" ...Philips 200 Mhz scope... " ... should still see something as that is usually the "3 dB point" for the scope's bandwidth ... I once trouble shot a Tektronix 454 (150 MHz scope) trigger circuit using just a 10 MHz bandwidth Tek portable - the trigger circuit incorporated a tunnel diode that excited a 'tank' circuit that resonated at several hundred MHz ... the indication was only a small 'blip' when the tunnel diode was working as seen on the low bandwidth scope. Take a look at the xmtr with the Philips scope - 433 MHz is just over an octave higher frequency - and the scope should show enough to give a yea/nay indication. Watch out for the the scope probe though - they often have a much lower cutoff freq than the scope itself. You may have to rig a short piece of coax and if the scope has a built-in 50 Ohm termination switch it it to then couple the xmtr output directly into the scope. Zero dBm is about .223 V RMS (.6 V Pk-Pk) less any rolloff in amplitude the scope shows at 433 MHz. Jim P ----- Original Message ----- From: Jilles Oldenbeuving To: Sent: Sunday, May 28, 2000 4:02 PM Subject: [EE] Wireless communication... Hi... For prototypeing purposes we bought a couple of 4 pins 'complete AM radio transmitters' from R.F. Solutions. Also bought a couple of matching receivers ofcourse (433 MHz). (www.rfsolutions.com). My problem with them is this: when supplying Vcc (5V) and GND to the transmitter and connecting a function generator at the data in, of 2 kHz, 50 % dutycycle (coupled AC or DC) i can't see anything at the receiving end. I can't measure if the transmitter is actually oscilating at 433 MHz becouse the fastest scopes we have is a Philips 200 Mhz scope... Also the datasheets and the technical support are far beneath appropiate, in my opinion. The units were places 20 cm apart and had just a wire of 15 cm as an antenna. Anybody couped with the same problem? Anyone have experience with these modules (i mean the AM-RT4-433 transmitter and the AM-HRR-433 receiver, of RF Solutions) Jilles