To show exactly where the harmonics will get into for any frequency selected in the FM band here's a calculator to show all the harmonics but we should be concerned with the first 10 mostly. Just enter the frequency in mHz and see where the harmonics would be.
http://mustcalculate.com/electronics/harmonics.php?f=107.5M
http://mustcalculate.com/electronics/harmonics.php?f=88.5M
Absolutely.
And in addition to harmonics we also talk about 'spurs'. By this we mean 'spurious', extraneously generated unwanted stray signals. Well designed transmitters do not produce spurs, but Wholehouse FM transmitters are loaded with spurs.
@carl-blare I was at Ultratech, a certification lab here near Toronto and the testing for certification is done with gear costing hundreds of thousands$$$ and the transmitter is in an anechoic chamber and would love to have taken a Wholehouse 3 and show the certification and see what the techs reaction would be. I watched the attempts to get a transmitter to pass certification and see how hard it is, then I see the Wholehouse 3 and wonder how it got passed.