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  1. Miguel Lopez

    The Great CRT to Oscilloscope Project!

    Has that CRT electrostatic deflection? I mean, most TV CRT had electromagnetic deflection, and that is not suitable for a high frequency operation, which would be required in an oscilloscope. If the CRT has no electrostatic deflection, I guess you won't be able to swith between both deflecting...
  2. Miguel Lopez

    Hurricane help

    Good idea. I will try AA to replace C type batteries using styrofoam, they should fit well
  3. Miguel Lopez

    1 Mhz oscillator needed

    I support Zork's words. Use a xtal. If you don't have a 4060 ic, then you can use a 1MHz xtal and build the oscillator using inverter gates.
  4. Miguel Lopez

    Amplitude Modulation using Op Amp.

    Now I got it. Thanks. This is what I got passing true AM signal throught the same RC filter (1nF, 50ohm) Blue trace: Signal before the filter. Red trace: Signal after the filter. It can be seen that audio signal has the same ratio (+/-) relative to the carrier in both cases. Anyway, I found...
  5. Miguel Lopez

    Amplitude Modulation using Op Amp.

    Thank you very much for the explanation, duke. I'm gonna try to do the Fourier analisis to both kind of signals. I intend to mount a simple circuit in a protoboard to see what happen. I will use the FET that you sent me mounted on a little PCB. Yes, I know Op-Amps are limited in bandwidth, I...
  6. Miguel Lopez

    Amplitude Modulation using Op Amp.

    Please be patient with me and forgive my insistence regarding this, but why not. Some kind of filtering effect in the antenna?
  7. Miguel Lopez

    Amplitude Modulation using Op Amp.

    Well, this is what I finally get. I used 1V of negative bias at the gate of the JFET.
  8. Miguel Lopez

    Amplitude Modulation using Op Amp.

    This is what I'm talking about. The modulating signal is there and can be extracted using a simple diode. What is the reason why this method is not used?
  9. Miguel Lopez

    Amplitude Modulation using Op Amp.

    I'm agree, but my doubt still remains. During simulations, I've been able to extract the modulating signal from that kind of "added waves", using the same detector used for true AM. (The one present in the VEF206 radio)
  10. Miguel Lopez

    Amplitude Modulation using Op Amp.

    Transistors are not a problem. With the 1T311 it would work properly. Saddly the LM3046 is not an option due to availability. I was trying Op Amps in the EWB5.1 but none of which I have at hand can work at such frequencies, so I decided to test transistors. It is not for a transmitter, just to...
  11. Miguel Lopez

    Amplitude Modulation using Op Amp.

    I did it with the Gilbert cell !!!!. I used 2N2222 and 2N3904 transistors, but surely there should be any more suitable one for this purpose. I have some of them and they are in the EWB5.1 library. Two issues about this circuit. 1.-) I had to use 48V DC for the Gilbert cell (not exactly a...
  12. Miguel Lopez

    Amplitude Modulation using Op Amp.

    MW range approx. 500kHz to 1600kHz would be nice. Thank you very much for the Googling. And thank you for the words too. I didn't know so many words in English with such characteristics. :D :D :D
  13. Miguel Lopez

    Amplitude Modulation using Op Amp.

    . Generic. Hey..come on. I have never worked with a (word with "F", ending with "-ing") FET. I'm trying to learn and I'm asking for help. A diagram would be nice. Thanks
  14. Miguel Lopez

    Amplitude Modulation using Op Amp.

    I was trying this circuit on Electronics Workbench 5.1 sofware and althought it seems to modulate, positive halfcycle of the modulated signal are higher than negative ones. What am I doing wrong? I've been trying a Gilbert cell too but I have not reached positive results neither.
  15. Miguel Lopez

    VHF booster

    Yes, I did. Yesterday, when I got home, there was there the notification from the Post Office. I picked it up inmediately. Thank you very much
  16. Miguel Lopez

    VHF booster

    Then Eh??.... nop. :o I have just been reviewing the link you gave me in post #25. Very interesting, but as there is almost no design available with Soviet germaniums, I try to understand how the circuit works, with some help from all of you. I have to confess that radio frequencies...
  17. Miguel Lopez

    VHF booster

    Sorry, "dug up any design". I don't understand this expression. Please, be more conventional. Thanks :) No, I haven't received the parcel. But there is no motive to worry yet, as our mail system is not known by it fast response precisely. :D. It is still on time. Thank you very much for your...
  18. Miguel Lopez

    VHF booster

    Sorry to hear you're in a hospital. Hope you get better soon. There's no such components available to me here. I have only got those Soviet transistors at hand. Thank you both for your support.
  19. Miguel Lopez

    VHF booster

    Yes It is an NPN and I don't know the noise figure.
  20. Miguel Lopez

    VHF booster

    UCEmax = 12V UCBmax = 12V UEB = 2V Pmax = 150mW Ic = 50mA Hie = 30...180 Fmax = 300 MHz Plenty Nop. I'm just trying to see channels 2, 4, 6 of national TV which are seen very poorly in my town. Channel 7 in Cuba is "Cubavisión" broadcasted from Pinar del Río.
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