WHAT IS SINPO CODE ???????????????

SINPO, acronym for signal, interference, noise, propagation, and overall, is a code used to describe the quality of radio transmissions, especially in reception reports 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

Code explained

S (Signal strength) 

The relative strength of the transmission.

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.

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