Good advice above.
I'm running a similar setup/different radio.
I've got a 2010 Polaris Ranger and I ride in similar conditions. Either far Northern California, or far Eastern California/Western Nevada. Lots of trees, mountains, canyons, hills, water crossings, snow, mud, etc. etc....
I've tried a number of different antennas on the Polaris Ranger and my dad and brothers Polaris Rzrs.
1/4 wave VHF antennas (about 19" tall) will work, but they rely on a ground plane under the antenna. This needs to be a metal surface, preferably 19 inches in all directions. This is entirely do-able on a UTV, but you'll need to have a roof. Mounting the antenna through the center of the roof will give you a proper ground plane under the antenna. The proper ground plane will keep coverage equal in all directions. When you offset the antenna on the ground plane, a situation where you may not have 19 inches in all directions, your antenna pattern will become lopsided and you may experience coverage deficiencies in certain directions.
Most mobile antennas require a ground plane, so going from that angle, you need to have a roof for it to work. Mounting one of these antenna on the roll cage will result in an unequal ground plane.
There is an option, though...
A half wave antenna does not require a ground plane (although it works better with one). A half wave antenna can be mounted just about anywhere and work.
After trying 1/4 wave and 5/8th's wave antennas on my Polaris, I finally tried a half wave. It works very well and seems to outperform the others.
Being that it doesn't require a ground plane, I can mount it off set to one side on the top of the roll cage.
This has worked well and it's taken quite a beating. Rough trails, tree branches, being on a flat bed trailer at highway speeds, etc. and no issues.
A couple of things to consider.
- Ideally, you do want to put the antenna in the center of the roll cage. Do this if you can. I didn't for various reasons, but it still works as is.
- RF radiation exposure at the power levels your radio runs at isn't trivial. While it's not going to give you cancer (right away) it's not considered safe by any reputable agency. Ideally you do want a couple of feet between your head and the antenna. Since your head is not easily relocatable, you may want to think about where you mount the antenna.
-You absolutely do want the antenna up as high as you can get it. Top of the roll cage is the way to go. Placing it anywhere else is going to result in decreased performance.
-You do want the spring base. While the whips will take a fair amount of abuse, mine has a slight kink in the very end. The spring probably has prevented me having to replace the whip. Hitting a tree branch at fast trail speeds is going to happen, so plan for it.
-I ran a roof on my Polaris for a while. I disliked it and removed it after a few years. The aluminum or steel roof tops are good for mounting antennas, but it's up to you. Ideal place would be to mount the antenna on the roof.
-You need to have a solid mount. Vibration and tree branch strikes will let you know quickly if your mount is not up to the task. There are some ready made mounts that will fit the roll cage pipe diameters. They work well.
-Make sure you -carefully- route the coax cable. Anywhere it's exposed to trail debris, rocks, mud, etc. is going to be an issue. Secure it along the back of the roll cage if possible. Routing it to the radio is going to take some thought. Remember that those rocks flying off the tires are going fast and -will- damage the coaxial cable. For this reason, inspect it often.
Some might try to steer you towards the higher gain antennas. 5/8th's waves and larger do provide some additional gain, which can make it act like your radio is running more power than it really is, but this comes at a cost. Gain antennas work by focusing the radiated power out towards the horizon. This is great if you are riding flat trails out on the plains, but you aren't. And I"m not. Lower gain works better. When on off camber trails, climbing/descending hills, etc. the tight pattern of the higher gain antennas can send more of your RF power towards the sky and ground. Don't fall into the trap of wanting more radiated power by using high gain antennas. In this instance it will work against you.
A few other items to consider:
Route the power for the radio directly off the battery. The ignition systems on some of the engines can be a bit noisy. Tapping into existing wiring can introduce a lot of noise into your radio. You do not want this.
An external speaker is really a good idea. The smallish speakers on these radios are fine inside a quite car, but they are useless when running down the trail at 40+mph. If you wear a helmet, you'll have a hell of a time hearing radio traffic. I'm running a large external Motorola speaker on my VHF radio in the Polaris. Running flat out on a trail (50+mph) with a full face helmet on I can still clearly hear the radio.
Careful where you mount the radio and speaker. It -will- get wet, muddy, snowed on, rained on, etc. Mine is under the dash board. Actually, I'm running a Motorola CDM-750 VHF. The actual radio guts are inside the glove compartment. The only thing exposed to the outside is the radio control head, well under the dash, and the speaker, also under the dash. So far, no issues.
Vibration is a real issue. Make sure your radio is well secured. Mine is bolted through the plastic under the dash and through an aluminum bar I installed to spread out the weight. Don't rely on things like double sided tape or sheet metal screws. They won't last.
Secure all the wiring well. Make sure vibration won't knock anything loose. My power connection at the battery is done with crimped ring terminals. The terminals are fully crimped, a touch of solder added, and then followed up with marine grade heat shrink. About 2K miles on the Polaris and no issues.
For the antenna mount:
I fabricated my own using this bracket as a starting point. Make sure the mount you purchase fits the diameter of your roll bar. Different brands use different diameter roll bars!
https://www.rockymountainatvmc.com/...ontal-Flag-Mount?term=roll+cage+antenna+mount
For the antenna base:
You'll want an NMO type base. You can find these online from several sources. Use a brand name mount, NOT Tram or Browning. These two brands (actually the same company) are mass produced in China and have questionable quality. Go with Larsen, Comtelco, Laird, antenex.... The NMO mount is a standard size, so the NMO mount from one brand will fit the antennas from another -in most cases-.
For the coaxial cable:
This will usually come as part of the NMO antenna base. Make sure you get the correct connector on the end. Your radio requires a Male "UHF" type mount, also called a PL-259. If you have not installed coaxial connectors before like these, buy the mount with the connector already installed. Try to NOT use adapters if at all possible. These create a failure point.
For the antenna:
Something like this will work just fine:
PCTEL | VHF Base Loaded Chrome Coil Antennas, No Ground Plane | MHB5802(S)
A lot of these parts you can get from ruggedradios.com They tend to be quite expensive though. Shopping around will get you a better price (easily). If you have any specific questions, post back here and we can assist.