Info about QSL

QSL, or QSL card, is the confirmation of a QSO (a radio contact) between two Radio Amateurs.

A QSL card is a (usually postcard-sized) hardcopy, containing the specific details of a QSO. It usually contains the callsign of both operators, the time and date of the QSO (usually in GMT), the radio frequency used, the mode of transmission used, and RST (Readability, Strength, Tone) reports exchanged. RST is a numeric code, that indicates how well (or badly!) the radio signal was received.

Sometimes the QSL card will contain an image, perhaps of something associated with the operator's home town. QSL cards are very important to the Radio Amateur since they confirm that a QSO took place and are used as proof when applying for a Ham Award

Informal designations are also used for some services, especially broadcast radio, but strictly speaking these are not callsigns and there is no guarantee that they are unique. Tactical designators or identifiers (often called tactical callsigns) also fall into this category.

Each country has a set of alphabetic or numeric International Telecommunication Union-designated prefixes with which their callsigns must begin. For example:

Amateur radio callsigns

Amateur radio callsigns normally consist of a one or two character prefix, a number (which sometimes corresponds to a geographic area within the country) and a 1, 2, or 3 character suffix. The number following the prefix is normally a single number (0 to 9). Some prefixes, such as Djibouti's (J2), consist of a letter followed by a number. Hence, in the hypothetical Djibouti callsign, J29DBA, the prefix is "J2", the number is "9", and the suffix is "DBA". In the Italian callsign, IK1TZO, "IK" is the prefix, the number component is "1" and corresponds to the Piemonte region, and TZO is the suffix. Another example is WB3EBO. "WB" is the prefix, the number "3" most often indicates that the station is located in Delaware, Maryland, Pennsylvania, or the District of Columbia. The suffix is "EBO".

Radio frequency, or RF, is a carrier, or alternating current with or without a signal, at a frequency that can radiate, or propagate, if not shielded. Such frequencies account for the following parts of the electromagnetic spectrum:

Very low frequency VLF: 3-30 kHz

Low frequency LF: 30-300 kHz

Medium frequency MF: 300-3000 kHz

High frequency HF: 3-30 MHz

Very high frequency VHF: 30-300 MHz

Ultra high frequency UHF: 300-3000 MHz

Super high frequency SHF: 3-30 GHz

Extremely high frequency EHF: 30-300 GHz

Note: above 300 GHz, the absorption of electromagnetic radiation by Earth's atmosphere is so great that the atmosphere is effectively opaque to higher frequencies of electromagnetic radiation, until the atmosphere becomes transparent again in the so-called infrared and optical window freqency ranges.

Analog signals that are not RF include IF (intermediate frequency) and AF (audio frequency, 20-20000 Hz).

Electrical connectors designed to work at radio frequencies are known as RF connectors. RF is also the name of a standard audio/video connector, also called BNC (BayoNet Connector).

Named Frequency Bands

• Band III - 174-245 MHz

• L-Band - 1.2-1.7 GHz

• S-Band - 1.7-2.4 GHz

• C-Band - 5.8-6.5 GHz

• X-Band - 7.2-8.5 GHz

• Ku-Band - 13.7-14.5 GHz

• K-Band - 21.2-23.6 GHz  
  

The modulation process, is an electronic process, in which the information (like voice for example) is "mixed" to the carrier (the radio wave) and then, after more electronic processes, sent to the antenna for the transmitting.

Of course there is a reverse process, useful to extract from the radio wave the desired information.

If the information is a simple human voice, we may use the following modes:

• AM=Amplitude Modulation (the oldest and first radio transmission mode)

• FM=Frequency modulation (like that used by Hi-Fi radios, transmitting on 88-108 MHz)

• SSB=Single Side Band (more effective system to carry the voice over a radio wave)

If the information is a digital datas, then the modes may be:

• CW=Continuos Wave, that is the "old Morse code" over the radio. This is the very first radio mode used by the men. It is wide used, since it is the best system when there are worst radio conditions.

• RTTY=Radio Tele Type, that means "the oldest teletype writer", this mode is now wide used, since it is very easy to implement with hardware or software

• PSK=Phase Shift Keying, a digital mode, that has a very big advantage over the others, like the less power required for a transmission.

• Packet= this mode permits to exchange data using small packet of data. Each frame (little packet) contains the data exchanged and a set of data that are in the head and in the tail of the packet, used to recnognize the owner and the receiver.

There are also other modes, like the SSTV (Slow Scan TV), FAX (the same as the usual Faxes, but sent via radio), the TCP/IP over radio, and more.

To hear or decode a particular mode, of course the receiver and the transmitter must use the same mode. Elsewere it is impossible to exchange the information between two radio (or TV) stations.

The RST code is used by Radio Amateurs to exchange signal reports.

The "R" stands for "Readability" and is measured on a scale of 1, (barely readable) to 5 (Perfectly readable).

The "S" stands for "Strength" and is measured on a scale of 1, (very weak signal) to 9 (very strong signal).

The "T" stands for "Tone" and is measured on a scale of 1, (very poor tone) to 9 (perfect tone). Tone is used only used in morse code and digimode transmissions and is therefore omitted during voice operations.

An example RST report for a voice contact would be "59", usually pronounced "five and nine," and symbolises a perfectly readable and very strong signal.

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