MURS frequencies

[mmckenna]

Do you think they are disabling all the functions that would make them legal to use as a ham radio? I know the Kenwood TM-218a will only transmit on the amateur radio band range of 144 to 148mhz because I was looking into buying one myself for the cheapest price I could find it to save a buck and to start to learn amateur radio while obtaining a Tech license. I know they can be modded to Tx outside this range, but that then makes the radio non-compliant with the FCC. Do you think this is happening with the gear companies that are selling these radios and how are they getting around the legality?

I'm not familiar with the rules in Mexico pertaining to commercial radio use, so I can't really comment on what the Mexican government would say. I know what the US FCC rules are, and modifying an amateur radio that does not have Part 90 type certification to work on Part 90 frequencies is absolutely against the rules.

I've read a lot of articles about off road driving and how it's pretty common for modified amateur radios to be used. I've looked up the FCC licenses used for the races, most specifically BFGoodrich and a few others, and I understand how they are licensed in the USA. I have no idea what their licensing agreement is with Mexico. If the individual companies (BFG, etc) hold the license, then they are responsible for who they authorize to use it. That means, according to the FCC rules, that they could have their license suspended if someone was operating a modified amateur radio on company frequencies with their OK.
I've also seen where companies that specialize in "racing radios" will sell you a pre-modified amateur radio loaded with the company channels.

There are a number of issues with this that I won't dive into here.
I know it happens, and I know that it's pretty much ignored. You were, however, asking about the licensing/legality side of all this. I won't tell you it's OK to do this, because it isn't. I'll add that the odds of getting caught are pretty slim. Just trying my best to explain the FCC rules and how they apply here in the USA.

Your bandwidth comment is very interesting. I'm still learning all this bandwidth science so bear with me. Last night I went into the menu of my Baofeng UV-82hp and found bandwidth on menu 5. The book says that NB is 12.5khz and that the WB is 25khz. (I don't even want to ask about the deviation, but I will eventually. ha ha)

It gets a bit deep with this. There is the "channel width", the width of the individual lane on the "highway" (good analogy). Then there is the actual radios emission width, which is something less than the actual channel width. The idea is that you need to keep all your emissions within the channel boundaries to keep from interfering with adjacent channels. That is why the 12.5KHz width channel requires an emission of 11.25KHz, you want to keep everything in your own "lane".

Deviation is just the amount of change from the center frequency used to modulate the signal. On FM, there is the center frequency and then there is the emitted signal which includes the amount of deviation from this center point necessary to carry/transmit the audio signal.

Am I correct in that I am starting to think that one of the bandwidths, NB or WB is capable of reaching out and doing more things? For example you could Rx and Tx with WB on a frequency that is mandated by the FCC to only be used for NB hence making it illegal?

Thanks again everyone!

Yep, it would be illegal. Think of driving an oversized load down a busy urban highway. Your wide load would spread across more than one lane. Same thing happens in radio. The channels are designed for a certain bandwidth. Operating with more bandwidth on the channel means your signal would spread across into other "lanes". Those other "lanes" might be carrying Fire Department radio traffic, Police traffic, etc. You could possibly interfere with someone else's channel.

 

[ke6gcv]

No, because -YOU- are not licensed. The company is licensed and only the licensee and the authorized users can operate under the license. If the licensee allows you to use radios under that license and you are following all the rules that apply to that license, they you are OK. Bringing in your own radio and transmitting with it isn't automatically OK just because you are on the clock.

I have several licenses here at work that I am responsible for. I would happily turn in someone who works here if they suddenly showed up on one of the systems I'm responsible for without my/our OK.

I've had to warn people off our systems before because they assumed they were automatically authorized.
We have a police department and a fire department. One of our plumbers can't just decide to use those frequencies on his/her own radio simply because he works for the same agency as the fire/PD.

I was not aware of the legality of doing that. I have been educated. I thought it would be OK so long as you're working. No problem! Far be it from me to advocate anything that is considered illegal.

Thank you, mmckenna, for the information!

 

[mmckenna]

No problem.
FCC rules can be tough to understand and a lot to wade through. If you are ever bored and need help falling asleep, you can read them here:
https://www.fcc.gov/general/rules-regulations-title-47

Part 95 for GMRS/FRS/MURS/CB, etc are a good read for anyone operating under those parts.
Part 97 should be a mandatory read for anyone with an amateur radio license.
Part 90 is a lot to get through, but there is some useful information.
More importantly, it's necessary to understand that there are other rule parts that apply, not just the ones for the respective services. Reading Part 1, 2 and 15 is a good idea. Part 2 covers a lot of legal issues that are not covered in other sections, yet they still apply.

Anyway, the piece of Part 90 that covers this specific question is:

§90.403 General operating requirements.
(a) Licensees of radio stations in the private land mobile radio services shall be directly responsible for the proper operation and use of each transmitter for which they are licensed. In this connection, licensees shall exercise such direction and control as is necessary to assure that all authorized facilities are employed:
(1) Only for permissible purposes;
(2) Only in a permissible manner; and
(3) Only by persons with authority to use and operate such equipment.

This one applies too:

§90.427 Precautions against unauthorized operation.
(a) Each transmitter shall be so installed and protected that it is not accessible to or capable of operation by persons other than those duly authorized by and under the control of the licensee. Provisions of this part authorizing certain unlicensed persons to operate stations, or authorizing unattended operation of stations in certain circumstances, shall not be construed to change or diminish in any respect the responsibility of station licensees to maintain control over the stations licensed to them (including all transmitter units thereof), or for the proper functioning and operation of those stations and transmitter units in accordance with the terms of the licenses of those stations.

(b) Except for frequencies used in accordance with §90.417, no person shall program into a transmitter frequencies for which the licensee using the transmitter is not authorized.

^^^^^^ This last one here is often ignored. Basically it means you cannot have a bunch of frequencies programmed in (capable of transmitting) that are not authorized under the license. It also means that if someone showed up with their own radio and had a bunch of other stuff programmed in that wasn't covered by the employers license, the company could theoretically get busted.

Of course we all know that for the most part FCC rules get ignored. FCC is notoriously lax on enforcement, and it's unlikely anyone would know unless there was some really blatant violation going on. None the less, they are valid laws.

 

[cmdrwill]

mmckenna has summed it up very well.Part 90.427 B especially.
FCC may be lax on enforcement, but when they do strike fines range from thousands to over a a million.
Many so called radio shops have been fined under 90.427B.

 

[kixntuff]

Yep, it would be illegal. Think of driving an oversized load down a busy urban highway. Your wide load would spread across more than one lane. Same thing happens in radio. The channels are designed for a certain bandwidth. Operating with more bandwidth on the channel means your signal would spread across into other "lanes". Those other "lanes" might be carrying Fire Department radio traffic, Police traffic, etc. You could possibly interfere with someone else's channel.

Well it seams like you did an excellent job explaining this matter of NB vs WB and I think I am smelling what you're stepping in. Now lets see how well I understand it. So lets take MURS frequency #1 151.820. If Joe Blow tunes his radio to 151.809, he would still legally be operating within the FCC limits of MURS freq #1, correct? That's 11.25khz below center at 151.820mhz.

Let me one up that question. If Joe Blow was Tx'ing at center of MURS frequency #1, Could Chuck Knuckles Rx him if his radio was tuned to 151.809Mhz?

Sorry I had to ask this again, but I'm really interested to know if I understand this correctly.

Thanks!

 

[jwt873]

For what it's worth, there is no 'tuning' of MURS radios. If you want to use the MURS service legally, you need a radio that is government approved for MURS use. (I don't know about Mexico, but you do in the US) . These radios have fixed channels, bandwidth, and power settings which makes it impossible to change anything channel wise.

You can pick up a radio like the Baofeng UV-5R FM VHF radio off of eBAy that will happily work on the MURS frequencies, but... it would be illegal to use it on the MURS frequencies.

 

[mmckenna]

So lets take MURS frequency #1 151.820. If Joe Blow tunes his radio to 151.809, he would still legally be operating within the FCC limits of MURS freq #1, correct? That's 11.25khz below center at 151.820mhz.

No. 151.820 is the center frequency of the channel. Think of that as the center of your lane. Your vehicle rides down the center of the lane but still has to be inside the lane. If the radio was set to transmit on 151.809, it would be spreading across into other lanes (channels).

If you were using some super narrow bandwidth digital, you might be able to make it stay inside the channel, but those sorts of emissions are not permitted on MURS.

Let me one up that question. If Joe Blow was Tx'ing at center of MURS frequency #1, Could Chuck Knuckles Rx him if his radio was tuned to 151.809Mhz?

Mr. Knuckles would hear something, but not intelligible. Think of an old FM broadcast receiver where you actually had a knob and a dial. If you were not tuned right on the center of the station, you'd hear crackly static, muffled sound, etc. Chuck needs to get his radio checked out......

 

[kixntuff]

No. 151.820 is the center frequency of the channel. Think of that as the center of your lane. Your vehicle rides down the center of the lane but still has to be inside the lane. If the radio was set to transmit on 151.809, it would be spreading across into other lanes (channels).

If you were using some super narrow bandwidth digital, you might be able to make it stay inside the channel, but those sorts of emissions are not permitted on MURS.



Mr. Knuckles would hear something, but not intelligible. Think of an old FM broadcast receiver where you actually had a knob and a dial. If you were not tuned right on the center of the station, you'd hear crackly static, muffled sound, etc. Chuck needs to get his radio checked out......

Got it. So you much Tx and Rx in the center lane. So basically when the FCC says MURS # 1 is 151.820 @ 11.25Khz bandwith. All they're basically saying is that you better not be Tx'ing outside the 11.25Khz bandwidth or we will consider this illegal because you might bleed into another frequency. Is this right?

Here is an Article that the main radio man called the weatherman posted up about radios in Baja. He speaks to this bleed over and illegal modifications to amateur radios used for racing. He also works for one of the main radio equipment companies that supports the race. He speaks to dialing your radio in-between frequencies which I assume is dialing in a frequency that is to close to the edge of the lane and will cause to go into the other lane. It also speaks to some of the rules everyone has to abide by down there. Apparently they do pay the Mexican government some money during the race.

http://www.mattsnook.com/baja500/score2009files/WeathermanSpeaks.pdf

 

[mmckenna]

Got it. So you much Tx and Rx in the center lane. So basically when the FCC says MURS # 1 is 151.820 @ 11.25Khz bandwith. All they're basically saying is that you better not be Tx'ing outside the 11.25Khz bandwidth or we will consider this illegal because you might bleed into another frequency. Is this right?

Exactly.
Deviation outside the channel width is what they are trying to stop. By using the same channel center and the correct amount of deviation, you'd stay inside your lines. Wander off the center (misaligned transmitter) or using too wide a bandwidth (using 25/20KHz instead of 12.5/11.25KHz) would cause interference to adjacent channels.
Sort of like driving in two lanes at the same time. Someone is going to be ticked off....

 

[nd5y]

All they're basically saying is that you better not be Tx'ing outside the 11.25Khz bandwidth or we will consider this illegal because you might bleed into another frequency. Is this right?

Different radio services and types of radios have frequency tolerances specified in the FCC rules.

That means that in addition to the bandwidth limitations mentioned previously, your carrier frequency can't vary more than a certain percentage or parts per million of the assigned frequency. At MURS the adjacent business channels are 15 kHz away. If you were 11 KHz off frequency you would be in violation and probably cause interference to adjacent channel users.

I don't know what the tolerance is for MURS off hand but it is probably something like 2.5 or 5 ppm which means you can't legally be more than about 0.375 to 0.75 KHz off frequency.

 

[mmckenna]

Here is an Article that the main radio man called the weatherman posted up about radios in Baja. He speaks to this bleed over and illegal modifications to amateur radios used for racing. He also works for one of the main radio equipment companies that supports the race. He speaks to dialing your radio in-between frequencies which I assume is dialing in a frequency that is to close to the edge of the lane and will cause to go into the other lane. It also speaks to some of the rules everyone has to abide by down there. Apparently they do pay the Mexican government some money during the race.

http://www.mattsnook.com/baja500/score2009files/WeathermanSpeaks.pdf

That's a pretty good document. A few errors on the technical side, but good enough.
I've read a few things about "Weatherman" a few times before, including how he does his mountain top setup. Pretty interesting to read up on that stuff. Glad to see that SCORE is trying to keep things legal.

Unfortunately many amateurs and others ignore the reasons behind not using modified amateur radios. It can be a pretty hot topic when it comes up on this site. Some fail to understand how their actions can impact others. Some think the rules do not apply to them. Others think that in an emergency, anything goes.

 

[kixntuff]

That's a pretty good document. A few errors on the technical side, but good enough.
I've read a few things about "Weatherman" a few times before, including how he does his mountain top setup. Pretty interesting to read up on that stuff. Glad to see that SCORE is trying to keep things legal.

Unfortunately many amateurs and others ignore the reasons behind not using modified amateur radios. It can be a pretty hot topic when it comes up on this site. Some fail to understand how their actions can impact others. Some think the rules do not apply to them. Others think that in an emergency, anything goes.

I can't say thank you enough for the explanations you all are giving. I take coms very seriously and do not want to be "that guy" down there if I do have to go with a modded mobile unit. If I do have to go modified I want to understand how my actions can effect others. I understand the etiquette and how important it will be down there to only listen to weatherman and not transmit to him unless absolutely necessary. As far as simplex communication from rider to chase vehicle. The chances of that happening are slim because he would only use it if the sat phone was not working and he would have to be within range. Chances of being within range are slim to none. I've tossed around tapping into the open repeaters down there on the amateur radio band for the week, but to much is unknown to prepare ahead of time and probably not worth the risk. We are out in the middle of the desert and human contact is very dismal if at all for most of the race. However, if there is a lot of local traffic on them I don't want to piss anyone off. Do you guys have any recommendations to picking a business band frequency and avoiding a lot of the other race team traffic down there? I am supposed to call and ask if PL tones are legit to use for simplex coms, but something tells me we can't use those either. Last, would anyone have a good recommendation for a mobile unit that does not need to be modified to Tx on business band and that one could use for amateur radio coms here in the states for under 200 dollars. I'd go with used equipment also if I knew what to get. I want equipment that will be able to filter out all the traffic that will be had during the race that supposedly the modded radios can't do as good.

Thanks,

Kix

 

[mmckenna]

I can't say thank you enough for the explanations you all are giving.

Always happy to help out any way I can. Running that race sounds like quite an experience. Good luck to you and your team.

Do you guys have any recommendations to picking a business band frequency and avoiding a lot of the other race team traffic down there? I am supposed to call and ask if PL tones are legit to use for simplex coms, but something tells me we can't use those either.

Honestly, if I was doing this?
Low band VHF. Or HF (2-30MHz), but getting a reliable HF radio set up on a motorcycle would be difficult.
California Highway Patrol uses Low Band VHF for most of their voice traffic. Works well over long distances, bends around hills well and can be pretty impressive on simplex. Trouble is a suitable antenna for low band VHF is going to be bigger than would probably be comfortable on a motorcycle. Off road it's going to be even worse. You'd probably be looking at a 4 foot long whip at minimum. That will take a beating off road. There are hand held low band VHF radios, but the antenna limitations make it tough. On a chase vehicle, adding a 1/4 wave whip antenna or a base loaded whip isn't much of a problem. They are usually a bit shorter than a CB antenna. A low band mobile radio is going to be heavy to carry on a motorcycle, so a portable/hand held radio is going to be the best option. Probably not a good solution for a cycle, better suited for a buggy or truck. Anyway, you'd really probably want to have the interoperability with Weatherman and others, so I'd stick with VHF.

Other than that a satellite phone is probably your best bet.

Last, would anyone have a good recommendation for a mobile unit that does not need to be modified to Tx on business band and that one could use for amateur radio coms here in the states for under 200 dollars. I'd go with used equipment also if I knew what to get. I want equipment that will be able to filter out all the traffic that will be had during the race that supposedly the modded radios can't do as good.

Thanks,

Kix

Hard to be a used Kenwood or Motorola mobile. I've got a few Motorola CDM model radios.
CDM-750 is a 4 channel radio. I've purchased them for as cheap as $75. VHF versions will cover 136-174MHz. I've got some running a combination of amateur radio 2 meter band an VHF commercial stuff. No LCD display.

CDM-1250 is a 64 or 128 channel. VHF models have same coverage as above. I've been purchasing these for $150-200. Nice LCD display.

CDM-1550 is a 160 channel. I've got one of these in my personal truck.

Programming is the costly part. Software is only legally available from Motorola.

Many of the Kenwood radios are a good choice. Often cheaper than Motorola's and the programming software is cheaper, too.
A TK-790 is a good VHF mobile. TK-7180 or NX-700 would be a good choice too.
TK-790 does 146-174 out of the box, but they can be stretched down to 144MHz. Available in 50 or 100 watt versions.
TK-7180 and NX-700 are cosmetically the same radio. 7180 is analog only. NX-700 is analog and NXDN/NexEdge digital. A bit newer than the 790, but a smaller radio.

Any one of those would be a good choice. On the used market it's kind of tricky to find a good one. Some risk involved buying used, but I've had good luck so far. All of them will cover the 2 meter amateur radio bands just fine, as well as legally working on the commercial stuff.

Key to getting the most out of your radio is to pay close attention to a really good antenna system. Buying a $200 radio and then ignoring the antenna would a bad idea. You don't have to spend a fortune on an antenna, but you should make sure you get a good name brand and have it properly installed and tuned. It'll really make a big difference in performance.

Don't even think about magnetic mount. If you are not willing to do a proper antenna installation, best back away now.

 

[ecps92]

Talk to the RF Coordinator for the event. :roll: Something this large they (HIBGIA) Have Been there Before and have established contacts to get authorized

Authorized US Frequencies are one thing for within the US&T not within another Country
Authorized MX Frequencies are not the same as those in the US&T (United States and Territories)

I doubt they have restrictions on PL tones. PL only masks you from hearing other users on the same channel (When for a properly programmed/installed radio) when the Microphone is On-Hook

I can't say thank you enough for the explanations you all are giving. I take coms very seriously and do not want to be "that guy" down there if I do have to go with a modded mobile unit. If I do have to go modified I want to understand how my actions can effect others.

Do you guys have any recommendations to picking a business band frequency and avoiding a lot of the other race team traffic down there? I am supposed to call and ask if PL tones are legit to use for simplex coms, but something tells me we can't use those either.


Thanks,

Kix

 

[N4KVE]

Kenwood TK-780 [VHF] or TK-880 [UHF] are great radios that I see for $40-$80. Programming cables are cheap, & CPS is free. Work in the ham, & commercial band. I use the 880, & it works as well as any similar Moto radio.

 

[kixntuff]

Honestly, if I was doing this?
Low band VHF. Or HF (2-30MHz), but getting a reliable HF radio set up on a motorcycle would be difficult.
California Highway Patrol uses Low Band VHF for most of their voice traffic. Works well over long distances, bends around hills well and can be pretty impressive on simplex. Trouble is a suitable antenna for low band VHF is going to be bigger than would probably be comfortable on a motorcycle. Off road it's going to be even worse. You'd probably be looking at a 4 foot long whip at minimum. That will take a beating off road. There are hand held low band VHF radios, but the antenna limitations make it tough. On a chase vehicle, adding a 1/4 wave whip antenna or a base loaded whip isn't much of a problem. They are usually a bit shorter than a CB antenna. A low band mobile radio is going to be heavy to carry on a motorcycle, so a portable/hand held radio is going to be the best option. Probably not a good solution for a cycle, better suited for a buggy or truck. Anyway, you'd really probably want to have the interoperability with Weatherman and others, so I'd stick with VHF.

Other than that a satellite phone is probably your best bet.

Hard to be a used Kenwood or Motorola mobile. I've got a few Motorola CDM model radios.
CDM-750 is a 4 channel radio. I've purchased them for as cheap as $75. VHF versions will cover 136-174MHz. I've got some running a combination of amateur radio 2 meter band an VHF commercial stuff. No LCD display.

CDM-1250 is a 64 or 128 channel. VHF models have same coverage as above. I've been purchasing these for $150-200. Nice LCD display.

CDM-1550 is a 160 channel. I've got one of these in my personal truck.

Programming is the costly part. Software is only legally available from Motorola.

Many of the Kenwood radios are a good choice. Often cheaper than Motorola's and the programming software is cheaper, too.
A TK-790 is a good VHF mobile. TK-7180 or NX-700 would be a good choice too.
TK-790 does 146-174 out of the box, but they can be stretched down to 144MHz. Available in 50 or 100 watt versions.
TK-7180 and NX-700 are cosmetically the same radio. 7180 is analog only. NX-700 is analog and NXDN/NexEdge digital. A bit newer than the 790, but a smaller radio.

Any one of those would be a good choice. On the used market it's kind of tricky to find a good one. Some risk involved buying used, but I've had good luck so far. All of them will cover the 2 meter amateur radio bands just fine, as well as legally working on the commercial stuff.

Key to getting the most out of your radio is to pay close attention to a really good antenna system. Buying a $200 radio and then ignoring the antenna would a bad idea. You don't have to spend a fortune on an antenna, but you should make sure you get a good name brand and have it properly installed and tuned. It'll really make a big difference in performance.

Don't even think about magnetic mount. If you are not willing to do a proper antenna installation, best back away now.

Thank you for the radio recommendations. I'm going to make a phone call and talk to a race communications sponsor and ask what specific frequencies we can operate on and still get weatherman to relay a message to us if needed. As for the motor cycle. We will be carrying a hand held Baofeng UV-82hp with a Nagoya 771 15.6" antenna in a back pack with no head set which I have already purchased. The radio will only come out during a break down and if sat phones fail the rider. We won't be as serious as some of the Trophy truck teams radioing ahead to their pit stops for exactly what needs to be done to the truck or for chit chatting with chase vehicles. The Mobile units will be monitoring weatherman and chosen simplex frequency at the same time. Mobile must be able to reach weatherman flying at 25,000 feet now or on top of mount Diablo,reach the rider if we pick him up on the simplex frequency and possibly reach the other chase vehicle while we are leap frogging the race course. I've done enough digging on antennas so far to know that I'm going to need to start another thread for that one. I have a few questions about antennas because they coming across as very important and complicated.

Kix

 

[mmckenna]

Sounds good, and sounds like a whole lot of fun.

 

[Project25_MASTR]

So I have some friends that run in the Texas circuit. The way the race coms coordinator had them set up was everyone licenses a handful of itinerant repeater pairs and a couple of simplex frequencies. Then at races requiring repeater coverage, they use itinerant repeaters (since everyone is licensed for the same itinerant pairs).

Now, I haven't gotten the info to this, but I believe they run CSQ repeaters and just have teams filter out what is not theirs by (D)PL.

 

[kixntuff]

So I have some friends that run in the Texas circuit. The way the race coms coordinator had them set up was everyone licenses a handful of itinerant repeater pairs and a couple of simplex frequencies. Then at races requiring repeater coverage, they use itinerant repeaters (since everyone is licensed for the same itinerant pairs).

Now, I haven't gotten the info to this, but I believe they run CSQ repeaters and just have teams filter out what is not theirs by (D)PL.

Man that would be awesome if Score-International could set up CSQ repeaters down the course, but they don't. To many would be needed and it would be very costly. Most of the money goes into safety and people to manage the race. This race is Massive and can go all the way down the Baja peninsula starting at the top in Ensenada and going all the way to the bottom in La Paz or Cabo San Lucas. They probably say it's just cheaper to have us rent Sat phones then flow the cost through the entry fee for repeaters. Who knows. By the sounds of things, we may have to use Pl tones just on all of the simplex frequencies. because there are so many radios in this race.

Kix

 

[Project25_MASTR]

Man that would be awesome if Score-International could set up CSQ repeaters down the course, but they don't. To many would be needed and it would be very costly. Most of the money goes into safety and people to manage the race. This race is Massive and can go all the way down the Baja peninsula starting at the top in Ensenada and going all the way to the bottom in La Paz or Cabo San Lucas. They probably say it's just cheaper to have us rent Sat phones then flow the cost through the entry fee for repeaters. Who knows. By the sounds of things, we may have to use Pl tones just on all of the simplex frequencies. because there are so many radios in this race.

Kix

I've been bouncing the idea around in my head of "upgrading" some friends to DMR based (added features such as integrated positioning) but Baja would require a massive Tier 3 system.