AMATEUR RADIO IN MARINE

AMATEUR RADIO IN MARINE


In marines, Marine single side band(SSB) radios are preferred to Ham radios for communication .Choosing between either of them depends on an individual.The Marine MF/HF-SSB radio is a transceiver more like a VHF radio.The main difference is in its operating frequency.Marine radios operates in the range of 1.6MHz-30MHz.In VHF radios there is only line of sight communication,while the MF/HF radios refract the signals within atmosphere hence providing increased range and long distance ship to ship or ship to shore communication.

When the distance of communication is more than 30 NM,the MH/HF radios maintain the communication lifeline .Along with the long distance communication the SSB radios provide with options like email, teletype and weather
facsimile .The recent SSB radios allow access to amateur frequencies for those boaters with license.Since HF radios use lower frequencies to communicate over long distance at relatively low cost they are most popular for blue water passage maker or world cruiser.
       
       Propagation is one of the key factors which helps HF radios in effective communication.Propagation is simply the reflection or refraction of radio waves in the layers of ionosphere.Ground wave propagation is ideal for lower frequencies (up to 3MHz) and relatively short distances during daytime (100-200NM) and up to 400NM at night.In sky wave propagation the signals refract through a layer of ionosphere and then back to the earth.Hence longer distances can be achieved,often thousands of miles during the day and several thousands miles at night.

Conditions to be considered in frequency selection are

 The higher the sun above the horizon the higher the frequency you will need to communicate.
 For the same frequency you can generally communicate further at night than during the day.
 Winter are preferred to summer for improving the distance you can communicate.

 The higher the frequency, the further you can communicate.



As a general rule, ship to ship communications are carried out on simplex frequencies where both transmit and receive frequencies are the same. Duplex frequencies on the other hand are intended for use as ship to shore frequencies although simplex frequencies can also be used for this purpose.


LICENSING

In order to use a marine SSB the ship needs a call sign from the federal communication commission(FCC) ,called a station license which is good for ten years.One also need to obtain an operator’s permit,called restricted operator permit,a lifetime license to use SSB marine radio abroad.

AMATEUR RADIO IN DEFENCE SERVICES

AMATEUR RADIO IN DEFENCE SERVICES

          The dot and dash communication through amateur radio in military services started from the world war era.During the world war-I, the radio communications seemed to be the most critical mode of communication. An organistion was formed in the name of AUXILLARY AMATEUR RADIO SYSTEM (AARS) by the United States army signal corps. This was more helpful in gathering the manpower and war equipments during the 1st world war.The AARS employed accomplished amateur radio enthusiasts.The AARS was a partially successful effort.
          The AARS was reborn in the name of MILITARY AFFILIATE RADIO SYSTEM. This was due to the growing number of civilian service volunteering of people.Eventually Navy-marine operations ,separate army and air forces with MARS began on 1st January 1963. MARS served its best during the Korean war,Vietnam war and the Gulf war helping the servicemen to contact their  families from oversea areas. The program again changed its name to MILITARY AUXILARY RADIO SYSTEM and continued its services. MARS is an active body till date and extends its support to the defence and military departments to the fullest of its ability.

DIGITAL MEDIA DISCRIPENCY

         Having a digital media portal falls into both the pro and con aspects for any country’s defence and military departments. However there are laws framed that restrict the usage of social media platforms by the soldiers.the digital media keeps the soldiers in contact with their family and friends and provides numerous benefits even after the retirement of the army person.But the con aspects dominate more in this case. Operation security is the major thing that gets affected when the soldiers share their location.The digital media allows a person to post anything of his/her heart’s desire,which will not be suitable for an army personnel.
          Defence services cannot depend only on electronic communication. At times face to face communications are necessary but that does not serve to be a confidential platform. Making the soldiers understand the consequences of posting things would compensate the the con effects of the digital media platform.Here comes the saviour of military secrets i.e. the amateur radio communication


MILCOM MONITORING RECIEVERS:

      Usually milcom frequency ranges are not published. For monitoring the mil com activities one must search the frequency range of 225-380MHz. Monitoring the civil air band is quite a difficult job as the conversations are much shorter or sometimes in Morse codes. One could also monitor 380-400MHz frequency range for areo operations during the war times.There are many Milcom monitoring equipment , antennas and SDR are being setup to monitor the milcom activities.But it is very difficult to search the whole band of frequencies.

         The military details are much confidential and hence much information regarding the VHF and UHF bands are not disclosed. The MARS and other such organizations serve to be a point of contact to the soldiers and the public. The HAM enthusiasts serve the defence by capturing the frequencies of the terrorists and the anti world peace organizations. Therefore the HAM serves to be a great hobby and matter of serious business. 

Amateur radio in space

Amateur satellite service is a project sponsered by various entities and carried out by astronauts and cosmonauts on International Space Station who have license. Shuttle Amateur Radio Experiment (SAREX) was its previous name.
Amateur radio operators all over the world speak with astronauts with the help of  their mobile, home radio stations. To establish communication low power radios and small antennas can be used. Even with the help of laptops it is possible to send digital data to space station.
The space station occupants while working have breaks. During break, some of them spend time communicating via amateur radio.
With the help of amateur radio, we can communicate with astronauts in space. This is very useful to students as they get connected with astronauts so that they could learn more new concepts and develop their knowledge.
How to Call Space Station Astronauts on the Radio?
A ground station contains a device capable of both transmitting and receiving radio waves near the 145 megahertz frequency. The ISS radio transmits signals at 145.80 MHz and receives signals at either 144.49 or 145.20 MHz, depending on its orbital location.
During the 10-minute communication sessions, Ransom said, students usually ask the ISS crew what they do in their free time, where they are and what it looks like out their window.
Thus amateur radio in space is very useful and is one among the best methods to communicate with astronauts in space.

History of Ham

The birth of amateur radio starts, of course, with the invention of the radio. There are many contributors to the birth of radio such as Guglielmo Marconi, Nikola Tesla, ect. Brilliant Scottish scientist named James Clerk Maxwell set the next foundations in place.Maxwell was a theoretical scientist and sought to express physics in terms of mathematical relationships.
Maxwell's work culminated in 1873 with the publication of a book called "A Treatise on Electricity and Magnetism". In this he developed equations, now known as Maxwell's Equations that defined electromagnetic waves.

 No matter who gets the credit, one thing is clear, these first radio operators were the pioneers of amateur radio. In fact, by 1909, the first amateur radio club, The Junior Wireless Club, was organized in New York. The earliest transmitters consisted of spark transmitters and these continued to be used for many years. It was only in the 1920s with the cost of valves / tubes coming down that spark transmitters stopped being used. The phenomenon of radio waves gained a lot of publicity - the fact that signals could travel between two points with no wire even held a form of magical mystery and public demonstrations were sometimes given. These factors provoked people to learn about radio communication and to become radio amateurs.

In the early days in the history of ham radio it was not envisaged quite how radio would develop. Anyone was allowed to transmit and there was no regulation. However as radio started to be used for commercial uses it was agreed that licensing would be required. In the UK licenses started to be issued in 1904, and this occurred around the same time in many other countries. Callsigns also started to be issued, but this occurred a little later. As the years passed, the history of amateur radio showed that technology developed and new techniques were used. However the same pioneering spirit of some of the early radio amateurs was retained, with many radio hams contributing to the development of technology in many ways.

Events:
 It was the sinking of the RMS Titanic on April 15, 1912 that prompted new international radio laws which also affect amateur radio, including frequency restrictions and operating procedures.

World War I: By 1917, World War I had put a stop to amateur radio. In the United States, Congress ordered all amateur radio operators to cease operation and even dismantle their equipment.These restrictions were lifted after World War I ended, and the amateur radio service restarted on October 1, 1919.

World War II: During the German occupation of Poland, the priest Fr. Maximilian Kolbe, SP3RN was arrested by the Germans. The Germans believed his amateur radio activities were somehow involved in espionage and he was transferred to Auschwitz on May 28, 1941. After some prisoners escaped , the Germans ordered that 10 prisoners be killed in retribution. Fr. Kolbe was martyred when he volunteered to take the place of one of the condemned men. He is considered the Patron saint of Amateur radio operators.
Again during World War II, as it had done during the first World War, the United States Congress suspended all amateur radio operations.

NATO Alphabets

Can you hear me now?
Are you able to hear me now?
If what you've got maybe this failure to communicate, then it may indicate that it’s time to place the NATO sound alphabet to use. Anyone who’s worked with the military is conversant in it. Even civilians may use a variation when they’re trying to be understood over the phone.

The NATO sound alphabet was adopted within the 1950s. The 26 codewords are assigned to the 26 letters of the English alphabet. Several variations of spelling alphabets have existed through the years The sound alphabet we hear commonly today was adopted for radio communication by the International Maritime Organization in 1965.

The NATO sound alphabet is employed today in military communication and radio communication, whether you’re trying to be understood across time zones or across space. Why the necessity for a phonetic alphabet? If you think that you've got a loud office, just imagine trying to signal military landing locations amid gunfire and radio interference. Every letter counts and clear communication just might save lives.

To create a sound alphabet, you merely replace the letter that you simply want to mention with a word that starts with an equivalent letter, an idea which is named acrophony. For example:

‘C’ is often replaced by ‘Charlie’.
‘G’ is often replaced by ‘Golf’.
‘O’ are often replaced by ‘Oscar’.

Some phonetic alphabets use code words that revolve around a selected theme; for instance, several older alphabets used names of cities and countries as code words (e.g. ‘Amsterdam’ and ‘Italy’). Other phonetic alphabets use code words which are supported other factors, and most notably on intelligibility, which reflects how easy the code words are to know in conditions where it’s difficult to speak (e.g. ‘Able’ and ‘Baker’).

There are two main advantages to learning the NATO sound alphabet today compared to other alphabets:
• The NATO alphabet is that the main sound alphabet employed by many countries, organizations, and individuals around the world, meaning that tons of individuals, and particularly those that encounter it during a professional setting, are likely to be conversant in it. Accordingly, this is often the sound alphabet that folks are presumably to simply understand if you employ it to speak to them, and it’s also the sound alphabet that folks are presumably to use when lecturing you.
• The specific codewords within the NATO sound alphabet were chosen supported extensive testing, as they ensure mutual intelligibility between speakers from different linguistic backgrounds, by virtue of being easy to pronounce and recognize.


Accordingly, the NATO sound alphabet consists of 26 codewords, each of which represents a special letter of the English alphabet.
These words are:
Alpha, Bravo, Charlie, Delta, Echo, Foxtrot, Golf, Hotel, India, Juliet, Kilo, Lima, Mike, November, Oscar, Papa, Quebec, Romeo, Sierra, Tango, Uniform, Victor, Whiskey, X-ray, Yankee, Zulu.

In the NATO alphabet, punctuation marks are mentioned by their name, with a couple of exceptions: a hyphen (-) is mentioned as a touch, a period (.) is mentioned as a stop, and a percentage point is mentioned as some extent or as a decimal.

If you opt you would like to find out the NATO sound alphabet, you'll roll in the hay employing a sort of methods, like by writing down the code words on handmade flashcards, or by employing a memorization software. you'll also prefer to simply memorize the code words so as, employing a list of the code words within the NATO sound alphabet. Potentially, you'll recite these words with a rhythm or tune that creates the code words easier for you to recollect, though this isn’t crucial.

The next time you’re having a Whisky Tango Hotel moment, you'll thank military communicators for helping you get your point across more clearly.

J POLE ANTENNA

J POLE ANTENNA:
    J pole antenna is one of the popular antenna with 2meter in height commonly used in amateur radios particularly on VHF and UHF bands. It was fi invented by Hans Beggerow in 1909. It was used in zeppelin airships. It is end fed vertical half wavelength antenna. It is also known as J antenna and end fed zepp. It is omnidirectional in nature. When j pole antenna is properly connected , it clearly makes good match for 50 ohm coaxial transmission line. Commonly impedance matching is done for J pole antenna. The transmitter is matched to output impedance by a series band section of transmission line. The Jpole antenna is more sensitive to metal objects in surroundings. This is due to lack of true ground plane. This can be reduced by feed polarity. It can be avoided by making a distance of one or two wavelength away from filling cabinets.
                           

     J pole antenna is of different types,
• Roll up emergency J pole
• Copper pipe J pole
• Fold up copper pipe J pole
• Double Jpole
• Super J pole
  Roll up emergency antenna is trivial to build. The disadvantage of this antenna is , fairly fragile and has narrow bandwidth because of small diameter of the wires. The bandwidth can be increased by the usage of ladder line for impedance match. And also by connecting piece of coax to the radiating part. The construction of copper pipe J pole is ease for durability and bandwidth. Fold up copper pipe J pole antenna is too large and hard to carry. It  has small durability. The antenna which consist of number of half wavelength vertical elements separated with half wavelength tuning stubs feed with folded matching stub is called Super J pole antenna. It is co-linear vertical antenna .

MONOPOLE ANTENNA

MONOPOLE ANTENNA

A monopole antenna is a type of radio antenna consisting of a straight rod-shaped conductor, placed  perpendicularly over some type of conductive surface, called a ground plane.

 The monopole antenna was invented in 1895 by  Guglielmo Marconi; for this reason it is sometimes called the Marconi antenna. Common types of monopole antenna are the whip, rubber ducky, helical, random wire, umbrella, inverted-L and T-antenna, inverted-F, mast radiator, and ground plane antennas.The monopole antenna is an common antenna that is often used on vehicles and other areas were a large conductive flat area is present (“ground plane”). The standard monopole antenna measures 1/4 wavelength in height (λ/4); however, this antenna must be placed on to a large conductive surface to function properly.

The length of the antenna is determined by the wavelength of the radio waves.  The most common form is the quarter-wave monopole, in which the antenna is approximately one quarter of the wavelength of the radio waves. A monopole antenna has an omnidirectional radiation pattern: it radiates with equal power in all azimuthal directions which means horizontal angle measured clockwise from any fixed reference perpendicular to the antenna

POLE BROADCASTING ANTENNA

While using radio broadcasting, the radio frequency power from the broadcasting transmitter is fed across the base insulator between the tower and a ground system. The ideal ground system for AM broadcasters comprises at least 120 buried copper or phosphor bronze radial wires at least one-quarter wavelength long and a ground-screen. All the ground system components are bonded together, usually by welding, brazing or using coin silver solder to help reduce corrosion. Monopole antennas  uses guy-wires for support which is named as masts in some countries. In the United States, the term “mast” is generally used to describe a pipe supporting a smaller antenna, so both self-supporting and guy-wire supported radio antennas are simply called monopoles if they stand alone. If multiple monopole antennas are used in order to control the direction of radio frequency (RF) propagation, they are called directional antenna arrays.