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Need help in 88-108MHz preamp circuit!!

Discussion in 'Electronic Projects Design/Ideas/Reviews' started by rahulan999, Aug 25, 2008.

  1. maxwelllll

    maxwelllll New Member

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    Thank you everyone in this topic it has helped me alot :D!!
     
  2. radiomate

    radiomate New Member

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    rahulan999 you shouldn't sell the bear's skin before you kill the bear :)
     
  3. radiomate

    radiomate New Member

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    What is your interest Maxwelllll? Working on any projects? Other than trying to derrive equations for Electromagnetics of course :D
     
  4. dave

    Dave New Member

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  5. rahulan999

    rahulan999 New Member

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    I think this guy will post pictures of his completed TEA5711 receiver tomorrow :D

    His current project is a 'High voltage Induction coil' !
     
    Last edited: Oct 9, 2008
  6. radiomate

    radiomate New Member

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    looks like we have made TEA5711 receivers "a la mode" (in fashion), everybody wants to make them :D

    High voltage induction coils, I love'em... They were first made by Nicola Tesla, if am not mistaken, an obscure electrical genious
     
  7. rahulan999

    rahulan999 New Member

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    Can u remember the communication range of a Tesla Coil based radio transmitter. How is the receiver is designed for that?
     
  8. radiomate

    radiomate New Member

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    I am a little rusty on the subject, but I think you are confusing this with the Hertzian transmitter, he used an ignition coil which produced sparks and transmitted the sparks to an open metal ring with 2 small balls a few feet away, he proved the existence of electromagnetic waves. I don't know if Tesla transmitted anything, he played around with induction coils of all sorts and some of them produced very large sparks all over the place :D Of course I can research the net and my books to sound more knowledgeable here, but I will not do that ;)
     
  9. rahulan999

    rahulan999 New Member

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    LM1036 also got in my pocket yesterday, very costly!
    I have ordered it from Mumbai and the supplier told that only 5 number is available and no chance to find anymore. So all the remaining pieces shipped to Bangalore as per my order;) and I picked only one because the IC was very HOT!

    Bought 10.7MHz filter(3pin) and discriminator(2pin). No one knows about the bandwidth whether its 150KHz or 450 like that. Its not written on the part also except the 10.7.
    They told its from something Moratto, Japan company. Check on net for datasheet. But I didn't find anything.

    455KHz Philips IFT is available for AM part. Is it necessary to use the same part no. mentioned on the datasheet?

    Apart from IFTs every obsolete parts for this project is obtained! I'm very happy :)
     
  10. radiomate

    radiomate New Member

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    Murata filters, not Morrato. You better know what the bandwidths are, u can't just use "whatever" in that circuit, and u shouldn't mix filters or your selectivity will be mashed potatoes ;)
    The IFTs don't have to be philips, but u have to respect the turns number as mentioned in the sheet. Like I said before, don't expect good selectivity on AM with just 2 IF tuned circuits!
     
    Last edited: Oct 15, 2008
  11. rahulan999

    rahulan999 New Member

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    Last edited: Oct 15, 2008
  12. radiomate

    radiomate New Member

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    150KHZ filters are good for this FM radio. Make sure the 2 filters are similar.

    Selectivity on AM will not be great with only 2 IF tuned circuits, but the sound quality will be nice with a wide bandwidth, and you will get a lot of birdies from adjacent stations beating with each other from lack of selectivity... a real symphony :D
     
    Last edited: Oct 15, 2008
  13. audioguru

    audioguru Well-Known Member Most Helpful Member

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    National Semi has the LM1036 in full production.
    Digikey has 367 in stock today for only $2.75US each (the cost of a cup of coffee in a restaurant).
    Newark has 246 in stock today for only $2.62US each.
     
  14. radiomate

    radiomate New Member

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    The price of a cup of coffee in the US maybe, not in France which is 2 to 3 times as much! ;)
     
    Last edited: Oct 15, 2008
  15. audioguru

    audioguru Well-Known Member Most Helpful Member

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    Because they drink wine in France, not coffee.

    Wait a minute. Bangalore is in India, not France.
     
  16. radiomate

    radiomate New Member

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    Un petit cafe a Paris coute a peu pres $5 a $6.. Ziss Minz ay small coffee in Paris costs about $5 to $6 ;) and I waz talkin aybout Paris :D

    By the way, Mouser Electronics doesn't carry the LM1036, and there is no NTE replacement for that chip.. Blouzers! :(
     
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  17. rahulan999

    rahulan999 New Member

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    Here, coffee is a very cheap item, so we not at all bother abt the price. Even in my house also coffee production plant is there. So if restaurants want to increase the price also nobody will mind :D

    My filters are marked as: SFA10.7MF
    and discriminators: 10.7FGF
    Can u differentiate it?

    Is that MKA293,294...numbers on datasheet represents IFT part no.?
    If I have to strictly follow the turns then, probably re-winding of IFT core is the only option. The highest gauge available for me is 49SWG. I think that specified .07mm may be something 52-54SWG ranges.
     
  18. radiomate

    radiomate New Member

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    It looks like the SFA10.7MF is a 50KHZ BW filter, which is too narrow for broadcast FM. Since you have internet, you can search the part for information. Search for muRata website also. I didn't get any results for "10.7FGF".
     
  19. radiomate

    radiomate New Member

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    I don't know about the MKA... again, do a search on the net. For the oscillator coil (L4), I would use a can with the red core, and for the 1st and 2nd IFT coils (L5 and L6), I'd use cans with the white and black cores respectively. You can canibalize these coils from a cheap AM radio. I wouldn't advise you to re-wind the coils, you don't need to re-invent gun powder man! As far as the windings, you can test resistances at the pins to decide which pin goes where. Larger windings will have more resistance and vice versa.
     
    Last edited: Oct 16, 2008
  20. rahulan999

    rahulan999 New Member

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    Yea, I have old 2in1 boards with IFTs on them. Also I already have a set of general purpose transistor radio IFTs.
    Once I will try to rewind for an experience, otherwise I will get a Philips part.
    50KHz filter will degrade the audio fidelity though the selectivity is at extreme level. The specified part no. is 455KHz BW with moderate selectivity and excellent audio quality.
    Here's a link:
    How to select a tuner for 88-108 MHz broadcast FM DX
     
    Last edited: Oct 16, 2008
  21. radiomate

    radiomate New Member

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    SFA10.7MF is 455KHZ BW? Way too wide!
     

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