I have several UHF "bugs" and I wish to understand several things: All the bugs I have work on the 433MHz band. SMD components. Several use a simple metallic case crystal, U49, and several use SMD components only , and I suppose they work on the third overtone and then doubled, meaning I think the crystals are around 87MHz. The SMD components have 4 "legs" - no idea which kind of crystal is this one, or it may be even an oscillator I cannot debug it to know which kind of device is it. I need your help, maybe someone may know this device:
4 legs - one from each side, black, about 6mmx4mm. All I could do is to measure the frequency with a counter - at 3 legs it showed me 433.9MHz - but I'm not 100% sure the signal I read it's not from the PCB. I'll be very thankful for any help - maybe a link to similar device. It confuses me very much, as it is written 480 on it - no doubt, but it works on 433.9MHz - so it has no sense. As it uses only 3 transistors and 1 diode - which I guess it's a varicap (maybe a PIN diode), it's a "miracle"... 2 AF transistors and one (the one which you can see at the end of the PCB - and it's "deleted" or in any way I cannot read what is written on it) - I suppose it's an RF amp.... It doesn't make me any sense... But I'm not a "pro" in CCOs... Please take a look here:
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