Faraday

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CH1

We’ll start with local communications. Failure of land lines and cell phone relays could isolate you from family members and friends you would want on your side in an emergency. After a hurricane a few miles might as well be a few thousand. Something might also happen while you are away from home, if only shopping on the other side of town. I hope you have a bug-out bag in your car to help you get home…

Before diving into the subject, I need to lay out some bases on frequencies and communication modes. It isn’t hard to understand and I will do my best to make it as simple as possible. Take your local radio station for instance.. Let’s say you listen to 102.5 FM. 102.5 is the frequency, in this case 102.5 megahertz, which is 102,500,000 cycles per second. Frequencies are measured in Hertz, meaning cycles per second. Imagine flipping the light switch in your kitchen.. At 102.5MHz you would be flipping it more than a hundred million times per second. Pretty easy concept. As far as units go, we use the Hertz, Kilohertz (x1000 Hertz), Megahertz (x1,000,000 Hertz) and Gigahertz (1,000,000,000 Hertz). You are already familiar with “Gigahertz” if you ever had to shop for a computer…

FM is the modulation mode, which means the way your voice (or data) is coded before sending it by radio waves. I won’t get into details here but just know that there are different modes. You probably listen to AM radio sometimes, which is a different voice mode from FM. AM (amplitude modulation) was invented before FM (frequency modulation) and is of course still in use today by short-wave radio stations because it is more efficient than FM. AM will go further than FM using the same power but doesn’t sound as clear. This is why radio stations prefer FM for music. For local communications you will be using AM or FM, but on different frequencies than your local radio stations.

So, why use different frequencies and which ones are useful to you? For practical matters, we will divide frequencies in two parts: HF or High Frequency, and VHF/UHF or Very High Frequency and Ultra High Frequency. HF, as far as Ham radio is concerned goes from about 1600KHz to 30MHz. UHF goes up to a few Gigahertz. So, your local FM radio station uses VHF which is above 30MHz but below about 400MHz, and your AM station uses HF, around 1MHz. What’s the difference? You see, the problem with radio is that the earth is round but radio waves travel in straight lines… So how do you contact someone who is beyond line-of-sight? If it wasn’t for the ionosphere, we would never have been able to do so before the invention of the communications satellite. There would have been no Titanic survivors! Fortunately radio waves bounce on the ionosphere! Under certain circumstances… They can even bounce on the earth and go all around the world! The ionosphere will bounce radio waves up to around 50MHz, and not very often at that frequency. It depends on solar activity. That’s why you’ll never hear an FM radio station from Japan! But you might hear an AM one on HF if you have a big enough antenna.

For local communications everyone uses VHF and UHF, except for CB radios which use HF on 27MHz. We can use HF for local communications as well as VHF/UHF but we run into another problem, antenna size… The length of any antenna depends on the frequency. You can’t use any antenna size… It is inversely proportional to the frequency used. Antennas are usually half a wavelength. Take 7MHz for instance, which is a popular Ham HF frequency.. The size of a half-wave antenna is around 66ft. A bit long for a handheld radio! Another common Ham band for local communications is the 2 meter band around 146MHz. A half-wave antenna for that frequency is about 3.2ft. Now we can slap that on a walkie-talkie.. You will learn about all that simple math while studying for your Ham Technician license.

Let’s look at the no-license-required options for local comms: You probably already own a pair of FRS handheld radios. You can find them at Walmart for as low as $30. How good are they? Pretty good it turns out, but their range is limited. The manufacturers pretend up to twenty or thirty miles, but that would be floating in space talking to someone on the ground. The earth being round, again, we run into the line-of-sight-problem. Two humans standing up with a radio at head-height will only be able to talk to about six miles… That goes for any radio at that height, FRS or not. Because of their low power and small antennas, actual range is more like two miles maximum. A good way to extend range would be to climb on your roof, but obstructions will reduce the practical range and you’ll never get more than a few miles. FRS (family radio service) radios are more useful to keep in touch while moving as a group in case some members get separated.

An alternative to FRS handhelds are MURS radios. They aren’t much different but since less people know about them you get a little more privacy… Anyone can listen to FRS. Few people use MURS because they cost a bit more. Range is similar to FRS in that they are limited by the same laws of physics.

Personally I don’t have much money to spend on gear so I opted for FRS. If things turn ugly I can give a few to my friends and establish a simple code for operational security. I highly suggest that you do buy as many as you need for each members of you inner circle, plus a couple spares.

Then we have the good old CB radios. They operate in AM on 27MHz. Furthermore, you get forty channels. Since this is HF, it is occasionally possible to communicate over vast distances using a CB (citizen band) radio, although the FCC doesn’t allow you to talk to anyone beyond 250 miles. I don’t think they enforce it… There are very few CB handhelds as most models are for car or home use. Antennas are fairly long, not very practical for something you might want top carry in your pocket. It is however a popular band to listen to, though if you have kids I’d suggest keeping them away from it! CB used to be civil and polite, self policing. Not any more… If you decide to buy a CB I suggest you get one with SSB modes, which we will talk about in our upcoming long distance communications article. See my post about the Galaxy DX-979. Getting a CB means that you will have to learn a bit about antenna tuning and how to measure SWR (standing wave ratio), which is how much power is not radiated by the antenna and could fry your radio turning it into a receiver only.. It is simple but can’t be ignored. Your antenna must be of a precise specific length to transmit with. So, if you buy a CB radio, also buy a SWR meter. More about that in our HF article later.

Ham radio is you best choice for emergency communications. Not only the radios are of better quality and more versatile but you also gain a whole community of knowledgeable individuals ready to help you. The Technician exam is so easy it’s almost laughable. It will only set you back about $15 and your license will be valid for ten years. The FCC assigns you a call sign and that’s the extent of it. You gain access to many frequencies and modes for worldwide communications. The Technician license is mostly for local communications but allows some long-range contacts on some bands.

The most common local Ham band is 2m FM, which covers from 144 to 148MHz. What’s so great about it compared to say, FRS, since again the laws of physics come into play? In one word, repeaters! Ham operators install repeaters on high towers all over the country. You can be pretty sure there is one within range of your house. These repeaters relay your signal over large distances, sometimes up to one or two hundred miles. Not bad for using a small handheld radio. Repeaters might not operate for long after a large scale emergency but at least they will keep you connected until the generators run out of gas.

Another popular band like 2m is the 70cm band from 420 to 450MHz. Most handheld radios offer both band in one device which is what I suggest you get. Prices range from $35 to $600 but you can get a great radio for $150. Ignore expensive digital models because they don’t work any better than the good old FM ones. More private maybe, but that’s about it.

One of my favorite model is the Yaesu FT-270. It is a 2m only model, very rugged and waterproof. You can actually dunk the darn thing in a bucket of water while it’s on and it will keep working! Best thing is, price is around $120. Another cheap option is the Chinese Baofeng UV-5R and UV-5R+ models. They have both 2m and 70cm and can be programmed to include FRS and MURS channels, though you can legally only listen. In an emergency however, you can use any radio on any frequency, so a good option to have. The UV-5R has a big flaw however and that is the external microphone jack. It breaks after you use it a few times, limiting you to use the radio with an external microphone only. I have two and both are broken. One I received already broken and the other one broke within a couple weeks. I now use them with external microphones.. Still a good deal for $50 a pop. If you get one I suggest never plugging in an external microphone and using it as-is. That way it will last a very long time. It’s too bad a great radio like this was built with sub-standard jacks.

UV-5R+ and Yaesu FT-270R

UV-5R+ and Yaesu FT-270R

Get your Ham radio license! Go to the ARRL site to find an exam session and buy a book. Then open a free account on QRZ.com. They have free practice exams online. If you are local to Sarasota, contact me and I will answer any question you might have. If you are hesitating because you fear being put on some list, let me tell you that you are already on a few and a Ham radio license won’t make any difference. There are no good reasons in my opinion not to get one. I would even suggest trying to pass both the Technician and General exams on the same session. It isn’t much harder and will give you access to a flurry of frequencies on HF.

So far we have our few FRS or MURS handhelds, maybe a CB for the house or car, and a couple 2m/70cm Ham HTs (handi-talkies). What else do we need? We need to know what’s going on beyond our town, even beyond our continent! Everyone needs a short-wave receiver. Short-wave is HF. Something like the Tecsun PL-380 for bout $45. Whatever you buy make sure it has a plug for an external antenna. The built-in antennas are way too small to be of any use. You will plug in a long wire, say 60ft. or more to get distant stations. Also make sure the receiver decodes SSB to listen to Ham radio operators. Usually a good short-wave receiver covers all HF Ham bands and everything else in between. Some Ham radio transceivers (transmitter/receiver) allow you to listen in between Ham bands, thus act as a short-wave receiver. If you plan on getting into Ham radio you might just buy one, even before you get your license, if only to listen. Otherwise, do buy a short-wave receiver!

There you have it, all you need for local communications and getting news from distant stations. How are we going to power it all up without electricity? First, make sure all the devices you buy can be powered with AA batteries.. They are everywhere and rechargeable ones can be recharged with a solar panel like the GoalZero Nomad 7, which I use. You can charge four batteries at a time in about four hours. Make sure you buy AA battery adapters for your HTs and have the correct connectors and battery packs for your other devices.

GoalZero Nomad7

GoalZero Nomad7

RM40 with battery pack

RM40 with battery pack

You need to protect your gear against strong magnetic fields generated by lightning or an EMP. I use a cookie tin can with my radios wrapped in plastic as to not touch the sides of the can.. It isn’t grounded but I hope it would work. I tried placing my cell phone inside then calling it, it didn’t ring. I also soldered a piece of wire between the can and the lid to insure a good electrical contact. I sometimes leave a radio outside the box but never leave it plugged-in while not in use.

Questions and comment are welcome. I will be glad to help anyone get into Ham radio. The next article will cover global communications. Stay tuned!

I decided to build an Elecraft K1. What the hell is that You might ask.. Though you probably guessed it is a radio. I’m on a roll. I know, I know, I just finished building a small one (DC20B) and am waiting for another tiny transceiver called a Rock-Mite. You need to learn to walk before you can run.. Why not buy something already made? It isn’t more expensive.. Well, the Elecraft K1 has an excellent reputation, and it isn’t sold assembled. If you want a new one, you must build it. I am good at that stuff, and do enjoy the process. Still, I could find a working Ham radio on Ebay for the same price; but that would be a used item. Not to mention that the K1 is the cutest little radio (did I just say that?).

There is one peculiar thing about this radio, aside from all it’s qualities, that is, you can’t talk in it.. Morse code only! Also known as “CW” (continuous wave). So I am learning Morse code, and it is far from easy. Why bother? First, a Morse-only transceiver is much simpler and smaller than an SSB (voice) one. It draws less current, which becomes very important when operating on batteries. The K1 will happily work for days on eight AA batteries! For example, a Yaesu FT-817ND draws 450mA on receive. The K1 draws 55mA! More importantly, when propagation conditions are bad, a CW signal will punch through the ether when another mode won’t. In an emergency, being heard might be a life-or-death condition. Even with no cell phone coverage and no satellites overhead, there is a good chance the K1 will be heard somewhere, even thousands of miles away. Yes, thousands of miles directly, on eight AA batteries! What else can do that? It doesn’t mean I won’t take my cell phone or a Spot when hiking far from civilization. However, cell phone coverage is spotty in the North West, and with the Spot, you can’t specify the type of emergency, and can only use it for dire situations. If I need anti-venom after a snake bite, it won’t do me any good to get picked-up by a helicopter if they don’t have the serum with them.. A radio allows you to call for a specific kind of help. Like any other gear, if it is too heavy or too big, you will most likely not take it with you. Light and small is better when you need to carry it on your back.

My plans are to first complete the 20/40m model with no add-ons. Then, I will build the built-in antenna tuner. This option allows you to use a random wire as an antenna without risking frying the transmitter. If you lost your antenna and all you can find is a length of barb wire, the tuner can save your bacon. Just hang it up a tree, press the tuner button, and seconds later, if you’re lucky, you will be having a conversation. I might add a noise blanker later.. One item I decided against is the built-in battery pack. You can’t charge the batteries while they are inside the case, so what’s the point? I heard it is a flimsy add-on anyway. I don’t think I’ll need more than two bands, but time will tell. The antenna I chose is the Par EF-10/20/40 MkII end-fed dipole. Also on my wish list is a solar panel (PowerFilm AA Battery Solar Panel Charger) to charge those AA rechargeable batteries. For EMP protection, I decided to get some TechProtect Faraday bags.

I will document the build and post it. Average build time is about thirty hours, but I am pretty fast with a soldering iron. I will start next week-end (June 9th), stay tuned for the article, and maybe a video. Hopefully by then I will have learned a few more letters of Morse!

Since I am on a radio kick (funny how old hobbies resurface..), I decided to dig my old CB radio from storage. I bought it around 1989-90, and hadn’t turned it on since. I was worried it would go up in smoke when I turned it on, but to my surprise, it worked. I hooked up a 3ft. balcony antenna to it and heard… Nothing but static. Maybe it had not aged so well after all. In radio, the antenna is everything. My little three footer wasn’t going to provide stellar performance. Unless I could get it high enough. I ended-up on my deck, swinging a wrench attached to a nylon string, aiming for a promising branch above the roof. Five minutes later, I was listening to stations from Mexico, Costa Rica, and New Mexico. That was of course using Single Side Band (LSB or USB). There is nothing left for me on the regular AM band. At least on SSB, you hear much less obscenities, and conversations are more “professional.” A CB with SSB modes thus is a good choice for emergency communications (yes, I changed my mind..).

Anyone around Sarasota wanting to chat on SSB, post in the comments below!

As far as radios go, I would suggest that you stay away from “export” models, which have more channels and power than legally allowed. Not only could you get in trouble with the FCC, but you could also create interferences on other legitimate stations or electronic devices nearby. You don’t need more than the legal 12 watts SSB to reach stations thousands of miles away. Forty channels isn’t much, that is true, but I would rather operate legally with these limitations than face a fine I probably can’t afford.

We are now at the peak of solar activity, which creates ideal propagation conditions. We will probably get decent propagation for the next couple years. The solar cycle lasts eleven years. It was at it’s peak in 1980 when I bought my first CB, and again in 1990 when I bought my second one. It is peaking again right now, isn’t that convenient! You can still make long distance contacts during low activity, but it doesn’t happen as often…

Here are the current conditions (look at 11m for CB):



 
My choice of “newest” radio is the Galaxy DX 979.
Galaxy DX 979

Galaxy DX 979


It is a legal radio, CB of course, so you can use it without any license. I’d like to replace my “shorty” antenna by a Solarcon Imax 2000 (24 feet long), but that will have to wait. Like I said, the antenna is everything. For situations like camping or temporary base operation, I would get a “Double Bazooka” wire antenna. For a car, the K-40 is a proven design, and you don’t have to drill a hole in your roof! Don’t forget to get an SWR meter to tune your antenna (if your radio doesn’t have one built-in) or you could fry your transmitter.

A good channel to listen to is 38 LSB, here is a video of an operator making contact from PA to NC:



 
My old transceiver will be mothballed in a Faraday cage, waiting for an EMP Doomsday that may never come. If it did happen, information would be worth it’s weight in gold !? ;-). A good battery and a 12v solar panel would provide power. With all electromagnetic interferences gone, the radio frequencies would be very quiet, but for the few prepared individuals still on the air with working transmitters.