I thoght i put your circuits, i make mistake....
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Hello, can somebody help wich transistor is like bfg520
- Thread starter michael1978
- Start date
HELO, why nobody say something i make circuit like you said
, and is not working
, and is not working
Sorry, I don't understand your last post.HELO, why nobody say something i make circuit like you said
to make FM receiver
I make to work my circuit is working perfect the filter and everything, just one problem if you can help me, i can change the frequency from 90 to 100 this my pronblem now, can you help only with this also
here my schematic
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Because that sir he make the same, and i make mistake, i was looking one more time his schematic, after i change like him, i just add C10 also, i make experiments, and i did it, now i have only the problem with tuning, i put the voltage probe to chathode, i just change 90 to 100 i think, you said t put the probe to cathode so i did
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Sorry, if you are referring to my circuit, yours bears little resemblance. If the filter is to reduce some of the harmonics, a tuned collector load will do the same without the complications of the unmatched filter you are trying to incorporate. I had a quick go and achieved -48dB for the second harmonic.
You are on your own for a few days.
Sir i go to sleep, but now stay the problem in the tuning, i dont know what to do of like that is normal, what do you think? goodnight.
Are you trying to say that you can't tune the circuit?
Yes, i put the probe to the cathode of varicap, and i change to voltage...the tuning is from 90 to 100Mhz? is that normal? of what i have to do, i try also with BB515? but is not working
Tuning range seems OK. My simulation work with the BB515.
Have you built a physical circuit?
I change the varicap BB515 now is rom 89Mhz to 101Mhz, if its okey local oscillator, so you think is ok, soi gonna buid tomorow(i hope)
thnx for helphello you want to say is not normal?
No.
Please study Superheterodyne Receiver Operation. The local oscillator must be the IF frequency below or above the received radio station frequency. The IF frequency of most FM radios is 10.7MHz so read my previous post for the frequency ranges of the local oscillator.
Sorry one more question, how m
Hello Audioguru if i wanna change my varicap voltage i can get this result from 76 to 97mhz,
BUT NOW AT THE OUTPUT OF Q2 is going from 88Mhz to 108Mhz, when i change the varicap value, is right now?
I remove lpf , so now tuning to transistor q2 is from 88 to 108Mhz, is okej now to build, normal when i change the value of varicap i get those result
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