Po' boy Spectrum Analyzer

[Bluerunner]

An all band manually tuneable shortwave radio receiver will easily let you know if you are wasting power transmitting harmonics and bleeding over.

Tune in on the frequency you are transmitting on, then tune above and below it and see if you hear yourself on other frequencies too. Try it barefoot and amped.

Tune way above and below the transmitted frequency, well into the other bands and you may be surprised how far across the spectrum you are throwing trash.

Change the length or shield the receivers antenna as needed to get the received signal amplitude into a usable (full scale) range.

I use a Yaesu 747 modded for all band. The S meter gives a relative field strength reading handy for comparing the effectiveness of band pass filters.

Even the cheap "transistor radio" type shortwave receivers will do but most don't have an S meter. The thing is that if you can hear your signal anywhere but the frequency you are transmitting on you probably have a problem.