E-Mail 'Radio Communication Methods During Emergencies- Part 1, by R. in NC' To A Friend

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1. I’m lookin forward to this series, as comm is often overlooked in preps. In my group, we standardized with Cobra CB 29X’s, but the point of these is to work towards establishing initial linkup during the first stages of an event. We all love within 15 miles of one another, so communicating with each other works, but it’s hardly secure.

2. The writer has established an excellent foundation for this series of articles. Note his discussion on “common usage technologies” CB radio and the use of “non licensed devices”.

   The key is to communicate, which includes the ability to listen (monitoring) when transmitting may be ill advised.
   As usual, I am very much looking forward to this series of articles.

3. 1) Re the Dead zone, the military found in Vietnam that wet jungle vegetation could cut the groundwave transmission to just a few miles , giving a big gap out to the 300 mile line where skywaves bounced back to earth.

   2) So they used a teepee-like NVIS antenna to send the transmission straight up to bounce off the ionosphere and back down, thereby giving good reception in the dead zone out to about 70 miles. Works mainly with 2-8 Mhz, depending on time of day and conditions.
   See https://en.wikipedia.org/wiki/Near_vertical_incidence_skywave

   3) For vehicles, a NVIS-like effect can be reportedly be acquired by bending a tall vertical antenna over to the horizontal –e.g, with a cord connecting to the opposite bumper.

   https://www.toyota-gib.com/eng/accessories/communications/hf-radio/codan-nvis-antenna-kit-nvis.html

   1. Don,

      Thanks for the Vietnam example. Later in the article, I will cover NVIS to some degree, along with the impact that terrain, sun cycles, and time of year has on RF communications. This is why testing and practice are so important.

      Not to get too far ahead of myself, but using NVIS requires both sites to have an NVIS setup. I have a neighbor about 30 miles away, and I have an NVIS config on 80 meters. He can hear me fine, I can receive him at a level just over background static. Why? Because he doesn’t have an NVIS setup. Test, test, and retest.

      Lee, I will talk about the need for large frequency coverage across multiple bands, and getting equipment that covers critical frequencies, as the article progresses, but excellent point.

      Jason, consider yourself very lucky to get 15 miles on a CB especially on a rig without SSB. You must have great terrain working in your favor, or have an amp, (for emergency use only of course). I’ll talk more about CB hardware and options soon, along with comparisons with other frequencies.

      Encryption, and frequency hopping technologies exist, but keep in mind that they are legally “fuzzy” when it comes to the FCC. I will make a reference to it when discussing packets and email transmissions over HAM bands.

      Thanks for the feedback everyone, and for those just reading, feel free to ask questions.

4. Thanks for kicking this off , Robert. I keep urging my groups to get trained and get licensed. I understand the reluctance to add another government data point onto our lives but getting licensed entails both training and entrance into an enormous asset network. That network includes both human and material resources but the net result really is about individual skill development to implement each of them.

   I get weary of folks who keep saying things to the effect of, “start operating when SHTF” both sans license and sans training/experience. That’s the same logic about getting any skill….seriously flawed logic.

   I’m grateful some of my groups have members who are now licensed and engaged. Be proactive. Become radio operators for the formal emergency networks. Take control. Become community influences. Shape the norm.

   Best wishes and God Bless,

   1. Thanks Wheatley, I hear that a lot too. I’m even guilty of it. I pushed off getting licensed for a long time, using confiscation issues, FCC, and anonymity as an excuse when in reality I just didn’t want to take a test.

      I saw those questions about electronics and most went right over my head, until I applied myself and started learning. I had zero background in electronics, ohms law, and couldn’t tell you what a capacitor was.

      I didn’t realize that the test was setup in a way where you can just memorize the answers. Of course, learning is best but for those without an electronics background it’s a easy way to start.

      Heck, if I can get a general class license, they anyone can.
      That’s why later in the article I have a whole section on getting a license and why it is so important to be able to actually use the equipment and not just buy something on amazon and put it away “for emergency use.”

      If I have one goal here, it’s to encourage people to get their license and to start using and learning their radios. 73

5. In addition to security issues, does there exist any ability to prevent radio frequency ‘jamming’ by et al unfriendly forces?

   1. The term “Jamming” is more of a movie thing. Some evil government agency flips a switch and then you can’t communicate. In reality, you can still transmit and receive.

      The issue known as “Jamming” is the result of their signal being so strong that you can’t hear anything else. Kind of like when one person whispers in your right ear while someone is yelling in your left ear. Keep in mind that the person you are talking to might not even hear the “Jammer”

      This happens all the time on a frequency without any kind of intent behind it. People use the same frequencies but they can’t hear you so they continue like you aren’t there. You can hear them, and the person you are trying to talk to, but they start stepping all over the one you want to chat with because their signal is much stronger.

      Even natural electrical phenomenons or a bad light bulb, socket or just poorly insulated AC wires can have the same impact.

      There are two basic solutions around this. If the problem-ed source bandwidth is narrow enough you can use noise blanking and filters to block out your receiving of their signal. The second is even simpler.. change the frequency to something you have previously agreed on.

6. i am a licensed ham operator with a general license and most of all operators will not talk to an unlicensed operator except under dire emergencies! just saying!!

7. I took the first test. Personally, I regret mumbling my way through log and scientific notation in high school. We have a 10 meter net on Mondays. Took me four weeks to finally connect and register as a check-in. Antenna orientations and power sources all have to be in line. Pretty sure NVIS does not work at 2, 6 and 10. My Elmer set me straight on that one. Fine people in Ham clubs with whom you want to be associated.

   1. RV
      You are correct, NVIS does not work for 2 meters and 6 meters (both being VHF with 6 meters having some HF properties). For 10 meters it would depend on many propagation factors so I would put that in the “almost always no” category.

      Both the 2 and 6 meter bands, along with 10 have additional propagation methods that are sporadic, along with EME (bouncing signals between the earth and moon) for 2 Meters all the way through Microwave bands (not 10m). We will cover those to a greater extent as the article progresses.

8. Thanks Robert for this important and nicely presented information. Folks should know there’s a bit more to all this than just picking up a radio and pressing TALK. Good work and very much looking forward to the rest of your installments! 73

9. preppers seem to have this notion that they’ll buy some equipment and stash it in a metal trash can for “someday” when there’s no FCC, and then they’ll be able to communicate. I hate to break it to you, but ham radio is called a “hobby” because there’s a lot to it. If communication is important to your plans, I suggest you get your ham license and start using this stuff NOW, so that you’ll know how when (if) the time comes during your lifetime. And if the end doesn’t come in time for you? Bummer, you only had a hobby. Although you will need to provide your address to a government that already has it, you can specify a PO box for public info.

10. I am a 62 year old lady with little background in electronics. I just got my general ham license. I had to study hard, but it was worth the effort. It can be done folks; don’t let the test scare you. I found studying with flash cards available for free on the internet to be most helpful.

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