El 06/03/2010 11:28, g4ilo escribió: > I was listening down around 14.077, just above some slow FSK mode which I > think is JT65A. The JT65A was tuned quite low pitched in my receiver, and I > could clearly see "images" of it over to the right. Judging by the spacing of > the "image" tones I was seeing an audio third harmonic of the original > signal. The image tones were clearly visible and would have been copyiable in > their own right if not for the 3x spacing. > > My transceiver is a K3 and the signal was just an S9 so overload or intermod > are unlikely to be the issue, but to make sure the images weren't being > generated this end I tuned in some strong RTTY and found no harmonic images > of the signal. > > Has anyone else seen this? Aren't the tones supposed to be generated at such > a frequency that any harmonics are cut off by the SSB filter? > > Julian, G4ILO >
I have not seen that particular case. But the radio should be driven at a reasonable lever where harmonics or unnaceptable IMD products are not created. A SDR, becoming so common nowadays, cannot rely on the filtering of hardware radios. Jose, CO2JA
