The "PSB" signal report

A PSB (Print, Strength, Bandwidth) report is proposed for PSK communications to ensure a more meaningful exchange occurs, where:

Print is an estimate of average error free text decoding on the screen

Strength looks at waterfall trace or spectrum amplitude relative to noise

Bandwidth refers to visible signal width on the waterfall or spectrum, with excessive bandwidth interpreted by the presence of additional unwanted sidebands

S meters measure the average strength of all signals in the receiver passband. So for situations where multiple signals are present, and NB IF filtering is not applied, then a visual measure of relative waterfall trace or spectrum amplitude is more meaningful for the strength of the decoding signal.

When viewing the bandwidth of very strong signals, well-suppressed additional sidebands may be seen above the noise floor. In this case, an IMD reading may assist in determining their status. If the IMD reading is about –25db or better, then any additional sidebands can be assumed as below the interference threshold, disregarded, and a B9 report given. If the IMD reading is about –20db or worse, then the additional sideband modulation is undesirable, may cause interference to other stations, and an appropriate value from the bandwidth table can be applied to the report.

It is suggested that IMD readings only be given to the other operator when requested, and then only as a supplementary report. This is because IMD is only valid for strong signals at idle, and after careful adjustment of receiver settings. However, an IMD measurement at the transmitter can be accurately undertaken, and is an excellent way to verify that the station setup is optimised.

Click here for a further discussion on IMD measurement.

 

The format of the 3 data elements of a PSB report continue to satisfy the traditional RST requirements for manual and computer logs, QSL cards and PSK software.

For simplicity, not all numeric designators are used for Strength and Bandwidth reporting; however there is no reason why operators cannot use all the available numbers, but no additional descriptors are proposed.

Where an unfavourable bandwidth report is received during a QSO, it is expected that further discussion on the width of the signal would follow.

A suggested checklist is available here for station system setup to avoid excessive bandwidth.

Click here to see and hear BPSK31 signals of normal and excessive bandwidth.

PSB, being a radically different reporting term, will demand more attention than the common RST format, and is expected to encourage more meaningful reports and help clean up poor signals on our bands.