I just thought you might be interested in the saturated carrier
output tests I have been doing recently on DATV-Express.
There is a 3dB resistive pad on the output of the board for
the protection of the board and better termination of any
Frequency MHz Power dBm
The lowest frequency I could get the board to lock was
65 MHz and the highest frequency 2.5 GHz.
I also have a set of preliminary data for carrier leakage and
unwanted side band suppression. The testing methodology
used by me was a bit suspect but the figures are in line with
the figures quoted by the manufacturer of the modulator
chip and are more than adequate for DATV.
I have also been playing with Evanescent mode wave-guide
filters for 5.7 GHz. These are simple to build filters that use
the cutoff effect of waveguides and resonators made from
the inductance of the wave-guide and the capacitance of a
tuning screw. Unlike most of the articles on this topic I have
not used surplus wave-guide (which I could not find) but
instead have used stock rectangular aluminium tubing and
brass bolts. I shall revisit this topic at a later date.