The Magic of Radio Part 2: Nuts and Bolts of Radio


George Ure and Gaye Levy, Contributors
Activist Post

With SOPA and Internet controls possibly on the near horizon, having the ability to both listen and communicate freely may become the exclusive domain of private radio operators.

With that in mind, last week we began our series on the “Magic of Radio” with a discussion of some basic shortwave radio equipment, including general shortwave listening gear and weather radios.  This week we present part two of our two-part series.

Gaye aka G2:  This week we want to move on to the next level of the hobby, so how about starting with an explanation of antennas.

George aka G1: Sure! Easy to understand and it only takes a few paragraphs to get the basics. When it comes to antennas, there is generally only one number you need to remember – 468.  Here’s why that number is important:

If you know what frequency your radio is tuned to, you can use the formula 468 divided by the frequency (f) in MHz to come out with a value telling you how long a ½ wavelength antenna should be.

Say you really wanted to put up a good ham radio antenna for the 7-MHz band. How long would it be? The answer is (468/7=) 66.857 feet. But, since we don’t happen to have a tape measure handy calibrated in 1-10th or 1-100th of a foot increments, we save the 66 feet and add 12 inches times .857 to convert that ugly decimal into 10.28 inches – and since .28 of an inch is close to a quarter inch in decimal form, we would round it off as 66’ 10 ¼ “ and call it good for overall length.

But there’s one more thing to do.  We have to cut this in half so we have two pieces of wire, one connected to either end of a center insulator. So two wires of 33’ 5 1/8th” would be good. As a matter of practice, we might add 4 to 6 inches at the end so we can wrap around the insulators which go at the ends and at the middle. Our feed line – oftentimes coaxial cable – would attach at the center with the middle conductor going to one side of the antenna, while the outer shield and braid going to the other.

For listening, you don’t need to be so precise. In fact, a 33-foot piece of wire makes a dandy antenna by itself, and even better if the radio is connected to a good ground, such as a ground rod or copper cold water pipe. Now you’re talking first-class shortwave reception.

Remember our formula? The antenna lengths for the AM broadcasting band gets to be a lot longer. A radio station on the AM band, on 710 KHz, for example, would have a ½ wavelength of (468/.77 =) 659 feet!  So the optimal length for a wire receiving antenna on the AM band is about 330 feet and a good ground.

It’s about here that practical physics strikes both the broadcaster and the home listener when it comes to antennas.

On the broadcasting side, a dipole isn’t generally used on the AM band. Instead, if you take half of the half-wave antenna and mount it vertically (as a tower) you can “fool” the antenna into thinking the ground is the other half of the antenna.  Still, this is a very useful fact to know: You can make an educated “guess” as to an AM radio station’s operating frequency by simply looking at an antenna and inferring the operating frequency:

Radio Service
1/2 Wave
1/4 Wave
 Vertical Feet
1/4 Wave
AM station on 710 KHz (0.71 MHz)          659.15          329.58  — 
Am Station on 1100 KHz (1.1 MHz)          425.45          212.73  — 
AM Station on 1510 KHz (1.5 MHz)          309.93          154.97  — 
Texas Traffic Net SSB 3.873 MHz          120.84            60.42  — 
5.8 MHz shortwave band            80.69            40.34  — 
Low Power Ham Code 7.040 MHz            66.48            33.24  — 
Maritime SSB Ham Net 14.3 MHz            32.73            16.36  — 
27 MHz CB Radio            17.33              8.67          104.00
120 MHz Aircraft Voice Radio              3.90              1.95            23.40
145 MHz 2 Meter Ham Band              3.23              1.61            19.37
162.5 MHz NOAA Weather              2.88              1.44            17.28
468 MHZ Public Services              1.00              0.50              6.00
800 MHZ Trunking Radios              0.59             0.29              3.51
2.4 GHz Routers              0.20 0.10 1.17

G2:  Wait a minute! How come my AM radio doesn’t have a 330-foot wire on it?

G1:  There are special cases and one of them is the AM radio band.  Since – as you probably know – the antenna should be so long.  Is there a way to shorten it? You bet! Wind a bunch of antenna wire (thin stuff) around a special hunk of powdered iron or magnetically suitable material called “ferrite”. Interesting stuff, this ferrite and you can read the Wikipedia entry on ferrite core products here.

The ferrite core wound antenna provides a compromise: The size is smaller, but so is the performance. Although I do have to say there are some dandy radio antennas for AM distance listening (called “DX’ing) which are pretty interesting. One of these is the CC Radio Twin Coil Ferrite antenna which runs about $100 from Amazon while the other is the Kaito AN-200 Tunable Passive AM Antenna which runs about $25.

6698234829 092d32d13d m The Magic of Radio Part 2: Nutz and Bolts of Radio
G2:  Are there packages that have everything included in them?

G1:  No, not generally. The reason is a lot of people like to “roll their own” package after reading reviews of shortwave gear.

But you can get some good guidance by looking at what people are pairing the external AM antennas with. For example, one combination seems to be the Twin Coil antenna along with a CC Radio 2 which covers the AM band, FM, weather frequencies, and the two-meter ham band. Great for local listening.

On the other hand, for about $100 less, you can get a Tecsun PL660 radio which has shortwave with all of the shortwave bands.  It includes single sideband, Morse code capability and has aircraft too.  On the other hand, you don’t get the weather band and the two-meter band.  In case you didn’t notice, it’s hard to find an all things to all people set-up.

But for a shortwave basic set-up, the Kaito AN200 antenna, the Tecsun radio and the Sangean wind-up shortwave wire antenna can get you going for about $155 (not counting shipping).

G2: So what do some of these different signals sound like on shortwave and what’s that about?

G1: The earliest radios – back in Tesla and Marconi times – were continuous wave radios. What we would think of as “carriers” getting turned on and off – that’s the essential of Morse code. You can get a sense of what stations communicating in Morse sounds like from this YouTube video though the bells at the beginning are not code.  And you can hear some of the different modes on the Tecsun from a Lithuanian location here.

Although AM is the mode of choice for some shortwave broadcasters, there are other mode of operation. Single sideband voice, for example, gets rid of the wasted power of one sideband of an AM signal and tosses out the carrier too, so you get nothing but talk power.

By the way, if you want to see what a ham radio contest sounds like with good equipment and a first-class operator driving the gear, take a look at the SSB contest run rate in this video and realize that that virtually everyone of those contacts being logged by K5TR is a different state, plus a handful of foreign countries.

The application of computers to frequency control and multi-frequency modem technology is called automatic link establishment which you can hear on a military radio starting 13 seconds into this video.

A much more practical marriage between computers and HF ham radio is something called BPSK -31. It’s really cool because it allows you to have a keyboard chat – without using the internet. A demo video here on YouTube is really good and you can hear what the signals sound like in background.

G2:  But George, what is the point?  I am getting lost.

G1: Well, at the low end of things, you can get yourself into a position where you have at least input as to what’s going on in the world that’s independent (to some degree) of governmental or corporate filtering.

At the next level up it is a technically challenging hobby which provides important backup (and sometimes primary) communication during emergencies in places like Joplin, and so forth.  Using a ham radio satellite, for example, here is a video of a guy standing with a handheld radio in one hand and an antenna in the other talking to a distant state and talking to Mexico, as well.

And, at the highest level, with the hobbies combined, shortwave, ham radio, and electronic & computer hobbyists have helped push the envelope of how we can communicate with one another.

And it’s this “urge to communicate in new and novel” ways that I find most interesting, because outside of equipment costs, it is possible to personally communicate worldwide with very little filtering by “establishment” or paradigm-defenders in between people of one country and another.

I think there’s great value to this, because even though we presently seem likely to see the Intellectual Property and Stop Online Piracy Act come down on shared information if it’s from an IP-defending source, humans still have an underlying urge to communicate and get to know one another regardless of political divisions, most of which are highly artificial constructs, anyway.

The more ways we are able to communicate amongst ourselves, the more we will evolve as humans and learn to share and celebrate our common desires. So, yeah, I think this communications stuff – far beyond the routers and Internet-based systems – is an important backup as well as being a frontier all of its own.

G2: OK, where to from here?

G1: Lately, my studies have been along lines that support an evolution into capitalism 2.0 – a world where most efficient means are used, rather than the most controlled or most profitable means. I know that sounds like academic gobbledygook, but two words sum it up: More Change.

The changes to come are not necessarily going to come politely knocking on the front door. Nor, are they all likely to be encompassed by non-profit domestic media. And once the SOPA regulations are enacted later this year and China-style Internet controls are in place, there will be a great stifled voice of the people.

Even on AM and FM radio in most major cities, if you drive around, you can still occasionally find “pirate radio” stations serving a neighborhood or local interest ground. If – as some have postulated – there is a generalized decline in government money available for “enforcement” of various laws and “regulations” we could well see a whole next-generation of “pirate radio” springing up, depending on how hard SOPA is implemented.

There’s evidence from lots of countries, revolutions, rebellions, and change states, that radio is one of those tools which is hard to turn off, hard to control, especially when coupled with a computer.

I assume you know that on eBay there are 20-watt AM transmitters to be had for less than $700 including shipping? This means a person with a USB microphone, a laptop, and power can set up and move an AM transmitter around an urban area. I’m not promoting it, but when the general population and the governing powers of many countries have gotten out of “synch” far enough, pirate radio is something that can – and has – happened. I even saw a 300-watt transmitter set up for 105.9 FM stereo for $1,250.

Just seems to me that getting used to tuning around will be a way to “keep your ears on,” because it might give you some very important clues about the kind of future that will arrive about the same time.

G2:  What next?

G1:  After you’ve gotten a sense of what’s out there – the next stop would be the national ham radio organization American Radio Relay League. Their site has tools to help you find a local “Elmer” – a kind of radio buddy – who can coach you a bit on the ins and outs of the hobby.

Oh, and listening to fire and police calls on a Friday night, especially when it happens to be when welfare checks hit and a full moon, is endlessly interesting, too.  Scanners like the Uniden BC340CRS 100-Channel Clock Radio Scanner – which is $80 at Amazon make another good way to get the drop on current events, too.

G2:  And if someone wants to come at this from the police and fire scanner side?

G1:  Then a basic scanner would be good, but then transition into a ‘grown up’ ham radio like the Yaesu 857D or the Icom 7000 – both of which have many followers. Either radio will get you on the VHF ham bands and in addition have killer shortwave and HF ham radio transmitting and receiving capability. The only downside is the price.  By the time you get radio and a 25-am 12-volt power supply for it, you’re pushing $1,200 by the time you and your “Elmer” get an antenna put up for the HF bands, but that’s the high-class route.  It just costs a lot of money.

The last two hints would be to visit and read the equipment reviews and visit manufacturer web sites. The reviews may seem harsh but there are some manufacturers which may lean a little toward snake oil on some of their antenna claims.  You just need to read some.

And so to summarize . . .

Even if you never plan to get your basic ham radio license, there is a whole world of information available to you from the perspective of other people and other countries.  This information is available for free (other than the cost of equipment) day and night via shortwave radio.

To that end – the free, uncensored flow of information – we hope this has been a useful discussion of the nuts and bolts of shortwave radio.  One last thing:  keep in mind that any radio that you plan to acquire as part of your “prepping” should run on 12-volt power.  Otherwise, should main power fail, you’ll have a very high-tech paperweight.

The Magic of Radio Part 1: Why Shortwave Radio Matters

Hang on and enjoy the ride…

Introducing Strategic-Living: a practical and useful online magazine providing inspiration and guidance as we make our way through the maze of changes that are coming our way. In collaboration with my friend and colleague, George Ure, Strategic-Living will offer a synthesis of Urban Survival and Backdoor Survival with much more detailed tips, tools and strategies for creating a vibrant and sustainable lifestyle wherever your path may take you. Think of Urban Survival and Backdoor Survival as your roadmap and Strategic-Living as your detailed guidebook. Here you will find articles and photos, diagrams and how-to’s, and a healthy dose get-out-there and do it with kick-in-the-ass inspiration.

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