Ham (Amateur) Radio
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When most people think of ham radio they think of Morse code and long distance phone(voice) communications across continents and around the world. The Amateur radio service, which is licensed and controlled by the FCC in America, is for emergency communications, monitoring and policing of the unused radio frequencies, and for general fun and experimentation with radio technologies. It boils down to allowing anyone with an Amateur license to use the frequencies which have not been set aside for commercial, military, police, fire, ambulance, broadcasting etc. These are quite a few different bands (a band is a range of frequencies). And remember that ANYONE (even without a license) in an emergency situation may call for help and otherwise relay information about the situation using a ham radio. But no fooling around as pranks are not taken lightly. I have heard that the long time standard of SOS has been changed. If a reader knows anything about this please leave a comment. “Mayday” would be the long standing voice or phone distress signal.
Frequencies can be broken down as LF(Low Frequency), MF(Medium Frequency), HF(High Frequency), VHF (Very High Frequency), UHF(Ultra High Frequency), SHF(Super High Frequency or microwave). Ham bands begin in the MF range at 160 meter wave length. Frequencies are in Hertz, Kilohertz, Megahertz, Gigahertz. The longer the wave length of course the lower the frequency. As an example the VHF 2 meter band is tuned between 144.000 MHz and 148.000 MHz. The wave length of each frequency within in this varies but is near 2 meters in length. Since you don’t usually vary the length of the antenna, antenna tuners help to match the output frequency to the length of the antenna in use. This is where we get into SWR and Power, topics that I won’t cover in this article. The jest of it is that if the antenna is not perfectly matched to the wave length, then some of the power is reflected back to the radio. This can be as bad as not transmitting well or at all or as bad as in killing the radio.
Antenna’s are best made as tall as the wave is long. But often this is not feasible so that the antenna must be made 1/2 wave length, 1/4, 1/5th or some other fraction. A 160 meter band would need a 525 foot tall vertical antenna if fully sized. You can see how this would not fall in to the average individual’s budget. However at 1/8th wave length a 20 meter (95ft)vertical antenna might be doable. It would also function as a full wave antenna for the 20 meter band. Radio waves propagate from the antenna, meaning they “go outward”, in a circular, spherical or elliptical pattern. There are many kinds and styles of antennas. Whole books are written on the topic of antenna design. There has been complex software made for analyzing radio wave patterns for various antenna designs. Common antenna types would be random length wire, vertical, Di-pole and Yagi (Yagi is like the old TV roof antennas).
Different wave lengths have different properties in the manner in which they will propagate, bounce around or skip. The famous world wide ham bands are the MF and mainly the HF bands. There are no LF bands for hams to use. VHF, UHF and SHF are simply too short to bounce around the globe. They fly on out into space instead. The longer of the VHF is the 6 meter wave length which will rarely but occasionally bounce for long distances. This bounce is known as skip. Each band within the HF range has its own properties and characteristics for this skip. Bands are known to be open if skipping or closed if not. What causes this skip? Depends on the band, but time of day or night, season of year and sunspot activity are the main factors. More sunspots are better. The sun operates on an 11 year cycle for low to high sunspot activity. In 2010 it was at the 11 year low. Its just now begun a cycle back towards the high side.
What this means is that though ham radio can be world wide, and global, no line of communications is ever guaranteed to be available between two points on the globe if they are too far apart. Too far means within a few hundred miles apart or more or less sometimes. All types of radio waves have ground wave propagation. This means with 50 to 100 watts of power they can go from 10 miles to 100 miles or possible a bit further over hill and over dale. All forms work consistently line of sight for a distance of 5 to 20 miles or so.
Again the world famous ham radio bands that ham radio is known for would be 160m, 80m, 40m, 30m, 20m, 17m, 12m, 10m, 6m in wave lengths. On a side note, CB (citizen band) is 11m wave length. This means that like 10m its closest ham band, it will skip if the conditions are right usually in summer months only. However CB is regulated so that the user may only legally transmit with 5 watts of power. And at that power level it won’t go far. I’m a trucker and I can testify that CB usually won’t go farther than line of sight, which is sometimes only across the parking lot. Ham operators may transmit using up to 1500 watts of power. But usually only 50 to 100 is sufficient.
Morse code is still used widely but is no longer required to get the ham license. Morse code is still of use. When no other signal can get through Morse code can. It is simple and easy to interpret even over static. It uses lower power and less bandwidth than voice. If you want light weight and low power and long distance under extreme conditions then you want to use Morse code. Here is a link to a web site teaching Morse code. Morse Code Training You can find free software on the web that will help you learn and practice Morse code.
Ham radio is not famous for the VHF and UHF bands. Yet these are very useful and popular bands. They rarely skip, but are widely used for ground wave propagation and line of sight propagation. These bands sometimes propagate via thermal ducting. This is where they travel between warm and cold air layers in the atmosphere. Hams have found ways to make use of these VHF and UHF bands via repeater towers. Using a repeater hams can reach distances of around 200 miles and more if repeaters are linked. If repeaters are linked then any distance can be achieved as long as transmitting party and receiving party are within 100 miles or so of any of the repeaters in the chain.
Popular VHF and UHF bands are 6 meter, 2 meter, 70 cm. There is a set of 70cm repeaters linked in tornado alley area (Oklahoma, Kansas, Texas, Nebraska, Arkansas, Missouri, Louisiana) of the USA.They cover 50,000 square miles and are used during extreme weather by storm spotters. This is called the Sky Warn system. Spotters are hams or other official spotters who have been trained in spotting tornadoes.
ARRL (American Radio Relay League) publishes a Repeater Directory for the USA. This guide list 1000’s of towers, hundreds in each state for each band. To tune to one you simply input the frequency and an access tone frequency if it is required. If you key the mic within range of the repeater it will beep, talk to you and/or give you its call sign in Morse code. There are groups of people who meet each week for what is called a net meeting on given repeaters. A net meeting occurs on a given repeater for one hour or so at a given time of day on a given day of the week. This is for emergency messaging practice. For mobile use I have bought the ARRL software Travel Plus Repeater Directory which displays a map of the USA and shows repeater locations, frequencies, access tones and other info. This software is very worth while to have if mobile. Though I couldn’t get it to work with my GPS setup, I was able to set up a radius of say 30 miles. I then pan around and click the map at my location to get a list of all repeaters within a given radius. This worked quit fast and I could do this while driving.
If you really get into ham radio you can even do things like use ham satellites (called oscars which are orbital repeaters), talk to the international space station on 2 meter band, or even bounce VHF or SHF off the moon.
What is required to get a ham license? You must get a book Ham Radio License Manual from ARRL to study. It comes with practice test questions. It covers mostly rules and regulations, radio theory, antenna theory and setup, basic electronics, electrical safety, call signs,wave propagation, transmitting modes, EMF radiation safety and more. I studied this book for about 6 months in my spare time and then got the first license. This license is the Technician license. It is a single 35 question multiple choice test. It only has two questions on basic electronics so you could miss those two and still pass it. You can take it at Ham Fest. Ham Fest are a swap meet for hams. It cost $14 to take. This license gives you access to the VHF and UHF and SHF frequencies but not the long distance HF and MF frequencies. To gain access to the global transmission privileges you need to study another slightly thicker book General Class License Manual and take another 35 question multiple choice test. This gets you the General Class licenses. I studied for one year in my spare time for this one.
There is a whole lot more to ham radio than this though. Digital age has brought digital radios and repeaters. It has also allowed VOIP, or Voice over Internet Protocol. Now you can tune into a digital repeater which sends the message over the internet to another digital repeater somewhere in the world. I doubt I am doing a decent job of covering everything that can be done with ham radio.
In disaster situations, such as earthquake and weather related catastrophe, when government and commercial communications are down, hams are operating. They operate on emergency and mobile power. A good book for this is “Solar Living Source Book”. I always recommend this to hams as it covers off grid power so well. Ham serve another purpose which is to police the air waves. A ham operator must identify with a valid call sign every 10 minutes. This means that anyone operating without one or in any illegal manner will be turned in fast by legal hams. The FCC is very strict about this and huge fines and jail are not out of the question here. They can triangulate on anyone using radio illegally very fast. Hams will help them. This means ham radio is a great form of radio for family and fun. Its good for the religious folks that don’t want to put up with a lot of cursing and foul language too. Its polite and nice. Unlike CB near any truck stop.
My call sign is KE5OAG. When I want to raise someone on the radio I say, “This is KE5OAG monitoring”, “This is KE5OAG Mobile monitoring” or in the 18 wheeler “This is KE5OAG Diesel Mobile monitoring”. One day on a trip from New Orleans Louisiana, to Birmingham Alabama, I contacted 15 repeaters and talked to 10 hams. One of the hams was another trucker. Also note that if you have a “Handy Talkie”, the ham version of a walky talky, and you are within 5 miles of a repeater, you may talk to other hams up to 100 miles away. Radio’s are not usually built from scratch anymore. Radio’s can have about any price tag you can imagine. Used radio’s can be found for pennies on the dime of what the new ones cost. Used radio’s are usually in great shape because hams take pride in their equipment. Hams have swap meets called Ham Fest where they sell or trade everything you can think of that might be related to ham radio. There are also ham clubs. I suspect many repeaters are funded and maintained by ham clubs.
For Truckers and possibly other mobile operators.
First let me say that in trucking when you are a company driver you are in the same position as other careers where company vehicles are provided. This means that the company dictates what you can or can’t do with that truck or vehicle in regards to alterations, especially to the electrical system. In general you can only transmit on 5 to 10 watts on the electrical system as it is, from the cigarette lighter or any other 12 volt connections. To be able to transmit on higher power you must install a heavier power cable from the radio to the battery terminals. Most companies will not allow you to attach the cables to their system at all. They always state that it is a warranty issue. They just assume any electrical modifications would endanger their equipment and deny any suggestions you might have. In rare cases they might agree to install the power cables for you. Other problems you might run into is how to run the cables into the cab. They don’t want holes drilled in their precious body parts or frame or floor or whatever, no matter how small.
I once tried to have a lawn mower battery in the floor of my truck which I recharged from the cigarette lighter. I could get some full power transmission this way for 10 to 15 minutes. Then back to 5 watts only. It worked but was not a great solution. One reason trucking companies resist letting drivers power off of their batteries is that it puts extra demand on their alternators which burns them out faster and in the end cost them more money. It also burns out batteries faster. Its one of those deals.
About the only good solutions I see for company drivers is to use alligator clips. Make sure they are heavy duty and not thin cheap ones. I’m not sure if alligator clips have watt or amp ratings, but if they do make sure they are good enough to do the job. Use proper fusing between the alligator clips and the radio and of course use the proper gauge wire for the wattage you intend to put out. In most mobile cases we are talking 50 watts as most ham radios come out of the box to transmit on 50 watt at high power without further linear amplifications. Some may be more such as 100 watts out of the box. As you may know hams may transmit at up to 1500 watts per the license. Though I hear rumor that some truck electronics might be affected adversely by such a high output. I do know that if you try to transmit off the cigarette lighter with more than 5 watts you will destroy circuits, blows fuses and burn out lights in the cab. Don’t ask me how I know this. Yes strange things will happen. Worse yet you may cause a situation that might lead to fire. So heed my advice here.
A bad thing for truckers and radio antennas is that modern trucks are coming with crazy mirror mount brackets that are very wide or thick and look to be unusable for mounting antennas. Though many trucks still come with the older style chrome mirror mounts which are superb for mounting antennas. I do not have much advice for the antennas themselves except to say that I don’t see why vertical ham sticks wouldn’t work for all bands. I used a 5/8’s wave stainless steel whip for 2 meter, worked great. For the travel plus software I recommend getting a “Netbook” pc because of its small size and its lower power requirements. I have heard rumor that it is illegal to have any screen within view of the drivers seat in a commercial vehicle that is larger in size that 5″x5″. This means most laptops/notebooks are illegal. A Netbook of that size however would be legal. Still if you wreck a truck while operating a netbook and they could prove it and there was a fatality, you would be in deep dodo (i.e. prison time). If extremely careful and conscious a trucker may be able to glance at the screen of the netbook and adjust the radio carefully. Windows may come with voice command control now, which would be safer than trying to operate a keyboard and mouse to pan the view on the national map, or find and click your current location. GPS operating properly would be safest, because the travel plus software would update the list of repeaters as you drive. From what I could tell it seemed that the Travel Plus software was designed to work with hand held GPS devices. But I’m not sure that it wouldn’t work with other GPS software or devices. I just know that it wouldn’t work with Delorme Earthmate GPS.
On a last note we have the problem of running the antenna coax cables from the radio to the antennas outside the truck. Again you can’t put holes in the truck. I have run them through the window having it a bit cracked but I often felt that I might be breaking that single wire in the coax with bending. I met another trucker on the road who showed me his setup and he had simply run the coax through the door jam and closed the door on it. The door jam has rubber seals that gently press on the coax and there is enough room between the door frame and body for the coax to make it without being mashed or bent. For the truck you need and want watt meters(forward and reflect power), SWR meters, antenna analyzer and antenna tuner. If you don’t get all of this you will be guessing about your setup too much. Sure you can make the radio work but when it doesn’t work well you will be guessing and wondering, that is without those tools.
|Ham Radio LIcense Manual|
|General Class License Manual|