January 29, 2022

Radios for Emergency and SHTF Use – Part 4, by Rufus King

(Continued from Part 3. This concludes the article.)

A friend of mine suggested that I include some discussion of less costly MURS radios for those prepping on a modest budget. There are not nearly as many options for MURS radios as there are for GMRS. A bit of research reveals that a Hong Kong-based firm called Retevis offers Chinese-made radios that it markets for MURS use. Their model RT21V is available in a two-pack for $44.99. They are CTCSS capable, but they do not come with any tones already set up. The Retevis units have the five MURS channels ordered in the sequence they appear in the FCC regulations: channel 1 is 151.820, channel 2 is 151.880, channel 3 is 151.940, channel 4 is 154.570, and channel 5 is 154.600 MHz. Here is a chart comparing the channels on the two units:

Frequency Retevis Channel Motorola Channel Allowable Bandwidth
151.820 1 3 11.25KHz
151.880 2 4 11.25KHz
151.940 3 5 11.25KHz
154.570 4 1 20.0 KHz
154.600 5 2 20.0 KHz

I ordered a pair of Retevis RT21V radios and evaluated them for this article. My first impression was that you get what you pay for. The cases, batteries, antennas, and chargers all looked okay, but as soon as I started turning the knobs, they felt loose with a lot of slop in them. I charged the batteries for the two units and started testing them. The two would talk to each other with no problems. Where I ran into limitations was when I tried to get them to interoperate with my Motorola RMM-2050’s.

I mentioned above that the RMM-2050 comes from the factory set up to use a sub-audible tone of 67.0Hz for both send and receive. In contrast, the RT21V’s are not set up to transmit tones by default, so out of the box, I could hear the RMM-2050 on the RT21V but not the other way around. My goal was to configure the RT21Vs to work seamlessly with the RMM-2050’s, so they could serve as a less costly alternative. I was only partially successful.

I downloaded the free software from the Retevis website and connected a $10 programming cable purchased online. I was able to use this setup to program the RT21V’s, although there are very limited options as to what you can program, the principal setting being the CTCSS codes. I set the Retevis units to both send a 67.0Hz tone and to require the same tone in order to break squelch and play an incoming transmission. I then tried them again with the Motorolas. What I found was that they worked fine on 151.820, 151.880, and 151.940. On the other two channels, 154.570 and 154.600, I could not hear the Retevis radios on the Motorolas even with the correct tone programmed in. If you check the Allowable Bandwidth column on the chart above, you will notice that the two channels that do not work allow a bandwidth of 20.0KHz, whereas the other three only allow 11.25KHz.

In brief, bandwidth is the amount of frequency range that is used to transmit a signal. The nominal frequency is the center of the transmission, but the actual radio signal occupies a range of frequencies both above and below the nominal frequency. FRS, GMRS, and MURS radios all use FM, which means the frequency of the signal is varied in order to add information to the radio signal. When you key the microphone and speak, the frequency of the signal you are transmitting goes up and down as you talk. Radios can be designed to use more or less bandwidth to encode a signal. Narrower channel bandwidth will allow more users to simultaneously use the same range of radio spectrum in the same geographic area at the same time. Wider bandwidth may sound better depending on the circuitry, and the signals may carry further. I suspect this is why Motorola reordered the channels to put the two wideband channels first on the RMM-2050.

The manual for the Retevis radios indicates that they use the 20.0KHz bandwidth as allowed on 154.570 and 154.600, but the programming software shows all five channels using only 11.25KHz, and the setting cannot be changed using the software. I am fairly certain that the Motorola radios are actually using the wider bandwidth on these two channels, and that the reason the Motorolas can’t hear the Retevis units on the wide band frequencies has something to do with the bandwidth discrepancy.

The net result of my test is that if you are willing to program them, the Retevis RT21V’s can be made to interoperate with the Motorola RMM-2050’s, but only on three of the five available MURS channels. If you are going to buy only Retevis units and use them to talk only to each other, then this is not an issue for you. The build quality of the Retevis units is clearly not as robust, but they are also much less expensive. Like anything else in life, you get what you pay for, and the Retevis units may or may not hold up to serious use.

Amateur Radio (Ham Radio)

I frequently see questions posted online where people ask what kind of “ham radio” they should get for an emergency. The answer for most people is that you should not get one at all. If you have read this far, you now know that there are several other options available for emergency personal communications where all you have to do is turn the radio on, choose from a selection of pre-programmed channels, press the transmit key, and talk. With the exception of GMRS, you do not even need a license.

Amateur radio is a completely different animal. It is a technical hobby designed for experimentation and personal communication. You must have a license in order to legally transmit on amateur frequencies. 47 CFR 97.5. In order to get the license, you must take and pass a licensing exam. There are three exams, one for each of the three levels of license. The Technician and General tests are not terribly difficult. The Amateur Extra test is more of a challenge. The rationale for this is that amateurs are allowed to use a very broad range of equipment. Unlike with CB, FRS, GMRS, or MURS, your transmitter does not have to be certified by the FCC. You can build your own, and as long as it conforms to certain technical requirements, does not transmit out of band, and does not emit too much power or interfere with other communications, you are good to go. Few amateurs build their own transmitters in these days of (relatively) inexpensive solid state radios, but there is vast array of equipment on the market aimed at amateurs that would not be legal for any other use. In light of this, the FCC wants you to know the rules and some basic technical information.

With one minor exception (on 60 meters) amateur frequencies are not channelized. There are ranges of spectrum you are allowed to use based on your license class, and you are free to transmit within them using various modes of voice and digital communication. Some segments are reserved for data transmission specifically. You can build your own antennas (and many do), and in most circumstances you are allowed to run up to 1500 watts of power. 47 CFR 97.313. You are required to identify your transmissions with your FCC-assigned call sign. 47 CFR 97.119.

But the key to all of these privileges is you have to learn. You do not just pull a radio designed for amateur use out of the box and start talking. Even VHF and UHF handhelds need to be programmed, and that takes some knowledge and skill. It is not terribly difficult, but it requires more effort than most people, and even most preppers, are willing to exert.

If you get at least a General Class license, you have the privilege of operating on the HF bands as described above. This can allow you to talk to people literally all over the world, but there is a steep learning curve. When I had my newly minted General license and fired up my first HF radio, I was quickly sobered by how difficult it was to operate effectively. So, I practiced and learned. But if you are not willing to put in many hours of effort to learn the equipment and operating procedures, do not waste your money on an HF station. A basic setup is in the neighborhood of $2000, and it is not money well spent if you do not learn how to use it. After the grid goes down is not the time to learn.

A caveat to that is that an HF transceiver does make a really excellent (if expensive) shortwave receiver. Even without a license, you can listen to shortwave broadcast channels, and you can also listen in on ham traffic without transmitting. That can be very valuable, but you still need to know how to use the radio, and you need to rig up a suitable antenna and power supply that will work when the grid is down. And that takes knowledge and skill.

I have read many Internet posts by people who insist that they have no intention of asking for government permission and they will just operate on amateur frequencies illegally when SHTF. It is certainly plausible that in a wide-scale breakdown of the rule of law and the social order, the FCC will no longer be operating and there will be no one to stop you. The problem is that you will not have the skills to operate effectively. You will not know which modes to use on which bands, what time of day different bands are most effective, the meaning of the various shorthand codes ham operators use, or any number of other things you need to know to communicate effectively. The only way to learn such skills is to get a license, perhaps join an amateur radio club, and practice.

If you are not willing to do that, then save your money. Buy some FRS, GMRS, or MURS handheld radios and a shortwave receiver or two and be content. Amateur radio is not for everyone.

Recommendations for Preppers

So now for the TL;DR or “too long, didn’t read” part of the article. There is no magic radio solution that will replace the functionality of a cell phone when the infrastructure that supports cell phones is no longer available. Short-range communications among your family or group is readily achievable. Longer-range communications are achievable if someone in the group is willing to get licensed and learn to use amateur HF equipment. Ideally, someone in your group can become the radio expert, get licensed, and become proficient at programming and maintaining radios.

My thinking is to equip each group member with a Motorola RMM-2050 MURS unit and have a few spares. Remember that your communications are in-the-clear and act accordingly. There is nothing to stop you from using some codes on MURS (it is illegal on the amateur bands to transmit “messages encoded for the purpose of obscuring their meaning” 47 CFR 97.113). If that is more than you can or want to spend, FRS radios may serve your purpose, but most of them are too limited in build quality and durability for my taste. The Retevis MURS units may also be an option with the limitations discussed above.

If you do have someone with radio knowledge in your family or group, it is likely quite useful to have a field portable station set up with an HF rig, laptop, VHF/UHF rig, backup power, suitable antennas, and coax feedlines. In an emergency the VHF/UHF radio can talk to FRS, GMRS, or MURS radios, and it can always listen for transmissions on those frequencies.

Like every other aspect of prepping you have to identify the gaps in your capabilities, prioritize, and use the resources available to you. – R.F. King

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