pre twisted pair in LANS, gotta research weather sealing).

I’ll definitely run direct to the battery and a more local ground. THANK YOU!

Is there a favorite coax these days for The GMRS?

 

[Rfeustel]

I made some thank yous and comments above (And further questions). Really, thank you all so much. This is a first for me.

Is there any issue using shielded cat 5 to put the unit further back with better circulation and a shorter antenna wire, but with a longer mic extension? For example, a behind the back seat install (although now the power line is longer).

 

[mmckenna]

Wow, thank you for all of this information - I’m going to take a screen shot and save it. I Am a lot less intimidated now. I will definitely custom cut the coax (Used to do it pre twisted pair in LANS, gotta research weather sealing).

It depends on which NMO mount you use and how you install it. If you are going to use the headache rack/roll bar, fender bracket, you need to make sure you are using one of the enclosed NMO mounts. The standard NMO mounts are open on the bottom and the coax is exposed. That's fine on an installation where the NMO is mounted through the roof. The coax will be dry. If you mount on a rack/bracket and the underside is exposed, you should use one of the Larsen NMOHF style mounts (or similar), they are enclosed. Slide a piece of marine grade/adhesive lined heat shrink over the coax and slide it up over the part where the coax enters the mount. Shrink it and the adhesive will flow and seal everything up really nice.

I’ll definitely run direct to the battery and a more local ground. THANK YOU!

Biggest issue I see on this site is people trying to cut corners on the wiring. They tap into existing wiring or fuse blocks, or worse, cigarette lighter sockets, then complain about interference, noise and other issues. It really does make a difference. If you want the radio to be reliable, putting the extra effort in really makes a huge difference.

Is there a favorite coax these days for The GMRS?

NMO mount with RG-58 is just fine. I run an 800MHz system at work. The coaxial cable losses are increased as you go up in frequency. I've never had an issue running RG-58 in a mobile install.
You can run a larger cable, but you need to consider the installation. Running a stiff cable like LMR-240 can be difficult. When it comes down to it, the length of the cable is pretty short and the difference really isn't that big.