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Discussion in 'General Electronics Discussion' started by Miguel Lopez, Aug 24, 2012.

  1. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

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    May 8, 2012
    Give me some time to see what I can work up. Typically, I like to Spice a circuit before I post it but I may not be able to do that with this transistor.
     
  2. davenn

    davenn Moderator

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    Sep 5, 2009
    this application should really be using an MMIC like a MAR1. extremely low component count, VERY wide band .... plenty of gain and are available world wide dirt cheap!!

    here's a link to one using a MAV11 ( there's several sets of MMIC devices)
    http://www.qsl.net/vk3jeg/wideband.html

    cheers from dave in his hospital bed :)
     
  3. Miguel Lopez

    Miguel Lopez

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    Jan 25, 2012
    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.
     
  4. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

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    May 8, 2012
  5. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

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    May 8, 2012
    Miguel, I'm heading out to my watering hole. In the interim here's some good reading for you. Google is your friend. Do some leg work while I'm kick'n back.

    http://www.google.com/search?q=germ...v&sa=X&ei=-149ULmwDI389gTRloHwAw&ved=0CCwQsAQ

    This one is a very good read and and reminds me why I initially rejected transistors in those days. I played and had fun with them but I never took them seriously until Silicon came along. Trouble shooting Germanium circuits was a nightmare too!

    http://www.wylie.org.uk/technology/semics/GEC/radio/article.htm

    http://semiconductormuseum.com/MuseumStore/MuseumStore_Index.htm
     
  6. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

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    Miguel, have you dug up any designs?
     
  7. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Did you get those jfets I sent to you?

    They may be better suited to this application.
     
  8. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

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    Steve, did you do that? I wonder if they'll get past security? What FETs did you send him? Especially, since I'd want to just stick them in an envelope. I have about 500 MPF102's with Motorola factory markings (purchased mil surplus in1979) but I didn't think they'd get to Miguel. Uh... that's two or three, not 500. :D

    Chris
     
  9. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    We have no restrictions on what we can send to Cuba (outside such things which are not permitted in the mail -- firearms, ammunition, dangerous goods, certain biological materials, etc.)

    I also verified (as far as I could) that the components were not originally sourced from locations with a form of embargo.

    *snap* I think some were MPF102's (or similar). However much of what I have is surface mount. and Miguel doesn't have much experience working with it.
     
    Last edited: Sep 2, 2012
  10. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

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    Ha, I was referring to Cuban security.

    Chris
     
  11. Miguel Lopez

    Miguel Lopez

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    Jan 25, 2012
    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 kindness.
     
  12. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

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    Dig up: (1) To find, locate, discover, (2) To find or locate by searching, sifting and separating the inapplicable.

    Dug up: Past tense of "dig up".

    Example: Steve, near starvation, was wandering around in the Outback until he dug up some edible tuck. :D

    Chris
     
  13. Miguel Lopez

    Miguel Lopez

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    Jan 25, 2012
    Then

    Eh??.... nop. :eek:

    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 have always been beyond my complete understanding. I work good enough in the audio range, but with high frequencies...... I guess I missed that part in the school :D
     
  14. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

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    Since Dave sent you some MPF102's here's some links of tuned RF amplifier designs. You would have to recalculate the resonant circuits for the frequency your using.

    http://radiofrequencyamplifier.blogspot.com/2012/02/6m-rf-preamp-using-mpf102.html
    http://radiofrequencyamplifier.blogspot.com/2012_02_01_archive.html

    Attached is the Motorola PDF. It includes a broad band amplifier design.... Oops! I can't attach it because it's too large. Google the PDF but not all of them contain the broad band amp. My Motorola PFD does.

    Chris
     
  15. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

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    May 8, 2012
  16. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

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    May 8, 2012
    They didn't coin it the "Iron Curtain" for no reason. ;)

    RF design is a field unto itself. If you want a fascinating topic, read up on "Transmission Line Theory & Design" in the ITT "Reference Manual For Radio Engineers". It's the RF Bible!

    By the way, the broadband amp in the PDF uses a 50Ω input Z. TV transmission line (Coax) is 75Ω. This is not a severe mismatch though. To provide 75Ω input/output you'll have to calculate that too.

    Chris
     
  17. Miguel Lopez

    Miguel Lopez

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    Jan 25, 2012
    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
     

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