Archive for the ‘About Ham Radio’ Category
Ham Radios are actually pretty simplistic in their operation. They depend on radio waves to get their message out.
Radio Frequencies
Hams use a variety of radio frequencies to communicate. Non-hams can hear what is being transmitted via their own receivers or scanners, but cannot participate in the action without a transmitter or a license. The ham operator can only use certain radio frequencies to transmit from these frequencies are allocated by the FCC for amateur use. Hams may operate from just above the AM broadcast band to the microwave region, in the gigahertz range. Most of the Ham Bands are found in the frequency range that goes from above the AM radio band (1.6 MHz) to just above the citizens band (27 MHz). Certain bands are dedicated during certain times of the day. The day time hours find 15 to 27 MHz is used for long distance transmission. During the night time hours 1.6 to 15 MHz is used for long distance transmission.
The bands are called “short wave” bands which are unlike frequencies used by FM radio stations and TV stations. FM radio and TV stations use what is known as line of sight bands, these bands only travel 40 or 50 miles. Short waves use the airwaves to bounce the signal off the ionosphere from the transmitter to the receiver’s antenna. The higher the frequency is, the “shorter” the wavelength is.
Generally hams get their beginning on VHF FM, using small hand-held transceivers which transmit on one frequency than receives on a different one.
They use FM repeaters that have been put in place by local radio clubs. The repeaters typically use space that is owned by local Television stations. These repeaters are set up on large antennas that the TV station uses to transmit its signal. The repeaters uses transmit and receive pairs to relay information back and forth. Frequency pairs are set up by Ham Radio groups and are kept at a long enough distance from each other not to cause interference.
There is new cutting edge technology that is coming more and more into use. Instead of using these repeaters to catch a signal and send out communications, some hams are able to use satellites.
Equipment
Historically Ham Radios depended on a series of tubes and electrodes to send out and receive a signal, some amateur radio aficionados still use this system but the majority have moved into the digital age and largely no longer use radio tubes to transmit and receive.
There can be a couple of different ways that Ham Radio is able to transmit. The oldest form of Ham Radio that is still widely in use today is to have two separate parts, a receiver and a transmitter. The receiver pulls in the signal from other hams and the transmitter sends the signal out. There are also transceiver’s these send and accept signals in one unit. This type of equipment is usually found as hand held’s and mobile units.
Most serious Ham’s prefer the two separate units with a separate antenna, to reach longer distances. Antennas of course play a huge roll is Ham operations. The most used 146-MHz (2-meter) antenna is a 19-inch quarter-wave whip. It has a wavelength of 146 MHz approximately 2 (300 divided by 146) meters, and a quarter wave of 2 meters is about 19 inches (50 cm). Hams have devised some unusual antennas and revel in finding one that works.
How to Communicate
In some cases the ham will speak into either a stationary microphone that sits on a surface and looks much like the type of device that singers use, some choose the handheld microphone that has the buttons on the side to send their voice out over the airwaves.
In some cases the ham operator will use Morse code to communicate, while it is not necessary to know Morse code when using a ham radio it is beneficial to know it. Morse code can often be detected when the radio waves are not strong enough to carry the complex inflexion of voice but can efficiently carry the beep tones of Morse code.
Ham Radio operation is a very basic form of communication, although simplistic in its design it takes years to master.
“Hello!” Was the very first word every broadcast over the radio. Few folks that are not entrenched in Ham Operation know the history of the radio.
Who Is Reginald Fessenden?
Reginald Fessenden invented the radio! Canadian Reginald Fessenden adopted his love of transmission when he was a mere lad. After Alexander Graham Bell invented the telephone young Reginald has been quoted as saying to a family member “Why do they have to have wires?” This was the first step in a life long journey to answer that very question.
Like all great inventions, the earliest attempts were miserable failed attempts. His theories earned him a government contract, Fessenden, and his assistant Thiessen, worked diligently to meet the challenge until they were able to meet with success.
Fruit and The Radio
Fessenden founded the National Electric Signaling Company (NESCO) with money invested by two wealthy fruit company owners once he had fulfilled his contractual obligations to the government, because of his failed attempts the government opted not to renew funding. As part of the United Fruit Company he worked to figure out a way for their ships at sea could communicate with the folks back in Pittsburgh.
The money that his backers invested bought high powered transmitters and antenna systems. In June of 1906 the first ever voice transmission was sent and received successfully a total of 12 miles away. Fessenden continued to plug away at improvements until he reached the point where he knew his invention was a success.
Merry Christmas
Six months after the first ever voice transmission over the air waves a surprise transmission to ships on the day before Christmas in nineteen six.
As his wife and employees as co-conspirator’s he prepared a special Christmas program On ship operators were told to tune in to receive a special Christmas message on December 24th at 9:00 pm . Radio operators sat stunned when 9:00 pm rolled around and a voice came over the air calling out “CQ, CQ”.
This was the first “radio” program. Ships across the North Atlantic were treated to Handel’s “Largo” played on a Victrola and “O, Holy Night” played for “the audience” by Fessenden on his violin.
The Rest Is History
This new technology called Radio set the world on fire. Hobbyist and early day techies could not get enough of this device and loved the idea of talking to people may miles away without being tied to a cord. They were, and are still, called “amateur” radio operators. Long before commercial broadcasting was on the radar “amateur” radio operators filled the airwaves.
Official laws were first instituted in 1912 by congress. A newly formed agency was put in place by the federal government in nineteen twenty seven that was responsible for regulating radio usage including ham radio operations.
Amateur radio operators have been on the cutting edge of communication since the inception of the radio. They were the first to use cell phones and the first to use FM broadcast.
The inventor did not know the impact he would have on the world.
Ham radio is enjoyed by so many folks as a hobby and is often times used as a saving grace in times of natural disaster that reliability really becomes important. Obviously reliability is important when the Ham Radio is being activated for public service, but it is also relevant to the hobbyist as well. It can be really frustrating for the Ham that suffers continuously from signal loss.
Knowing what can affect the signal can really help in avoiding some of the pitfalls of Ham operation.
Things You Can’t Control
Certain atmospheric disturbances will cause signal loss and fade. Everyone immediately thinks of stormy weather, but it is not quite that simple. Of course stormy weather will play a roll. Lighting can definitely affect the signal, but so will sun spots. Sun spots or sun flares also will either have the effect to increase or decrease the signal. For example if there are sun flares directly over your geographical area than you are more likely to pick up a longer range signal, when they move on to the other hemisphere away from you than you signal for long range capacity will drop.
Barometric pressure will also affect the signal. In high pressure areas the signal that normally travels through the troposphere -where earths weather occurs, when there is high pressure the signals are pushed down so that the normal waves that are lost into the upper atmosphere become compressed with the radio waves and cause interference.
There are websites that are dedicated to troposphere bending forecasts that predict the patterns of the radio waves used to send ham signals.
Things You Can Control
Antenna placement is the number one thing that is within the Ham’s realm of control. Antenna placement will either make or break the signal reception and transmission. The answer to controlling this situation is simply trial and error. There are predictors that you can pull up online and input your geographical location by longitude and latitude that will give some pretty specific location advice, but keep in mind most of this software doesn’t know how many trees, structures and other obstructions that might be in the way. Even with this professional guidance trial and error will still be important.
Over time the Ham will learn where the best signal is popping through and get the antenna placement right on, but what was best yesterday may not be best today. The answer is being flexible in placement.
Some other things that are in the Ham’s control include equipment, other potential sources of interference like other radios, televisions and cell phones. Although the Ham is forbidden from interfering with any of those signals often times the Ham’s signal is encroached upon by those items.
The best advice for taming frustration from signal loss and fade is to have patience; this is after all supposed to be fun!