To make LC filter work effectively, termination impedances for passband and stopband are very important.
Digital wrote on May 20th, 2010, 1:11am:The transmitter is all surface mount based around the SX1230 chip.
Show me output reflection coefficient of transmitter by network analyzer measurement.
Digital wrote on May 20th, 2010, 1:11am:Ive built two 5 element low pass filters with SMA in and out connectors and tested them with a spectrum analyzer with tracking gen.
Both perform well with less than 1 db of insertion attenuation at 433mhz and around 25 db at 860mhz.
Show me S-parameters(S11,S12,S21,S22) of one LPF and cascaded two LPF.
Digital wrote on May 20th, 2010, 1:11am:The problem is when I test them with my transmitter there seems to be no visible reduction in the harmonics when viewed with the spec ann.
What do you mean by "
ann" ?
Don't use unfamiliar abbreviation.
Try to insert lossy matching pad between transmitter and LPF or between two LPFs.
http://www.rfcafe.com/references/electrical/attenuators.htm