Beginning thread on Radio Installations

Excellent question !

When discussing ground plane, flatter is better but not to the degree that it would be detrimental to the overall performance of the antenna itself. It is far better to have an oddly shaped ground plane than to have none at all. Without getting too far down the rabbit hole (it’s ridiculously deep), engineers use computer modeling to estimate the radiation patterns of the antenna under transmit conditions. They look very much like “lobes”. A perfect scenario would be 2 exact sized lobes or spheres around the antenna mast. A ground plane that’s oddly shaped may alter the sizing of those lobes but without a ground plane those lobes are almost non-existent and that is the down and dirty for why a ground plane is necessary. There is soooooo much information out there with computer modeling it would make your head spin. The short answer to your question is no, the odd shape of the XRC metal roof will not significantly alter the overall performance of the antenna. The difference would be negligible.

Now that we’ve discussed the selection, wiring, and installation of your new comms equipment, we will discuss tuning the antenna for best performance. The metric for this is SWR or commonly known as “reflected power”. In a nutshell, tuning the antenna is the method of “matching” the impedance between your cabling and the antenna so the signal grows through the system in the most efficient manner and gives the best watt output at the antenna. The better the impedance match, the better the system performs and the less power is lost to the installation. Many don’t understand the importance of this step in the overall install so here we go.

First, the gold standard for SWR is expressed as a ratio, and is 1:1. The more out of tune your system is the higher the number will go, let’s say 1.5:1 or 2.5:1. As these numbers rise, the more power from your radio gets absorbed into your antenna and coax and is “reflected” back into the radio. Why does it matter? Well, when these number get around 2:1, the amount of power reflected back into the radio can cause damage over time to the electronics inside the radio in the form of heat which will decrease the longevity of your expensive (or not) component and decrease your transmit range significantly. It will also cause your radio to not receive as well as it could as well. When your group is spread out over a decent distance for dust, etc, your range will become more important as the distance grows, especially if someone has an issue on the trail or, God forbid, has an accident. The ability to communicate with your group for trail directions, or get in touch with someone in the event of an emergency with no cell coverage is just a few of the reasons we have comms in our cars in the first place. Don’t handicap it with a poor performing radio when tuning is easy with some knowledge and inexpensive equipment.

Let’s talk in terms of practicality. If you have a SWR of 1:1, this basically means all of your available transmit power is available at the antenna. When that number rises to 3:1, you have lost a whopping 50% of your transmit power. So, if you have a 25 watt radio with a SWR of 3:1, you have only 12.5 watts of power available at the antenna. Couple that with a poor ground plane and you may as well have an 8 watt handheld with a rubber ducky antenna because your expensive radio won’t perform any better than that.

So, what do we need to tune an antenna? First, an inexpensive SWR meter (available from Amazon, EBay, etc. Some jumper cables to attach the meter to your radio and antenna which you can make yourself or purchase, and an appropriately sized Allen wrench to remove the mast. You will need something to cut the mast as well. Using the meter is easy once it’s hooked up properly (directions are normally included with the meter). You basically tune your radio to the frequency you want to test, press the transmit PTT switch and BAM, you have your first reading ! Based on that reading you will need to determine whether to lengthen or shorten the antenna. So, first loosen the Allen screws that hold the mast to the base and raise it about 1/2 inch and retighten. Run the test again. If your SWR comes down (closer to 1:1) then you know the mast needs to be longer. If the SWR goes up, then you need to trim the mast. Easy right?

Not so fast. First, let’s talk about the frequency to test. As I stated in the previous post to Hollywood, we tune the antenna for a range of frequencies for best results. Go back and read that post again if you don’t remember the details. Use some simple math and calculate the “middle” of the frequencies you have programmed in your radio. Take the highest plus the lowest and divide by 2. Tune your radio to that frequency (manually if you can, or choose a pre-programmed frequency that’s as close as you can get). I’ve found that on the VHF side the “RESCUE” frequency of 155.100 is pretty darn close. This will be your test frequency.

When cutting the mast, be sure to do this in very small increments, especially as the numbers get closer to that magic 1:1. You can always cut more you just can’t put metal back. Most will say to cut no more than 1/4 inch at a time. A good rule of thumb is when the SWR gets to 1.5:1, cut only 1/8 inch at a time. How will you know when it’s as good as it’s going to get? Well, after your cut, the SWR will either remain the same or go back up slightly. If it does go back up you can use the Allen screws to raise the mast a little to get that number back down. There isn’t a whole lot of adjustment available so be careful. A properly tuned antenna is considered to have an SWR of 1.5:1 plus or minus .2 so a maximum of 1.7:1. I like to try and sneak up on it so I might cut (or grind) 1/32 or 1/16th when my SWR gets that close. If you truly screw it up royally and cut too much, replacement masts are available for a reasonable price and you can start all over again.

Once you have your lowest SWR on your test frequency, tune your radio to the lowest frequency you have programmed and run the test. Do the same with your highest frequency. You will notice that your SWR will only go up slightly between the top and bottom. As an example, when tuning to RESCUE, my SWR is 1.2:1. At the bottom (like Weatherman), my SWR is 1.26:1 and at the highest its 1.27:1 see, almost a negligible change on your whole frequency range. For those that have dual band antennas, test the GMRS frequency at 465ish and note the results. A good quality antenna should produce SWR very close to what you got on VHF, perhaps slightly higher. My setup shows 1.35:1, more than acceptable.

The whole process doesn’t take very long and is well worth the effort. If you don’t want to invest in the equipment (less than $100), ask the forum for a charitable soul near you that’s willing to help out or find a local HAM radio operator and they are always glad to help out. I honestly don’t know a single HAM guy that doesn’t have a SWR meter in the frequency range we will be using. If you’re in or near Tucson, look me up and I will be glad to help.

We talked about the most technical part of the radio and intercom process so I’ll open this up to questions and comments. My question to the forum is “What would you like me to cover next?”
Programming / Repeaters (GMRS only) / Troubleshooting / ??????

I’ve often been asked the age-old question regarding communications “which is better, VHF or UHF?” Below I pasted a good short article I found that does a good job of explaining it without getting too technical:

VHF vs UHF Which is Better?
The two frequency ranges (also called "frequency bands") used in most two-way radios are VHF (Very High Frequency), and UHF (Ultra High Frequency). We are often asked "Is VHF or UHF better?" Neither is inherently better, they each have strong points and weaknesses.

VHF frequencies can penetrate objects better than UHF. VHF can also travel farther. If a VHF wave and a UHF wave were transmitted over an area without barriers, the VHF wave would travel almost twice as far. "Sign me up for VHF!" you say. Not so fast. Even though VHF can pass through obstacles better and travel farther, that doesn’t mean it's always the better choice. "Why?" you ask. It's because of the difference between how VHF vs UHF signals react around structures. Remember, UHF signals are shorter than VHF, this is important when you're in or around buildings.

To explain this let’s take an example. Assume you are trying to communicate from one side of a commercial building to the other. In between is a metal wall with a three-foot opening. Radio waves can not pass through metal. The UHF wavelength is roughly one and a half feet wide, the VHF wavelength is roughly five feet wide. The UHF signal (1 1/2 ft) passes through the door easily. However, the VHF signal is reflected since it is wider than the door. As you can see, UHF is better at navigating through the smaller spaces within a building to reach it's destination. VHF signals are often blocked by metal within the building.
So to sum it up, it's a trade-off. But the general rule-of-thumb is if you are using the radio primarily outdoors where you will have clear line-of-sight then VHF is a better choice because it's signal will travel farther. BUT, if you will be using your radio in or around buildings, in urban areas, or heavily wooded areas, then UHF is a better choicebecause it's signal will navigate around structures better, not being blocked as easily as VHF. The trade-off you are making is longer distance (VHF), vs avoiding possible "dead spots" in and around structures (UHF).

The key takeaway here is “heavily wooded areas”, especially in the national forests and on the east coast where the trees are tall and there are all kinds of obstacles. This is some of the driving force behind switching from our “race” frequencies in the VHF spectrum to FRS (Family Radio Service) and GMRS (General Mobile Radio Service). While both bands are “line-of-sight” generally the UHF will perform better in the terrain we often ride in. With that said, let’s talk a little bit about FRS and GMRS. The FCC has set aside these frequencies for the public use. They do require a license, which requires no testing, simply a registration and a nominal fee online. The whole process takes just a few minutes. The license covers you and your family. There are power limitations on these frequencies, especially the FRS channels but most seem to ignore that. No worries though as I’m not getting into that here. The GMRS channels are allowed up to 50 watts and those are the frequencies used for the thousands of repeaters across the country. Many if not most are open for use by any licensed operator and all you have to do is request access and give your FCC issued callsign. These can be found on the ‘MyGMRS” website. Having the availability of a repeater in the area you ride can greatly increase your ability to communicate with your group and contact someone in case of emergency with no cell service. These repeaters are often placed on the highest peaks and offer varying ranges, some up to 100 miles. By using repeaters in practical use, if your group is going through terrain that has hills or valleys that could separate you, your “line-of-sight” becomes impractical. Using a repeater, you have line of sight to that unit, which in turn has line of sight to your group. That’s not always 100% given the terrain but more often than not it works just fine. The popularity of this GMRS band haas grown exponentially over the years and it seems like repeaters are going up everywhere. Some are owned by clubs, some are private. The website will tell you who owns what and how to get access. Typically these repeaters will use “tone codes” to allow your radio to activated the repeater and be able to receive the outgoing transmission as well. The repeater uses 2 frequencies, commonly referred to as “frequency pairs”. One frequency in to the repeater and one frequency out of the repeater, separated by 5.0 MHz. It’s very easy to program into your radio and when using CHIRP NEXT, the program will do it for you as long as you know the offset, which is 5.00. Many of us here use Chirp-Next and can provide the programming for you to get started. Just remember you must have a radio capable of transmitting and receiving those UHF frequencies for this all to work. In addition, some of the clubs will link their repeaters to others around their state or even neighboring states for greater versatility. For instance, from my house in Tucson, I can talk to people in various parts of New Mexico. Unfortunately, a large majority of us bought their radios a while ago and they cannot operate in this band. To be able to access this network would require an investment in another radio which may not be possible for financial or installation reasons. This is the major roadblock in my opinion to switching from the “race” frequencies to the FRS / GMRS bands for universal use.

I welcome questions or comments and I’ll be happy to dive into this further if the interest is there.

This post will concentrate on sound. Sound you say? Yes, the sound from your intercom, radio, and whatever else you listen to like music or turn by turn directions, etc. One of the most overlooked parts of your high dollar install is the sound you actually hear (or don’t) from the setup.

Many choose some type of headset, which is great. They all have some type of passive outside noise attenuation and the speaker quality isn’t too bad for almost everyone with the exception of true audiophiles who are never satisfied with the quality of the sound. LOL. The mics are of decent quality and are very reliable. If not wearing a helmet is your choice, these headsets fit the bill nicely. Over the head or behind the head types are user preference, and I am partial to the behind the head style, especially if you wear a hat while driving.

But what if you wear a helmet? This is where I will suggest some things to make the experience better. The big guys (PCI,Rugged, etc) all have helmet kits. Some call them “enhanced or alpha bass” whatever. I dare say this is marketing hype. Why? All of these speakers will get the sound to your ears but the sound your ears perceive will always be sub-standard. Why? You always have to contend with the background noise from wind or the car itself. SO, we turn up the volume to an appropriate level for the conditions we ride in to overcome that noise. Is there a better option? Absolutely! It’s called ear transducers, which is just the technical name for ear buds. If you were to look closely at all forms of racing, like NASCAR, IMSA, etc, you will see the drivers put in their custom molded earbuds first, then the fire retardant hood, and then the helmet. Once the helmet is on they connect the earbuds to the helmet jack. Then they connect the helmet cord to their vehicle. Having a custom set is the gold standard, but can be a hassle and is pricey. In order to get these, a visit to the audiologist is mandatory. Sure, you can get a DIY kit and try but it never works out as good as when a professional makes the molds. No sense wasting time and money with the risk of poor performance when the professional will guarantee a perfect fit or they will do it again at no charge. Then the molds get sent to your choice of manufacturers to have them custom made for you. All this takes time and there are so many choices of transducers it can be rather confusing. Not for me, thanks.

So, what are the alternatives? A quality set of ear transducers that have some sort of foam tips that seal in your ear and are comfortable enough to wear all day. Your choice should take into account that the tips should be available in any size to match the user’s ear for best sealing and comfort, be easily replaced, and are easy to procure. They should be constructed of quality materials (especially the cords) and most of all, sound good in your ear. There are all kinds of these offerings out there but I will concentrate on the best one I’ve found. Let me first say that I am in no way affiliated with the company and receive absolutely no compensation for promoting their products. What I will say is that I have used their products in various applications from aviation to tactical and off-road. They have never disappointed.

Before I reveal the product, let me make a few comments about why I believe this is a better alternative to helmet speakers. First, when trying to block out the background noise, you have to raise the volume, sometimes higher than it should be, which can cause distortion in the ear. Distortion makes the conversation or transmission hard to decipher. It makes the music less pleasant to listen to when the frequencies are all jumbled together. By using these earbuds, the frequencies from your audio device go directly into your ear and are attenuated to almost the same degree as just wearing foam earplugs, like on the shooting range, etc. This allows you to perceive the audio without the background noise and allows you to turn the volumes down significantly, eliminating distortion and actually being able to enjoy the audio. Once you get the hang of using these and keeping the cords from snagging on your belts or chin strap, they are fantastic in my opinion. True racers know this and they have access to all the best equipment. We can too, for a fraction of the cost of custom molds. Now for the reveal:

The actual part number is CEP 508-SR

The advantage to these is the quality cabling and the quality transducers. They are the only company I found that uses “COMPLY” eartips, same as the military. They simply thread on with a quick twist and last longer than any other product I’ve ever used. It has a standard 3.5mm stereo jack on the end and the cable length is more appropriate (shorter) than standard earbuds, making it easier to get them out of the way to prevent snagging.

Now the downside, because everything has a downside. First, their website is like something from the 80’s. Terrible. You seriously have to call to order them. Second is price. These run about $100.00 shipped with a sample of tips. Once you try them and figure out the size that fits you best, you can order the replacements from them or they are available in several other places online.

OK, now that we discussed the benefits of earbuds vs helmet speakers, you can save a few bucks when you order the helmet kit as Rugged sells just the mic boom with a 3.5mm female stereo jack. I believe PCI does as well. I have found using the Rugged helmet mount works very well for the install and I even went so far as to drill and tap a small hole in the mount and used a clamp to secure the jack where you can easily feel for it with the helmet on and it won’t just flap around. All in all, a nice clean installation that works very well and is comfortable to use for even the longest rides.

I hope you found this informative.

This post will be a follow up on coax cable. I thought it would be prudent to bring this up considering several members have posted freezing issues with their digital displays especially in their 21 and up cars.

When I upgraded from a handheld with an external antenna to a more powerful mobile radio (25 watts) I was able to actually experience the dash freeze. It was the first time I had seen it happen in person. I was stunned because with the handheld it had never happened to me in the first thousand miles since it was new.

I went back and basically checked everything I could to try and diagnose the issue with no luck. It was still happening intermittently so that made it more difficult to nail down the culprit. No being one to let a problem go unresolved, I dove in deeper. I realized that the antenna cable I was using was typical RG58, which came preinstalled on the NMO mount I installed in the car when it was new. I figured cable loss had to be a factor and decided to replace it with LMR-195 (which I referenced in prior posts). I was careful to route it the same as before (for verification purposes) and took great care when soldering the connectors on. I went back and checked the SWR, which had actually gone DOWN a bit (0.2) to be exact on both VHF and UHF. It was already at a more than acceptable level before the cable change so I had no expectations of a better result. I figured some benefit for the cost was a win-win. After getting everything back in its rightful place and secured properly I had the opportunity to go ride the following week. Hoping for the best I paid very close attention to the display and there were no issues at all. It should be noted that I didn’t spare the transmit time during the ride as I wanted as good a test as I could get. Fast forward 3 more rides and the issue has disappeared. I’m convinced the cable selection and quality made all the difference.

Recently I had a guy approach me asking if I had any problems with my display (since he saw I had a radio). I explained that I had, and how I fixed the problem. He was reasonably local to me and I offered to do the same to his car. His car had a more powerful 50 watt radio. I gave him a shopping list and when he showed up at the house we replaced the cable, routed it the same as my car and tuned the antenna. He called last night and told me he now has 3 rides on his car since we did the work and was happy to report the problem resolved. His call is what prompted me to add this post.

While all electronics are required to be able to reject RFI, the standards are somewhat subjective. Based on my experience in these 2 instances, I reaffirm my statements in prior posts about the specs and quality of the cable you use in your installation matters, especially in the newer digital dash cars.

If you are one of the unlucky owners to have a freezing dash and are running a radio, I recommend you consider replacing that RG58 cable out for some LMR-195.

does it make a difference if the base mount is below the plastic body like this
I can't install it up high as it will get removed from low hanging brush
And Yes I Know it's not a Can Am

So today I thought I would post about Radio programming, since I was doing some a little while ago.

Wait, what, you have to program your radio? Yes absolutely! In most, not all, cases, you will need to either program a blank radio or add / reconfigure / change the frequencies you have in your radio. For instance, those who bought pre-programmed radios from the big 2 suppliers (PCI and Rugged) have changed their programming over the years. If you have a radio that’s, let’s say, older than 2020, chances are your programming is out of date. Race teams come and go and there is always someone new. If you want to be absolutely sure you have the latest programming so you can communicate with anyone in your riding group, keeping up with this is essential.

First, a little about the programming itself. ALL radios are considered “software defined” radios, meaning they must be programmed to work and require a PC to do it. This means you must have the software that works with YOUR radio as well as the programming CABLE to work with your radio. Luckily CHIRP-NEXT is here to help. If you have never heard of CHIRP, it is a free, open-source programming software that works on hundreds of different radios. You can Google search the models it will work with to see if this is an option for you. If not, RT Systems is the go-to source for user friendly programming software for most of the radios not serviced by CHIRP. That software does have a cost but comes with a foolproof programming cable. A note on programming cables THEY ARE NOT ALL CREATED EQUAL! Be sure you purchase one that has an FTDI chip in it so you don’t have to worry about finding a driver for it. Believe me, this can be a real hassle.

Now that you have either downloaded CHIRP or opened your RT Systems software, what’s next? The very first step is to download from your radio, which contains all of the frequencies and settings pre-programmed into your radio. This is your configuration file. SAVE IT ! You might need it later if you do something wrong and have to start over. Now comes the fun part, the frequency list. The major suppliers all have a generic frequency list and they are NOT the same. While some of the frequencies they have are common between them, they each contain some differences. To be sure you have the best of both worlds, PCI publishes their list on their website. Rugged does not but there are other ways to get it. There are a few sites online that have the list for you. Google is your friend here. Print everything out for reference. Open your configuration file then immediately save it as something else for starters. This will ensure that the uncorrupted configuration file remains intact. Now, start entering the frequencies on the list EXACTLY as they are written. Be sure to keep the naming the same as well. Yes, there are quite a few in the VHF band. I suspect that there are over 200 in total but don’t quote me. It’s not difficult but it is time consuming. If you’re lucky, “someone” has a list already made for you that you can copy and paste. Bear in mind, both Rugged and PCI have their “own” channels and having both is an advantage as long as you have enough memory in your particular radio. If you don’t, leave out the “proprietary” channels and concentrate on the race teams. You can always add at the end.

If you have a dual-band radio, you should separate the frequencies as you go. For example, all of the VHF frequencies occupy slots 1-100 and then the UHF from 100. The UHF frequencies don’t take up much as there are only 21 FRS/GMRS. A few of the GMRS channels are repeater channels so they will require different transmit and receive frequencies. We can cover that later if there are questions or interest.

Once you are finished, be sure to save the file as something you will recognize later should you need to update or change. Now that you have your programming complete, you will need to send it to the radio. Your computer uses different COM ports so you might have to change that setting to get it to work. We can answer questions about that as they arise.

I hope this helps a little for those who have never ventured into this before. I urge those with older radios to update your programming to the latest versions so when riding in a group you have the correct frequencies. When all else fails, there are several frequencies that have never changed over the years, like Weatherman, BFG, etc. I’m sure there will be questions and comments. I’m not familiar with every single radio out there but I’ll do my best to help.

Ok let’s talk about the amateur frequencies. Stay off of them ! Hams are, by nature, very protective of their frequencies and take great pride in having the ability to “home in” to the offender. They have the ear of the FCC so stay away. That said, it’s actually very easy to be respectful. The amateur VHF frequency range is 144.00 - 148.00 MHz. All of the race frequencies are above 150 MHz. And end around 158.00 MHz. Ever since the FCC cracked down hard on Rugged, both they and PCI have gone to great lengths to “license” their programmed frequencies and have done an excellent job of publishing what areas around the country specific frequencies can and can’t be used. Kudos to them with one exception. According to them (PCI and Rugged) you are only licensed to use their frequencies when you are using one of THEIR radios. Hogwash I say. Exactly what way will the FCC determine if I am using one of their radios? In short, they can’t. Enough said.

HOWEVER……the frequencies we use are, in fact, individually licensed by multiple entities all over the country for various legitimate business purposes. Intentional interference with the legitimate use of said frequencies is a definite no-no. The key word here is intentional. IF you were using a frequency while you were riding and someone called back to you and informed you that they were the licensee of that channel in that area, you SHOULD apologize and change your frequency immediately. If you don’t, and get caught (maybe, maybe not) then the FCC could prove intent and now the trouble begins. Fines are stiff. Now, in the real world, the largest majority of us ride in areas that are far removed from areas where there might be an issue unless you’re running a radio with some serious power from a high point within line of sight to your downtown metropolis. In short, be respectful and you should be just fine. Even PCI and Rugged put a disclaimer on their frequency lists about licensing to avoid culpability.

In an effort to quell the problems associated with “sharing” these VHF frequencies, the FCC makes several other to be used. They are “MURS” or Multi Use Radio Service or the “Business Band” frequencies set aside for unlicensed use. They do have power limits so be careful when you use these so as not to piss off the local department store employees as this was the intended use for this reserved frequency range.

I have discussed the FRS (Family Radio Service) and the GMRS (General Mobile Radio Service) in prior posts and am a big fan. These are gaining popularity among the off-road crown in place of the age old CB radios and are more popular in the east. They are in the UHF spectrum and are an excellent choice for communications.

This is a very sensitive subject here on this forum and in other Off-Road forums. I invite comments on my post as always.