SINPO
Encyclopedia
SINPO, acronym for signal, interference, noise, propagation, and overall, is a code used to describe the quality of radio
transmissions, especially in reception report
s written by shortwave listeners
. Each letter of the code stands for a specific factor of the signal, and each item is graded on a 1 to 5 scale (where 1 stands for very bad and 5 for very good).
The use of the SINPO code is subjective and varies from person to person. Not all shortwave
listeners are conversant with the SINPO code and prefer using plain language instead.
I (Interference
) : Interference from other stations on the same or adjacent frequencies.
N (Noise) : The amount of atmospheric or man-made noise.
P (Propagation
) : Whether the signal is steady or fades from time to time.
O (Overall merit) : An overall score for the listening experience under these conditions.
The SINPO code in normal use consists of the 5 rating numbers listed without the letters, as in the examples below:
54555 - This indicates a relatively clear reception, with only slight interference; however, nothing that would significantly degrade the listening experience.
33434 - This indicates a signal which is moderately strong, but has more interference, and therefore deterioration of the received signal.
Generally, a SINPO with a code number starting with a 2 or lower would not be worth reporting, unless there is no noise, interference or loss of propagation, since it would be likely the signal would be unintelligible. This does not apply to shortwave stations broadcasting on SSB, however, as there is no carrier signal to receive.
One shortwave listener (SWL) may rate a signal as 33232 while another SWL at a different location might rate it as 44333. Although the original SINPO code established technical specifications for each number (i.e., a number 3 in the P column meant a fixed number of fades per minute), these are rarely adhered to by reporters. The 'S' meter displays the relative strength of the received RF signal in decibels; however, this should not be used as the sole indication of signal strength, as no two S meters are calibrated exactly alike, and many lower-priced receivers omit the S meter altogether. References to a "SINFO" code may also be found in some literature. In this case, the 'F' stands for Fading, instead of 'P' for Propagation, but the two codes are interchangeable.
Some listeners may not be able to distinguish between the 'I' which indicates interference from adjacent stations, and the 'N' which describes natural atmospheric or man-made noise; also for some listeners, the rating for 'Propagation' may not be completely understood. Various books and periodicals maintain the original SINPO code as being the only one for DX reporters. However, many stations suggest the SIO code -- a simpler code which is used by most professional monitoring stations around the world.
Radio
Radio is the transmission of signals through free space by modulation of electromagnetic waves with frequencies below those of visible light. Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space...
transmissions, especially in reception report
Reception report
A reception report is a means by which radio stations receive detailed feedback from their listeners about the quality and content of their broadcasts...
s written by shortwave listeners
Shortwave listening
Shortwave listening is the hobby of listening to shortwave radio broadcasts located on frequencies between 1700 kHz and 30 MHz. Listeners range from casual users seeking international news and entertainment programming to hobbyists immersed in the technical aspects of radio reception and DXing...
. Each letter of the code stands for a specific factor of the signal, and each item is graded on a 1 to 5 scale (where 1 stands for very bad and 5 for very good).
The use of the SINPO code is subjective and varies from person to person. Not all shortwave
Shortwave
Shortwave radio refers to the upper MF and all of the HF portion of the radio spectrum, between 1,800–30,000 kHz. Shortwave radio received its name because the wavelengths in this band are shorter than 200 m which marked the original upper limit of the medium frequency band first used...
listeners are conversant with the SINPO code and prefer using plain language instead.
Code explained
S (Signal strength) : The relative strength of the transmission.I (Interference
Interference (communication)
In communications and electronics, especially in telecommunications, interference is anything which alters, modifies, or disrupts a signal as it travels along a channel between a source and a receiver. The term typically refers to the addition of unwanted signals to a useful signal...
) : Interference from other stations on the same or adjacent frequencies.
N (Noise) : The amount of atmospheric or man-made noise.
P (Propagation
Radio propagation
Radio propagation is the behavior of radio waves when they are transmitted, or propagated from one point on the Earth to another, or into various parts of the atmosphere...
) : Whether the signal is steady or fades from time to time.
O (Overall merit) : An overall score for the listening experience under these conditions.
Examples of SINPO code applied
In responding to a shortwave reception, the SINPO indicates to the transmitting station the overall quality of the reception.The SINPO code in normal use consists of the 5 rating numbers listed without the letters, as in the examples below:
54555 - This indicates a relatively clear reception, with only slight interference; however, nothing that would significantly degrade the listening experience.
33434 - This indicates a signal which is moderately strong, but has more interference, and therefore deterioration of the received signal.
Generally, a SINPO with a code number starting with a 2 or lower would not be worth reporting, unless there is no noise, interference or loss of propagation, since it would be likely the signal would be unintelligible. This does not apply to shortwave stations broadcasting on SSB, however, as there is no carrier signal to receive.
One shortwave listener (SWL) may rate a signal as 33232 while another SWL at a different location might rate it as 44333. Although the original SINPO code established technical specifications for each number (i.e., a number 3 in the P column meant a fixed number of fades per minute), these are rarely adhered to by reporters. The 'S' meter displays the relative strength of the received RF signal in decibels; however, this should not be used as the sole indication of signal strength, as no two S meters are calibrated exactly alike, and many lower-priced receivers omit the S meter altogether. References to a "SINFO" code may also be found in some literature. In this case, the 'F' stands for Fading, instead of 'P' for Propagation, but the two codes are interchangeable.
Some listeners may not be able to distinguish between the 'I' which indicates interference from adjacent stations, and the 'N' which describes natural atmospheric or man-made noise; also for some listeners, the rating for 'Propagation' may not be completely understood. Various books and periodicals maintain the original SINPO code as being the only one for DX reporters. However, many stations suggest the SIO code -- a simpler code which is used by most professional monitoring stations around the world.