Sorry for using the vague term “decent power meter”. I meant something like an HP 435/436 with an 8481A measurement head.

The Bird instruments are intended for measuring rather larger RF powers and, as Bob says, do not offer the accuracy required for testing a signal generator.

While writing, a tip to avoid the mistake I once made. Power meters are, of course, broadband. Therefore if the signal to be measured has significant harmonic content an error in measuring the fundamental power will result. Forgetting about this, I was puzzling why the Cal. outputs of my 8560 series and 8590 series spectrum analysers measured differently. Then I realised that the 8590 Cal. source has strong harmonic output, whereas the 8560 series source does not.

Similarly, some signal generators that use frequency doublers produce strong half-frequency outputs which would cause an error when checking output power on the highest frequency range with a power meter.

Regards,

Alwyn