Radio Communication Methods During Emergencies- Part 2, by R. in NC

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Today, we’re continuing to look at communications devices in this communications overview section of the article. So far, we’ve look at Ham radio/licensed devices, but now we’re moving into non-FCC license dependence communication devices to consider.

Cell Phones – Using During An Emergency and Improving Reception

During an emergency it is very common that the local cell phone towers become saturated. Many people attempt to connect at the same time, resulting in busy signals. In addition, some cell towers have special equipment that restrict public use and dedicate additional bandwidth to emergency services. This section covers how to get a message out, as long as the cell tower is working.

SMS Texts

SMS texts (aka messages on an iPhone) use an alternate channel on cell phone towers called a control channel. This control channel is isolated from voice and data channels and is not impacted when too many voice and data connections are made. SMS also caches the message on your device and makes several attempts to deliver it, which is very useful if service is intermittent.

Because SMS is less impacted by cell tower saturation, it is more likely to send and receive messages. This is true even when you get a busy signal via voice, or standard data dependent applications like Facebook Messenger or Twitter will not work. It’s also important to note that because SMS uses a control channel on the cell phone tower, it is less impacted by bandwidth restrictions implemented by the government during an emergency.

In addition, when in an area with spotty cellphone reception, the packets sent via SMS have a higher level of reliability because SMS packets do not need to have a constant connection to the tower. Voice and data connections need to establish and maintain a connection to the tower in order to function. SMS connections are at send time only.

Cell Towers Operating in UHF Range

Cell phone and tower propagate or operate at frequency ranges from 700MHz to 1.9GHz, commonly referred to as UHF. What matters about cellphones operating in the UHF range is that UHF propagates using “line of sight”. LOS propagation means that the cellphone and the cell tower have to be within a range that is not impacted by the curve of the earth (about three miles). It also means that radio waves (UHF) can be bounced off some objects and can pass through others.

Take Advantage of UHF Propagation

You can take advantage of UHF propagation in the following ways:

  1. If you are far from your nearest tower, gain height. Try to make the call from the highest location you can.
  2. If you know the direction of your nearest tower, you can take advantage of hard objects, especially metal ones, by holding the cellphone very close to that object, with the cell between the tower and the hard object (brick/stone/metal wall of a building).
  3. You can create your own metal object by putting tinfoil on the back of the cell phone and pointing the cell phone screen at the tower. If you do not know where the tower is, you can add the tinfoil and rotate your cellphone until you have better reception.
  4. If you are adventurous, google “diy parabolic reflector cell phone”. This will show you many examples of using metal objects near the cell phone to increase your signal.

Useful Cell Phone Applications in Emergencies

There are a number of cell phone applications that are useful during an emergency. Below are some options:

  • 5-0 Radio Police Scanner – (free iPhone application) allows you to listen to emergency services, locally and nationwide.
  • Messages – (included iPhone application) SMS texting.
  • Viber – (free iPhone application) network-based calls and messaging.
  • Facebook Messenger free iPhone application) network-based text messages
  • Twitter (free iPhone application) network-based text messages
  • Echolink (free iPhone application; however, it requires a FCC Ham Radio License and call sign)
  • MyAPRS (free iPhone application; however, it requires a FCC Ham Radio License and call sign) network and RF (Radio) text messages, along with GPS locations of sender and receiver. The built-in map shows locations of 2m/70cm/1.25m repeaters).
  • PocketPacket (low cost APRS iPhone application; however, it requires a FCC Ham Radio License and call sign) with a cable to a HT (Portable 2M Ham radio). This can send text and position to other people running APRS. This can also be used to send texts via RF to Internet gateway servers, which can forward to remote cellphone SMS and Email. (More details covered in Ham Radio section.)

Marine Radio – (VHF)

These radios are similar in frequency to MURS. However, they are dedicated to operation in a marine environment.

Marine Radio has the following features/restrictions:

  • No license needed
  • VHF frequency range of 156 to 174 MHz with FM modulation
  • 1-25 watts output
  • Conditions over water extend radio waves
  • Almost always submersible; check your model
  • Monitored by the Coast Guard
  • No antenna restrictions
  • Illegal to operate outside of a maritime environment

MURS – (VHF) Multi-Use Radio Services

MURS radios are two-way, low power (2 watts), allows for removal of stock antenna and add-on of improved antennas. They operate in the VHF range (around 151MHz).

MURS has the following features/restrictions:

  • No license needed
  • Longer distance than FRS in suburban and rural areas due to waves bending around hills
  • Not as long range as CB in suburban and rural areas (CB allows between 4 and 12 watts.)
  • Less effective in urban/apartments areas, due to wavelength effect around concrete.
  • Products are not as available as FRS. Expect to shop online and have fewer choices.
  • 2 watts maximum output (PEP)
  • FM modulation
  • Five defined channels
  • Optional antennas can be used; however, they cannot be over 60 feet above ground.
  • Optional antennas can be about two feet long or more on the radio (better range with larger antennas).
  • Coax can be used to connect to permanent or larger antennas.
  • No repeaters allowed
  • FM Modulation
  • Has PL codes (Privacy codes), but these only restrict what you can hear, not what everyone else can hear.

FRS – (UHF) Family Radio Services

FRS radios are two way, low power (up to 2 watts on some channels), “walkie-talkies”. The antennas are fixed and cannot be extended legally. They operate in the UHF range (around 400MHz).

FRS has the following features/restrictions:

  • No license needed
  • Works better in urban environments than MURS and CB (higher frequency penetrates concrete better than lower frequencies, in general).
  • Less effective in suburban and rural areas. (Higher frequencies do not bend around hills as well as lower frequencies.)
  • Recent 2017 FCC changes have expanded the number of channels allowed to FRS; however, since these rules were just passed, your radio may not allow for the extended channels or the increase in wattage. (See http://wiki.radioreference.com/index.php/FRS/GMRS_combined_channel_chart for new frequency and wattage rules.)
  • FRS has something referred to as PL or “privacy channels”. These privacy channels restrict what you can hear and not who you can send to or hear you.
  • Output power is restricted by the FCC to 2 watts on some channels, and 0.5 watts on others. Anywhere between 0.5 to 2 watts is very low power for a portable two-way radio.
  • The UHF frequency range limits this to line of sight. Do not believe marketing when it comes to outrageous distances. You can communicate beyond about 3.5 miles, but you have to have both locations well above sea level. Even then the low wattage will cause issues when trying to hear the other person.
  • FRS equipment is restricted to a fixed antenna. You cannot legally swap out the installed antenna with one that is more efficient.
  • Shares some frequencies with GMRS
  • FM Modulation
  • No repeaters allowed
  • CERT uses FRS radios. CERT is an organization of volunteer local responders, often focused on search and rescue. Having the ability to operate on these frequencies may help guide assistance where it is most needed.
  • Low cost, commonly available at mega-stores

Recommendations and Comments on FRS

Although the wattage is low and there are antenna restrictions, having a few FRS radios has the specific advantage of communicating with CERT teams and with neighbors. The low cost of ownership also allows these radios to be excellent hand out radios for neighborhood communications in an emergency.

CB – Citizens Band Radio

CB radios are two way, low power HF radios that at one time were almost as popular as cell phones are today. They operate in the HF range (around 26MHz and 27MHz).

  • Note 1: Often, when shopping online for a good CB radio you will see comments about 10 meter band radios. The difference between 10 and (CB) 11 meters is small and often people illegally modify stronger Ham 10 meter radio to support 11 meter CB frequencies. These modifications are usually through hardware changes or firmware boot options.
  • Note 2: Several companies make special amplifiers for CB radios. They market these as 10 meter amplifiers with frequency ranges that overlap with CB frequencies. It is illegal to use these with CB’s, though many use them.

Features and Restrictions of CB Radio

CB has the following features/restrictions:

  • No license needed
  • Modulation restricted to AM and some have SSB
  • Better in suburban, rural than all other license-free options
  • No repeaters allowed
  • 4 watts on AM, 12 watts SSB (Single Side Band)
  • Antennas will be much longer than MURS or Marine CB.
  • Handheld CB’s do exist; however, antenna length makes handheld CB’s often impractical or hardly usable. If CB is your only distance choice, consider making a man-portable CB out of a car CB, battery (12v DC), antenna, and backpack instead of handheld.
  • Communications distance is slightly better than line of sight (maybe out to 10 miles), when conditions are very good.
  • When conditions are great, long distance communications are possible via sky wave propagation. Do not expect conditions to be great. Note that in 2017 the FCC lifted restrictions on sky wave communications over CB radios.
  • Non-SSB CB radios are very inexpensive ($30-$200 new). CB’s with SSB options are usually between $180 and $400 new.

Recommendations and Comments on CB Radios

  • Most truckers still have CB radios. During SHFT, having insight into the food transportation system may make the difference between getting extra supplies and waiting in a useless line. It will also help you to identify locations where people will be concentrated.
  • If you purchase a CB, make sure it has the SSB option. This adds two more levels of channels to talk on. Since all the power is focused into a single sideband, you also get greater power (12 watts) output and often greater range due to improved signal strength.
  • Most CB communications are vertically polarized. This means that “stick” type antennas are best, and the higher you get the antenna the better range you will have.
  • If you do not invest in a CB, you should at least have something like an HF radio that can listen to the CB frequencies.

See Also:

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17 Comments

  1. Just an excellent, excellent series of articles. Thank you. One note about iPhone messaging. With the more recent iPhones when you text someone on your screen you will see your sent message will appear either in a green or blue color bubble. If you are texting with another iPhone user the phone “knows” that and will send the message via the data network. For most communication the message will go back in forth with your fellow iPhone user in blue via the data network. If you are an iPhone user you’ve experienced the red alert symbol that a message didn’t go thru. It will ask “Send message via Text?”. If you touch yes it will send again via SMS and turn green.

    As the author noted in an emergency cell sites can become saturated and the voice and data network may not be available. But as he noted the SMS text path may be. If your message is important/time sensitive you can force the iPhone to send via SMS. Write and send your message as usual. The outgoing message to another iPhone will by default show in a blue bubble. Touch and hold that blue bubble. A pop up menu will appear the the option “Send as Text Message” and the message will send as SMS and turn green. The person who you are sending to may get the message twice, once via data netork and once by SMS. Better twice than delayed or not at all.

    One other tip. You can write and save pre-written “canned” text messages on your iPhone. Open the “Notes” app. Write your canned message and save. When you need to send the message open the note. Look in the corner (latest OS upper right corner) and you will see an icon of a square with an arrow at the top. Touch that and a menu appears with the option to send as message. Touch and your canned message appears in the message app.

  2. Sorry for double posting, but had two other ideas/tips.

    The author notes how you can “take advantage of UHF propagation”. My addition to his list would be to do your best to minimize obstacles, and stop moving. If you are inside a building and having difficulty with a voice call, step outside. You no longer have steel, brick and wood antenuating (making weaker) your cell phone signal. If you are in a car, remember you are in a 3/4 steel faraday cage. Step out of your car. Little things can make a difference.

    Also, we’ve all been driving and talking on the phone and the call breaks up and then either gets better or is dropped. When you started your call you were close to cell tower but as you drove you got farther away. The computers in the cell site track your position and direction then “hands you off” to the next cell tower/site in your direction of travel. Good cell coverage and the hand off is totally seamless. But, if you are on the edge of tower coverage, and the next tower is too far away the call gets dropped. If you are in the middle of an emergency call and it’s breaking up the next tower might pick you up, but might not. So, stop the car and get out (if safe). Or, backtrack to where you had the strong signal conversation.

    The author has an excellent list of apps for your smart phone. I might add a couple others. All local TV and radio stations are constantly promoting “Stay in touch, download our app”. Might be a good idea. When the power and cable is out and you forgot your battery powered AM/FM radio you are in an information black out. If the cell data network is still up you can get vital local info from these local TV/AM/FM smart phone apps. Some even stream local news live now. If you live in an area with more than one news source, download and try each station app. Some are good, some are really bad. Find the good one and have it in your information tool kit.

  3. Thank you for the article. In the section on marine radios it states that it is illlegal to use outside a “maritime environment”. Seems broadly defined. Does this mean ocean? Great lakes? “Navigable Waterways” (as defined by the government, i think the corps of engineers), anywhere a sea breeze is part of the local weather pattern? I ask the question outside of an emergency situation. Thanks in advance.

  4. As an “Extra” class ham operator, I am really enjoying this excellent and well written article. It is inevitable that with a topic of this magnitude, there will be some errors. For example, in this statement, “Almost all CB communications are horizontally polarized. This means that “stick” type antennas are best, and the higher you get the antenna the better range you will have.”, the author is correct that “stick” types antennas are best but it is because most CB communications are VERTICALLY polarized, not horizontal. Be well. LD

  5. For what it is worth, in the hors after the big earthquake in Mexico City a few weeks ago, cell and SMS service was completely dead only data-based services like WhatsApp worked. (popular outside the US)

    It was many hours before normal cellular service was available.

  6. Thanks for all the feedback folks.

    Midwest Marco
    I didn’t know about the icon color code in Messages, that’s great info. Also, thanks for pointing out the picket-fencing and tower handoff effects of cell reception. With a subject like this it’s hard to know when to stop without writing hundreds of pages.

    Kaffr
    “maritime environment” is vague, but that’s how the FCC states it. The general rule of thumb is: part of that conversation is on a floating boat. The type of water that boat is on, such as a river, lake or ocean, won’t matter. I also double you would have an issue if that boat was in dry dock as long as you were using the radio from that point. Now, if the boat is sitting in your driveway 30 miles from the nearest water? That would probably be an issue with the FCC.

    LD
    Great catch. I must have proofread this a hundred times and still missed that one. Thanks JWR for fixing my typo, that kind of mistake would make things confusing for folks, especially as we start to move into the HAM radio section.

  7. Some relevant information on a new first-responder network that is was recently bid out. AT&T* has been selected by the First Responder Network Authority (FirstNet) to build and manage the first broadband network dedicated to America’s police, firefighters and emergency medical services (EMS). The FirstNet network will cover all 50 states, 5 U.S. territories and the District of Columbia, including rural communities and tribal lands in those states and territories.

    To help FirstNet achieve its public safety mission, AT&T has assembled a team that includes Motorola Solutions, General Dynamics, Sapient Consulting and Inmarsat Government.

    The broad terms of this 25-year agreement between FirstNet and AT&T are:
    FirstNet will provide 20 MHz of high-value, telecommunications spectrum and success-based payments of $6.5 billion over the next five years to support the network build out;
    FirstNet’s funding was raised from previous FCC spectrum auctions.

  8. I have little confidence in cell phones. My wife has a smart phone with AT&T service. We can go to the Grand Canyon and to a hot spot where we have five bars and the phone shows no 4GL and you cannot call, text or check messages. Meanwhile there are 20 other people around you calling, texting and using the internet on their phones. AT&T can’t explain it. Also I was walking down the Bright Angel Trail about a mile or so down and a guy is walking past talking away on his cell phone like he was next door to them. So I turned on my phone and had zero bars. WTF! This is during good times; full service; everything working fine!

  9. DC
    I’ve heard a lot of talk about FirstNet but didn’t think they got that far. For those interested more info can be found at https://firstnet.gov/

    FirstNet is similar in concept to D-Star. It has channels for Data and Voice, and can function through repeaters and point to point. The intent is to provide smartphone like features to first responders – being able to send pictures, texts, etc.

    From what I can tell, it will be layered with current LRM (Digital Radio Voice) and LTE (Cell Phone Network) systems giving PTT capabilities to first responders smart devices.

    With all this technology being dependent on consistent connection states (like a cell data network – LTE), I seriously wonder how it will work out under major event conditions where the impacted area extends beyond line of sight or takes out cell towers.

    There are a few postings on their website referencing frequencies being sought in the 10 meter and 30 meter ranges but I don’t think those have gotten FCC approval yet. If I were to bet, these frequencies would be for backup communications between different (police, ems, fire, FEMA, hospital?) stations.

    All in all, probably very useful unless things get very bad over a larger area, like an area impacted by a hurricane. The sarcastic side of me says “works great until you really, really need it.”

  10. Wow thanks for all the discussion so far. I’m a new General class and know that my knowledge is low. One tip we keep mentioning to people is to focus on the fact that those teensy weensy little antennas on handheld devices really don’t push out the full power of your radio battery but a ‘mathematically longer’ antenna will. Further, when you push on your transmitter button, visualization of your radio wave going out is like a donut slid over the top of your little antenna. The beam is puffy on the sides of the antenna, right?

    But what about the tip of the antenna area? It’s in the hole. There’s little to no donut, nor radio signal, in the tip area of the antenna. It’s a donut hole.

    Fighting fires in Wyoming in the Big Horn Mountains we had aircraft to call in but greenhorns would look at the plane coming in, or the help hovering overhead, and tip their handheld antenna so it points directly at the aircraft.

    So they put the donut hole of their radio beam right onto the aircraft and then got frustrated at lack of comms. “Reach out and touch no one”.

    A common saying in our ham club is “A vertical antenna transmits in all directions equally poorly”.

    So remember those two points when using your handhelds. Poor antenna transmission capability, and donut holes.

    If you attend some clubs meetings you can learn things like how to double your antenna capability with 18 inches of scavenged speaker wire, and much, much more.

    God Bless, and keep the discussion going.

  12. Wheatley Fisher,

    Thanks for the feedback and examples. I cover different types of antennas later in the article, so I’ll help explain what you are talking to a larger audience and save some for later in the article.

    The donut/bubble: aka a radiation pattern of an antenna. For a visual representation try searching in Google images for “radiation pattern of a vertical antenna” will show many examples of how the radio wave is “pushed off” of the antenna. The radiation patters are graphed out over an outer circle, and that outer circle is based on a theoretically perfect antenna (dipole hung at an optimal high).

    Vertical Antennas: actually there are many types of vertical antennas, and each can have a unique radiation pattern, so it’s difficult to answer your question/comment on which way it radiates but the general rule is that Vertical Antennas are vertically polarized. They push the signal out broadside from the antenna in all directions, and the null (area of minimal signal strength) is typically directly above the antenna.. typically.

    As for the poor reception/transmitting of a vertical antenna.. for the most part you are talking about the infamous “rubber duck” as a vertical. In this antenna design, you become the RF ground by holding it (note this is an RF ground aka RF counterpoise – not to be confused with an electrical ground. [Please note I am trying to keep a complex subject simple here. This can get kind of “Pepsi vs. Coke” on some boards]).

    We/You do not make for a good RF ground/counterpoise. By attaching a 19.5″ wire to the 2 meter HT (hand held radio) at a point usually near where your hand naturally wraps around the radio or at the base where the antenna attaches, you can greatly increase the signal. That’s because the RF signal “pushes off of the counterpoise wire” and since it is a length ratio of the RF wave it is more effective than pushing off of you. By directing where that wire points, you can actually make it directional (focusing signal to a specific location). More details on this can be found here: http://hamuniverse.com/htantennamod.html

    Most station or base verticals have counterpoises attached to the ground section of the coax attachment. This greatly improves performance of the vertical antenna. Many have different lengths to allow for the verticals support of multiple bands. Usually each counterpoise wire is 1/4 wavelength but height of the vertical has an impact and these lengths are usually tuned to your specific deployment. (antenna tuners covered later in the article).

    On a side note: the volunteer firefighters in my area have absolutely horrible antennas on their hand held VHF radios. Unfortunately they almost have to be bad antennas. Running through a burning building with a 19″ whip antenna catching on everything is unsafe. They could use higher frequencies instead, but it’s a tradeoff between what works inside an apartment building or mini-mall, and what works out to the neighbors farm.

  14. A cb new out of the box should be”tuned and peaked” for maximum performance as the factory tune is often poor. A quality cb shop does this quite inexpensively,a “hot final” can increase your range several miles(10-15 miles is easy with antenna below 13’6″). A good(noise cancelling)mike is a good upgrade.

    1. Good point, thanks VT!

      Those shops used to be everywhere back in the CB hay day. Today you might have to do some driving to find one, depending on where you live. If you have a good reference please add it so others can see an example of what to expect for work and cost.

      As for antennas, FireStick has some antennas are common for CBs and that have screws at the end for tuning to the channel you are on he most (http://www.firestik.com).

  15. One thought…under the rewrite of Part 95 regarding GMRS, during times of emergency unlicensed users may run under a licensed users license. Of course, to me, during an emergency, I’ll toss the rule book out…so people need to know how to do basic communications, regardless of spectrum used. When the emergency condition is over, the FCC can come and get me…

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