All Activity

HOW MANY FARS??? One of the most asked questions about GMRS radios is “How many FARS?”. How far can it transmit and receive. Unfortunately, the question is someone meaningless as the answer is, “It depends”. Of the three primary factors, (power, antenna type and height) it is the height of the antenna by far that is the most important. It takes very little power and only the simplest of antennas to reach over 400 miles! While this topic has been covered before, most OPs make a mistake with the use of the earth's curvature equation. So here goes. Feel free to comment. The best example I could find on "How many FARS?", is from weather balloons which transmit in the 400 to 406 MHz range with an output power of LESS than 0.5 watts (60 to 250 mW) to a quarter wave ground plane receiving antenna. With a release point in Santa Cruz CA, the longest reception was ~750 km (466 miles) off the coast of Mexico. My personal best was 44 miles using a bubble pack Motorola Talkabout T7200 HT putting out 1.5 watts through an integral fixed antenna to a roof mounted J-pole antenna using Radio shack RG58 cable attached to a simplex repeater and a 4 watt HT. My view is that if you can’t hear with a FRS bubble pack radio in an open air, line of sight condition then there is some form of obstruction between the two radios. I consider that there are three types of obstructions. The first is the curvature of the earth, the second is a solid obstruction such as solid earth from a ridgeline, mountain, etc. to a reinforced concrete wall, and the third is vegetation, wooden structures, glass, human bodies, etc. The first two types of obstruction are absolute. You are not going to get a radio signal through no matter how much power or antenna type you are using. Only antenna height can solve the solid obstruction problem. It’s the third type of obstruction where antenna type, height and transmit power come into play. CURVATURE OF EARTH With an antenna height of 5 ft. above the ground that is flat you can transmit for 2.7 miles before the signal hits the earth from its curvature. But wait, if the other radio is also 5 ft. about the ground they also can transmit 2.7 miles for a total range of ~ 5 miles. These are the conditions for the normally stated 5 mile range of GMRS radios. The 7 miles that is sometime stated is a special case of both radios (~ 5 ft. above the surface) being over a body of water which slightly bends the radio signal giving a bit more range. Both cases also require open-air, line of sight conditions with both radios being at the same elevation. The condition that both radios are at the same elevation, which almost never is true, is why you can’t use these simple calculations for determining radio range from the earth’s curvature. In one YouTube video on FARS, the second scenario shown was with one radio located in Plankton (Elev. 922 ft) and the second in Melrose (Elev. 856 ft), OH. A distance of 4.6 miles apart. The reason you can’t use the above calculation of 5 miles horizon curvature range is that the town of Melmore is at an elevation that is 66 feet lower than Plankton even though it looks fairly flat. Not to get too much in to the specifics of the math, I take the difference in elevation (66 ft.) along with the height of the upper antenna (5 ft.) to compute a radio horizon curvature range, or 10.4 miles. I use this value as an approximation of how close I am to failing the curvature test. Don’t use GPS elevations as their accuracy is only +/- 60 - 100 ft.) For comparison purposes so one can better understand the importance of antenna height here are the earth curvature ranges for different antenna heights with a flat surface. (No consideration for the second radio antenna height above the ground). Use these values to help one determine approximate changes in antenna heights to reach the second radio. 5 ft. – 2.7 miles 10 ft. – 3.9 miles 20 ft. – 5.5 miles 30 ft. – 6.7 miles 50 ft. - 8.7 miles 100 ft. – 12 miles 500 ft. - 28 miles 1,000 ft. – 39 miles 5,000 ft. – 87 miles 10,000 ft. – 123 miles With my personal best I was ~ 4,500 ft. above the second antenna or a curvature range of around 82 miles. SOLID OBSTRUCTION Topographic features of the earth (the earth is seldom flat) are more important than the earth’s curvature in determining if you can communicate with another GMRS radio. To determine if you have any geologic solid obstructions you need to be able to construct a topographic/elevation profile using the USGS National Elevation Dataset (NED). You simply draw a line between the two antennas and have the software compute a profile. I use the software TOPO which is no longer available. You can also use Google Earth Pro to perform the same function. This will show you if you have an open-air line of sight or if the ground is going to obstruction the signal. Here is the profile from my 44 mile test sitting on Bandera Mt. and talking back to my house in Seattle. Easy peasy. To show you another example I was recently driving around the San Rafael Desert in SW Utah where there is no cell phone coverage. Computing various profile lines I was able to predetermine that if I set up a simplex repeater on a plateau near an easy access dirt road (the right-side or eastern line) I could communicate back to the hotel in Green River (38 miles away) from pretty much anywhere in the desert and some of the slot canyons in the San Rafael Reef which opened out onto the desert. A worthy undertaking as the soft sand made travelling somewhat sketchy. The profile line to the left (west) showed that the two radios could not communicate. Here are the results. This third example shows Google Earth Pro using the towns of Plankton and Melmore, OH. To see if one has any topographic issues simply draw a straight line (or place a straight edge on the computer screen) to see if you will intersect the earth. In this example the answer is yes, but check the elevation scale (7.5 ft) and by raising the upper antenna (Plankton) up to 15 ft. above the ground will allow you to communicate to the center of Melmore. It’s almost always best to raise the upper antenna for best chance of improved reception. Notice that there are a number of creeks and other low points that one will not be able to communicate into. I tried another profile line to see if one can communicate from the town of Plankton to the nearby #103 Highway. The answer is there is a low ridgeline (Elev. 935 ft.) that prevents this. By dragging the profile line you can find where the highest point is (the big red arrow). This is the location one would want to put up some form of a repeater if you wanted to extend the range of your radio. Semi-obstructions These are the types of obstructions where radio power and antenna type can help extend the range (FARS) of GMRS/UHF radios. Unfortunately, there are no formulas that I know off that will allow you to predetermine how many FARS a radio can transmit/receive under these variable conditions. Just don’t stand between the radio antennas and try to create as clear of a path between them. I’m sure many people here are much more knowledgeable on this subject than I am. Feel free to add to how many FARS a radio can reach.

There is a similar antenna from Diamond. It’s the NR240CA. https://www.diamondantenna.net/products/NR240CA The full spec’s are in this PDF file. https://www.diamondantenna.net/static/pdfdocs/NR240CA.pdf

I had to laugh..................... give these frequencies to the Hams? They will use them? Hams wont even use 6m unless the band opens up and sends their signal halfway across the country. I say, make a long range GMRS band. Regular citizens will put them to better use. I have sat here for quite awhile trying to find digital activity on 6m since voice is always dead. No repeaters, no simplex, nothing. I did manage to make one contact on FT8. The first and only contact since 1996. Since then, I haven't noticed even a fart of activity on 6m. So what makes anyone think Hams will make use of the 46/49 MHz band?

That’s right; the software works differently than Chirp. As others said click on the caret. Disregard Socialmisfit. In fact add him to your ignore list. He never has anything useful.

Alright my guys! I will take your tips and apply them when I get a chance this evening. Thanks. I’m thinking I didn’t double click the furthest right arrow or carrot as that’s not anything like the wouxon chirp or baofeng software that I’ve used.

Will Rogers never met you in person, either!

Using the YouTube video as a reference point, at about 17:20 in, you see the Radioddity software: If you double click on the "double caret" below the word "More" for the Channel you want to edit, it should bring up the window for changes: Does this work for you?

Yeh I can program it manually. I would like software to work though.

I did get the software to work. I had a problem at first, with getting the right driver. The only issue I remember with the software programming was with channel 39 which I had originally programmed for simplex using the buttons. I don't recall any issue with entering tones. Can't you change the tones using the buttons?

Ive been running it for 5 months or so and it’s been great actually. I’ve just been programming it manually which isn’t too bad. But I’d like to get the software to work if possible.

All that is understood. Apparently you didn't read or understand the OP and followup posts I made. I was trying something similar last night on a couple of old UV-5Rs that have RX problems and aren't as useful for normal operation anymore. Unlike the 5RM/K5+ those do have frequency range limits that can be adjusted. I was able to get one programmed with RX-only channels for GMRS plus normal TX/RX channels for 2m/440 and have only 2m/440 allowed in VFO. I tried an opposite approach on the other, making it as close to a certified GMRS unit (like the UV-5Gs I have) as possible. I wasn't able to come up with a frequency setting pair to block VHF in VFO (it has separate range limits for VHF and UHF). I may go back and try leaving the VHF frequency settings blank or set to 000.000. I can always do what I did on the other one if there's no solution to getting just GMRS.

try watching this video

Hey Negative Nancy, thats because you never meet anyone.. Nobody wants anything to do with you!

No one I have ever met in person has had any “luck” with that radio In General. It usually gets returned of filed in the round file in a few days.

Has anyone had luck using the manufacturer’s CPS (computer programming software) with the db20g? Program allows me to download from radio, and see the entire file, but it won’t allow me add PL tones no matter how I click the field? I’ve tried the keyboard, mouse and tried batch channel editing and nothing can be edited in the software other than the name of the channels. Am I missing something? Chirp is not supported yet with this radio far as I know.

there is a reason, can you imagine going to an ATM machine and spending an hour finding your language to proceed This is no joke,, the other day i was standing in line at an ATM an older guy in front of me using the machine starts cursing out loud. I said ' what are thy out cash' he says "F**K no, this G*D D*mn machine, I can't read spanish bla bla bla.. . He strugles to get his card out, he finally does, he storms inside the bank... OK, my turn, first screen says select 'yoour language'.. I guess he selected the wrongh one

The 5RM is a ham radio, and there is no "type certification" as such. Amateur radio licensees aren't limited as to what equipment they can own or use, only what frequencies they can transmit on. I just don't program in any frequencies which are outside those authorized for my technician license.

Welcome to the club, been there, done that... getting older is not what it is cracked up to be that's for sure.

Something like this is what I was wondering about setting up. Our area can not be covered with handhelds in the entire area (mountains/terrain) but the repeater now in use can be heard in all locations. We're using it for assisting EM/Storm Watches, etc. The current repeater is on top of a mountain 2,184 elevation. In one direction a handheld can work the repeater from 28 miles away without a problem, in another direction 7 miles away it is impossible to use a handheld.

That 2x4 is a pretty remarkable antenna. I get good performance on GMRS, 2m, and 70cm, and the SWR/Smith graphs are nearly perfect on MURS and 1.25m as well. The graphs don't show how well an antenna can transmit on a given band, and I'm a little skeptical that one antenna can perform well on 5 bands, but at some point, I'll try it on 220 and see what I get. It would be great if it could do 220, because that would mean I can put the Anytone tri-band radio in my little car and use only one antenna. There are tri-band antennas out there, but so far, I haven't found one that gives me good SWRs on 140, 440, 220, and GMRS. I don't want to give up GMRS, so I'd need another antenna for it. I don't care much about MURS. It's nice to know I have the capability if I need it, but I've literally never used it, and I'd give it up for good performance on the other 4 bands.

My understanding of "official language" is that it will be required on all government documents, web sites, etc. and official documents can't be required to be provided in other languages. As far as I can tell, it won't prohibit government sites from providing translations in other languages as long as an English version is provided. Which, TBH, seems pretty reasonable to me. Since TV stations, radio stations, etc. aren't usually government-run, they'll be unaffected. Since GMRS and amateur radio are mostly private endeavors, I can't see the EO affecting our radio usage. Nobody owns the GMRS channels, and short of a change to FCC regulations, nobody can dictate to me that I can't use whatever language I like. A repeater is a bit different. Since it's privately owned, I support the owner's right to decide what language users must speak. I'm not sure how you'd enforce that, but in theory I support it.

My guess is that it's a holdover from military and commercial radio where fixed stations communicating with other fixed stations can be pretty common. Less so now, with modern equipment, but at one time, a lot of -- usually remote -- military installations had radios that only talked to the "mother ship" somewhere else. I think FCC just carried over the idea and the language to GMRS where it's rarely applicable.

The radials arrived in the mail yesterday, so I'm ready to stand up the mast whenever I can wrangle some help. A couple of friends who are GMRS users have volunteered to help; we just need to find a day we're all available. My location isn't ideal for a repeater, but it's pretty good, and I'm not in a position to rent space on a tower. If my calculations are correct, 50' should get me over the hill to my southwest, which is the only major obstacle for a considerable distance. If I can get over the hill, I should be able to reach the family farm west of town. East and north will have excellent coverage, but my biggest goal is to reach the farm.

When I was restoring a lot of old military firearms, I bought that stuff by the bucket. Removing the barrel from a 70 year old M1 rifle can be...interesting. Much cursing was involved. When I put the rifles back together, barrel threads and other metal-to-metal screws got some anti-seize. So, I'm right there with you on that.

This might be a bit late but hopefully will help someone. On the mike scroll through the channels. When you get to the repeater channels you will find double channel entries. On is simplex and the other is the repeater channel. Once there match up the channel and ct code in the manual. Then using the menu system on the correct freq you will be able to set the rec and tx. Best to find that info and write it down before setting the numbers.