Is it possible to measure a 433MHz RF Transceiver signal using a 100MHz Oscilloscope? At least to see if it is transmitting or not
Following on from PlasmaHH's comment - yes, absolutely use RTL-SDR. For that you will need:


an RTL-SDR compatible tuner (search eBay for RTL2832U - should be around $10)
an RTL-SDR software package - I use gqrx


Set up gqrx according to the instructions on its website, and then set the centre frequency of the display to 433 MHz (actually probably more likely 433.92 MHz - take a close look at the label. Be sure to enable automatic gain control and you should see bursts when you transmit using your source.

You may see some aliased signals on a 100 MHz scope, but you can't trust them as they are outside of the scope's spec. Use RTL-SDR - it's what I use for debugging 433 stuff and it has never failed me.