Tuesday, October 27, 2020

Guest Post: Is GMRS For You?

GMRS stands for General Mobile Radio Service and is a licensed service in the USA that shares some of the FRS (Family Radio Service) channels but allows use of radios and antennas that give you more range. In this article I will outline the steps to get a license, as well as talk a little bit about what equipment is available. 



Why GMRS?
Unlike Ham Radio, a GMRS license requires no test; just 3 questions on an application and a $70 payment. The license is good for 10 years and covers you and your immediate family all the way down to your grandchildren, including in-laws! You can conduct a family business using GMRS (so it’s good for a ranch or farm), but your employees are not covered; they would need their own license so they can talk with you. Many Public Service organizations such as CERT or REACT also use GMRS. With this license you could have you our own repeater if you wanted (or form a group to pay for putting one together)

How Much Range is "More"?
Mobile and Base Stations are up to 50W, but GMRS uses repeaters like you have with Ham. So depending on your terrain, you could communicate 5-10 miles between your house (with an outdoor antenna) and your car while you are out; with a repeater, that might be 50 miles. 

How Do I Get a License?


Get a FRN (Federal Registration Number)

If you already have a Ham License you might have a FRN already. If so, skip to “Apply for a License". 
  1. Go to https://apps.fcc.gov/coresWeb/publicHome.do
  2. Click on Register.
  3. Answer the questions. 
  4. Register as an Individual as GMRS licenses are only good for Individuals.
  5. Wait for the email with your FRN
Apply for a License
  1. Go to https://wireless2.fcc.gov/UlsEntry/licManager/login.jsp and log in.
  2. Click on Apply for a License (on the left hand column).
  3. Choose the bottom choice in the box (ZA - General Mobile Radio Service)
  4. Answer the additional questions about whether you are exempt as NO.
  5. Answer the question about whether you have been convicted of a Felony.
  6. Review to make sure all your answers are correct. 
  7. Sign by typing your full name and answering the question about what your title is as SELF.
  8. Follow the link to Payment. Please note that it will take a few minutes for the invoice to show up in the system, so wait about 2-3 minutes before clicking the link.
  9. Wait a few days to get the License.
  10. Order your radios!

Radios


Do I Need a Handheld?
The answer to this depends on 3 things:
  1. Do you only need a range of less than1mile under normal circumstances?
  2. Do you have access to a repeater you can access with only a Handheld?
  3. Are you wanting to have a passenger communicate while driving?
If the answer to any of these is yes, then a handheld is for you.

GMRS handhelds can have more power than FRS handhelds as well as better antennas (FRS only allows for fixed , non-upgradeable antennas). GMRS handhelds are are channelized the same as FRS and follow the same plan, but many GMRS handhelds also allow you to use repeaters. 

The Btech V1 handheld is about $60 (about twice what an FRS radio costs) but has 5w compared to the 2w of the FRS, allows you to access repeaters, and allows you to use a better antenna.

When Should I Get a Mobile? 
(and how much power do I need?)
Are you wanting to drive and talk at the same time? Many states have laws on the books saying you can’t hold a cell phone while driving, and it's hard to distinguish a handheld from a cellphone while passing a cop.  

Mobile radios range from 5w-40w in the models available currently (unless you want to go to eBay and get an older Motorola or other brand that needs a special programmer), and prices range from $99 on the low end to $249 or so for the more powerful units.
  • Mobile radios in the 5w category, such at the Midland MXT105, tend to be direct only (no access to repeaters) and come with fixed or magnetic mount antennas. 
  • Radios of the 15w or 40w variety, like the Midland MXT115, have fixed or magnet mount antennas but also allow you to access repeaters. 
If you don’t want to drill a hole in your vehicle, a magnetic mount antenna will work for most uses. There are various “Gain” antennas available; many of them are short (6”) ¼ wave antennas, but you can get larger antennas (such as ⅝ over ⅝ wave) that are 25” or so. More gain generally means further range. 

In short, if you are going to be out in a vehicle and want to talk, get a mobile radio.

Are Base Stations Worth the Expense?
I’ve not found many, if any, dedicated base stations for GMRS. The most common way to build one is to take a mobile radio, add a power supply, and purchase a base station antenna and coaxial cable. 

Probably the most common use for this would be when there isn’t a repeater locally available and you need more power than a handheld would give you or need to be able to talk directly to a mobile or handheld out in the field. On some channels you can use up to 50w to do either.

Base station antennas go from little spikes that are 6” tall to giant monsters that are 11.5’ tall; it all depends on who you want to be able to talk to. For “around the 10 acres,” a simple spike mounted high and clear of buildings and nearby trees might be sufficient; if you need to be able to access a repeater 10+ miles away then you might need a 6 foot tall antenna; but if you want to talk directly to a mobile out in the field, you might need the 11.5’ monster. 

There are many kinds of “coax” cable out there, but for a base station you want a minimum diameter of 0.400” and to keep it as short as possible, as the losses inside the coax go up dramatically by length.

Repeaters 

Join an existing Group
There are some 1700+ repeaters in the US, many of which are open or private but you can join the group. Check out https://mygmrs.com/browse where you can search by state for repeaters around you. Joining a repeater group, or supporting an open one, means that you won’t be an unknown person (or family) when you need to use it. 

Like Ham Radio,  you want to be brief and to the point when communicating among your family during an emergency. Many of these repeaters have “Nets” where everyone checks in and verifies their equipment works. Some just have a net to chit-chat!

Buy Your Own Repeater
Let’s say that your family is all over the place and that you can’t tie up someone to act as a relay sitting at a fixed location (like a base station). In that case, the next step might be to buy your own repeater. A good antenna, coax and backup power are necessities for good repeater operation, so expect to spend between $600-$4000 for a repeater/antenna/coax.

There are 8 repeater pairs of frequencies you can use, and you want to coordinate such that you don’t “step on” someone who is already using a channel in your local area. Again, check out https://mygmrs.com/browse where you can search by state for repeaters around you, and listen a lot before you decide to buy/install a repeater.  

While there are a few low power repeaters that are easy to program and are good for “local” use, a higher power repeater will have to be programmed with a special programmer and “tuned” for the channel you choose. Getting a high, clear location that is able to “see” the areas you want to be able to operate is a big consideration.

Final Thoughts
Practice! In the middle of an emergency where your cellphones are dead isn’t the time to break out the GMRS radios for the first time. Instead, join a group of like-minded individuals and families.

I can’t stress enough that you need to practice! Send the kids off to play/explore with a handheld and use the radios to check in periodically; it will help them to understand how to use the radio as well as give them the discipline as to how to use them when needed. Go to the grocery store and practice using the radio to “ask for the thing you forgot.” Remember, cellphones may not be there when you need them.


Tom King

KA6SOX / WRJK601

2 comments:

  1. GMRS isn't much better for things here. Just that FRS and GMRS are mostly off the shelf and highly portable.

    A rough reality check for range is here:

    http://hflink.com/hfpack/radiorange/

    Handie-talkies on average can expect 1/4 of a mile to maybe as much 3-6 miles with the best gear. Base stations will extend the range out. Part of the problem is the RF propagation characteristics. CB's actually got better characteristics than anything, but it has actually long antenna requirements (That rubber ducky antenna won't get you much further than the FRS gear- electrically small) and eats batteries like candy- even a Lithium one because you're talking 5 or so watts within legal boundaries.

    So...is GMRS worth the trouble? In most actual prepping situations, you're not going to have a base station. You'll do good to have people with handie-talkies. They're all going to, unless you reach for Ham gear, going to be severely range limited.

    So, no, it's not worth it unless you're setting up a bit more than a survival situation

    ReplyDelete
  2. Once you start talking repeaters, etc. you're better off with the real gear- and understand it's use.

    ReplyDelete

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