ITC Bridge Forum: EVP Receiver

[Fox_Malder]: Hello friends All good health! We have found a new type of EVP unit, attach the scheme, if there are questions I ask to write on the site in this topic http://www.tmlink.ru/forum/showthread.php?t=492&page=2 [Vicki Talbott]: Oh, boy. That looks complicated to me. Thanks so much for posting the link. Vicki [Fox_Malder]: Hello my friend! This is not a complicated scheme, I can help, turning the there is nothing complicated [Vicki Talbott]: Well, that is good news! I can have a radio wizard take a look at it with me. Will keep you posted. Thanks, Vicki [oldman]: I know this is an Old thread, but values the the transistors and impedance values for the coils would make a world of difference. [Jan]: I thought the circuit was upside-down, then realised they are PNP transistors and +ve is at the bottom! There appear to be some errors in the design as shown. D1 zener is shorted by the BE junction of T2. (D1 has no voltage associated with it anyway) P3 will do nothing because there is a DC block C9. Looks like an unnecessarily complicated tuned circuit at the input. No values given for L1/L2. No transistor types. Zener D2 no voltage given Reverse image search gives transistors as: T1-KT3107 BC556 ew. BC212 (PNP) T2-KT3102 BC547 (NPN) T3-KT3107 BC556 ew. BC212 (PNP) Looking carefully, zener D1 is probably used a noise diode. Looks like some very noisy radio receiver with the sort of noise where you can imagine you can hear

voices mixed with any radio signals. Are the dual tuned circuits supposed to be some scalar-wave stuff? Last edited on Oct 25th, 2016 07:15 PM by Jan