Sehgal, Head of NCSTC & Director, Vigyan Prasar himself is a ham radio operator (call sign: VU3NKS). The ham radio license exam is known as the Amateur Station Operator's Certificate Examination (ASOC exam).
What do you understand by the word 'phonetics' in amateur radio communication?
What are Q-codes?
What is your position in latitude and longitude (or, according to any other indication) QTH My position is …latitude ……longitude (or, according to any other indication).
What are the designation of emissions allotted to amateur radio service?
R3E: Single-sideband, reduced or variable-level carrier single-channel analogue transmission containing telephony (including audio broadcasting). F2B: Frequency-modulated single-channel telegraphy transmission containing quantized digital information with modulating subcarrier for automatic reception.
Radio Telephony Operating Procedure
So before our transmission, it should be ascertained by sending the message - "Is the frequency in use?". After establishing contact and giving the initial greetings, a signal report must be given to the other station.
Radio Telegraphy Operating procedure
There may be a problem with your friend's station's antenna system that is causing poor reception. In such a situation, giving a false report will only lead your friend astray and your friend may not be able to detect/correct the error in his system.
THE RST SYSTEM
The Indian Wireless Telegraphs (Amateur Service) Rules, 1978
- Short title and commencement
- Definitions
- Necessity for licence
- Categories of licence
- Eligibility for Licence
- Application for licence (a) an individual, or
- Eligibility for admission to Amateur Station Operator's Examination
- Examinations
- Grant of Licence
- Observance of conditions of licence, Convention and rules under the Act
- Period of validity
- Fee for licence
- Authorized frequency bands, power and emission
- Renewal of licence
- Surcharge for late renewal
- Register for wireless telegraphy apparatus
- Location of Amateur Station
- Portable and mobile amateur station
- Amateur Station on board ship
- Loss and Issue of Duplicate of Licence and Document showing the Renewal of Licence
- Transfer of licence
- Operation of licenced amateur station
- Surrender of licence
- Dual holding of licence
- Admission of foreign nationals in examination and grant of licence
- Penalty for breach of these rules
- Repeal and saving
- Use of the Amateur Station
- Messages
- Frequencies, Emission and Power
- Frequency control and measurement
- Non-Interference
- Log (Diary of the radio service)
- Wireless Telegraphy Apparatus
- Secrecy of Correspondence
- 1) General Radiotelegraph and Radiotelephone Procedure
- Inspection
- Powers to take possession of the Amateur Station and to order interception of message
In each of the above cases, the licensee is responsible for complying with this rule. A copy of the Indian Wireless Telegraphs (Amateur Service) Rules, 1978 is kept at the Amateur Station.
Licence No. [See rule 9]
Syllabus of Amateur Station Operator's Certificate (ASOC) Examination for the award of Amateur Station Operator's Licence
The ham radio licensing examination is conducted to ascertain that the person to be a ham radio operator is equipped with the necessary knowledge and skills to communicate using a wireless receiver without causing interference to other radio communication services and according to the agreements decided. in International Communication Meetings. Examination is conducted at Wireless Monitoring Stations (List of Wireless Monitoring Stations can be found in another booklet issued by Vigyan Prasar entitled "Be a Ham! Talk to the World").
Licence I Licence
A person who wants to become a radio amateur must be able to demonstrate his knowledge of both sending and receiving Morse code. The exam is conducted at radio monitoring stations (The list of radio monitoring stations is available in another booklet titled "Be a radio amateur!" published by Vigyan Prasar.
Morse Code Section I
Radio Regulations (a) Knowledge of
Candidates must secure at least 40 per cent in each section and 50 per cent in total to pass. The maximum number of marks is 100 and candidates must secure at least 50 per cent in each section and 55 per cent overall to pass.
MORSE CODE (a) Section I : Morse receiving (Speed: 5 words per minute)
The syllabus for Grade I license is the same as that for Grade II licence, but the written examination for Grade I license lasts two hours. The maximum number of marks is 100 and candidate must score at least 50 percent in each section and 60 percent in total for a pass.
Morse Code
Elementary Theory of Electricity & Magnetism
Current is the rate of flow of charge, that is, the number of coulombs that flow past a point per second. Since DC voltage remains constant (except for the moment when the circuit is closed, i.e. the moment when the switch is turned on), there is no fluctuation in the magnetic lines of force produced across the turns of the coil and no back voltage is generated not. .
Thermionic Emission & Valves
In the triode, current is controlled by means of a voltage applied between the cathode and the grid. 34;crowd" in the space between the cathode and the grid; the valve will be cut off, as no current will flow from the cathode to the anode.
Semiconductors: Diodes & Transistors
Due to the positive potential at the emitter junction, the holes in the p region cross the n region (the base). Due to the reverse bias, current cannot flow in the collector circuit unless current is passed into the emitter.
Radio Receivers
Compare and contrast a Tuned Radio Frequency (TRF) receiver with a Superheterodyne receiver
In a TRF receiver, a series of loosely coupled tuned circuits are used to increase selectivity, and each circuit is put together so that they resonate at the same frequency. But in a superhet receiver this principle is not followed; instead, the RF amplifier, mixer and local oscillator are put together to produce an intermediate product.
How the RF amplifier, Local Oscillator and mixer circuit of a superhet receiver maintains a constant frequency separation and why?
Since we need to tune the RF amplifier section over the entire transmit band, the local oscillator frequency must also be varied in such a way that it always maintains a gap of 455 kHz. The intermediate frequency (IF) is used, which is quite a low frequency because it is the appropriate frequency to achieve the gain efficiency.
Write a short note on 'Selectivity'
Explain the function of each stage a super-heterodyne receiver of briefly
If the RF amplifier section selects and amplifies an 800 kHz signal, then the local oscillator produces a This section further amplifies the audio signals which are finally fed to an output transformer which matches the impedance of output stage with the speaker (in modern transistor receivers the necessity of output transformer is eliminated).
Write a note on AGC or AVC in a superhet radio set
The circuitry of the IF section is designed and tuned to give the optimum gain at that particular IF frequency. The triode/transistor amplifies the audio signal and the volume control potentiometer system controls the intensity of sound.
What is a squelch circuit ?
Write a note on Image Frequency in a superheterodyne receiver set
What is a S-meter?
What is a Beat Frequency Oscillator?
Why ham radio transmissions are not heard in ordinary radio receiver sets? Can you receive ham radio transmissions in your ordinary radio set?
Ham radio talk, if heard on a regular radio, sounds like 'Other Quacks'. Another popular technique for receiving ham radio stations on a regular receiver set is to use two radio sets.
Radio Transmitters
Write what you know about Amplitude Modulation and %ge of modulation
Where VoltageMax is the maximum instantaneous value of the modulation and VoltageMin is the minimum value of the RF carrier.
Why over modulation is not desirable?
What are the Side-bands?
Write what you know about Single Side Band (SSB) transmission?
Why 100% modulation should be aimed in voice transmission?
A relatively low power but well modulated transmitter often produces a stronger signal at a given point than a much stronger but poorly modulated transmitter transmitting at the same distance from the receiver.
Draw the schematic diagram of your intended transmitter and explain its function in brief
In this type of modulator, while the audio (voice) information is impressed on the carrier frequency, at the same time its output gives a signal without the carrier frequency, but still with the two sideband frequencies that carry the voice/audio information. RF power amplification takes place here and this stage is coupled to the antenna system through the antenna impedance matching circuit.
Why crystal oscillators are used and where?
The emf generated by the crystal applied to the grid and cathode produces plate current variations (Ip) in the plate LC circuit. The plate's LC circuit must be tuned slightly higher in frequency than the crystal to produce the necessary phase relationship between the two circuits to maintain oscillation.
Radio Wave Propagation
The AC developed across this LC circuit is fed back to the upper crystal plate through the inter-electrode capacitance, and to the lower crystal plate through the bypass capacitor from the LC circuit. With the crystal and LC circuit oscillating and feeding each other in phase, the entire circuit oscillates as a very stable AC source.
Write a note on Radio Wave Propagation
The behavior of this layer is influenced by time of day, season and sunspot activity. The degree of the curve depends on the angle of incidence of the wave, the ionization gradient of the layer and the frequency of the signal.
What is skip distance?
The F2 layer is the most important layer, which exists at altitudes ranging from 250 to 400 km, and the long-distance propagation of HF all the time is due to this layer. The path that the shortwave signal follows through the F2 layer is actually a curved one.
How do the hams overcome the variable propagation conditions of the ionosphere and the problem of skip?
F1 layer exists at an altitude of 200 km during the day and its characteristics are very similar to E layer which merges into F2 layer at night. Since air density at such an altitude is extremely low, the free ions and electrons (due to the action of ultraviolet radiation from the Sun) cannot.
What is line-of-sight propagation?
Another advantage of VHF is that the size of the VHF equipment is very small. due to its low power as well as miniaturization in the circuit design). We are sure that the above description is sufficient to clear any doubts about the range of a Walkie-Talkie.
What are the two phenomenon significant in line-of-sight reception?
Artificial satellites in space (housing an active electronic relay device), terrestrial relay stations and passive reflectors (the metal plates we see above the hills) are used to extend VHF coverage.
How can you overcome the problem caused by this phase reversal phenomenon?
What is temperature inversion phenomenon as applicable to the line-of-sight communication?
Line-of-sight communication is considered reliable within a short distance (or even for long-distance communication if artificial communication satellites are used) because instead of being on the ionosphere (whose. This is due to the presence of a layer of warm, dry air above a layer of cool, moist air.
What is 'grey line' propagation as applicable to line-of-sight communication?
Line-of-sight propagation is limited to the optical horizon and is only about 75 miles for frequencies above 30 MHz; but in the spring or fall, or sometimes in the summer, this extension of the field of vision is found to extend to about 500 miles.
What is a critical frequency?
What is a beacon?
What is the difference between Fade-out and fading?
Unlike attenuation, attenuation is a constant change in the received strength of a radio wave. It is caused by multiple reflections from the ionosphere, which cause two or more waves from the same transmitter to travel along different paths of different lengths and therefore differ in phase and amplitude when they reach the receiving antenna.
Aerials
Write a general note on aerials
What are the different types of antenna system used by ham radio operators?
Describe the working function of a horizontal dipole antenna
Why half-wave dipoles are fed at the centre?
What is VSWR (Voltage Standing Wave Ratio) ?
When the impedance of the load (antenna) matches the impedance of the transmission line, there will be no standing waves. The VSWR on the transmission line is due to the power reflected from the antenna back to the transmitter.
What is 'radiation resistance'?
VSWR is greater than one for a mismatched system and equal to one for a perfectly matched system. If PF is the forward power and PR is the reflected power measured in watts by a directional wattmeter, then VSWR can also be calculated by the formula:
Why impedance matching is necessary in an antenna and transmission line system?
What are current fed and voltage fed antennae?
When the excitation energy from the RF source is input at the point of maximum voltage, the antenna is said to be a voltage-fed antenna. The impedance at the end of the antenna is high or it is the high impedance point.
Write about different types of antenna system impedance matching procedure
One important reason is that a large group of radio amateurs still love Morse code. Morse code can be easily learned if we use certain techniques to remember the codes.