OBSERVATION OF 433MHz RF SIGNAL USING RIGOL DS1052E
currently working on the said RF freq. i want to see how much the carrier strength. i cannot afford spectrum analyzer, i got Rigol DS1052E (modded to DS1102E), so i utilized that. since it is discussed in eevblog, the DSO will go down to -3dB at around 100MHz, so 400++MHz signal should be badly attenuated. i cannot hope for accurate signal magnitude (if i want, then i have to spend at least thousand dollars for a SA), so i have to bare in mind, that i'm examining the signal qualitatively, or relatively. i want to design a pcb or schematic that can increase the carrier magnitude (but i'm yet to achieve), i'm expecting greater magnitude compared to the signal shown below. i achieved greater signal using stronger power supply as can be seen in the last picture. the setup:
1) make sure your scope capable to sample at 1GHz rate, ie switch off CH2
2) set to peak detect mode, so you can see something at larger timescale.
3) make sure sinx feature is OFF. its just plain useless in Rigol.
4) turn OFF any BW filtering in CH menu.
5) preferably, design your own hi freq lo loss probe and cabling. ie direct BNC connection from circuit to scope is recommended
The best cable is no cable at all - Jim Williams (1948 - 2011)
please bear in mind i only used the standard Rigol probe at 10X on my DIY etched pcb for the pictures below, which will give higher load on the signal... plus the DSO internal BW attenuation and non optimized DIY pcb tracks geometry will shrink the signal even further, as for the track geometry, i'm not sure what improvement should i achieve if i send the pcb to fab house. with proper transmission line, i highly believe i can get higher signal representation, but until then. Enjoy!
no signal (as reference)
the modulated RF signal
using peak detect mode you will see some bandwidth on the bottom side of
digital like (modulation) signal, which i suspect is the 433MHz signal
this is my 433MHz!
any comment, improvement
and suggestion, please contact me at firstname.lastname@example.org
well, too sad if you don't have a back button