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    RC-(remote controlled) Car

    Does anyone knows dbm to mW conversion . the output power of The Transmitter is +10 dbM , how much will be it in mWatts .  ???
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    RC-(remote controlled) Car

    hello again , after a long time i am back , and this time i have found two new crystal controlled IC's that suffice my needs , MC2833 FM Transmitter and MC13136/35 and MC3362 FM Reciever IC's . These IC's are crystal controlled and i think they will be fine for my Radio controlled Car. But Will...
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    Parallel Port LED Dimmer.

    okay 33 pins are NC which are not connected so this leaves only 67 , out of which 16 are output to led which leaves 51 pins out of which 16 are for DIN and DOUT which leaves 35 pins and out of which only 2 pins are for register select for brightness control and DCLK , the only question i want to...
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    Parallel Port LED Dimmer.

    please can anyone help me on this subject
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    my radio is changing stations by itself!

    you might have varactors in the opposite direction as in my circuit.
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    50Hz when you touch Oscilloscope probe

    no i think it is somewhat your pulse rate .  ;D , like a ecg machine
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    Parallel Port LED Dimmer.

    I am Planning to build a parallel port led dimmer using ti's TLC5904 which uses 8 data inputs for adjusting the brightness or in other words current . you can control upto 15 LED's using this IC . I know how to interface the parallel port But there is some complication in this is , i don't...
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    RC-(remote controlled) Car

    But if you can implement AFC on the reciever side , why not in the transmitter side . But i think for my project that radio is sufficient ,
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    RC-(remote controlled) Car

    yeah i get it , this means the TX-500 will be rock solid transmitter if it is PLL Controlled . and one more thing the IC i have for the radio is a KA22425 and also it's equivalent CXA1618M , well the PDf is attached .  i know it is not PLL Controlled but why it is stable . i also used it to...
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    RC-(remote controlled) Car

    Hello again , i have a question how can i implement a crystal oscillator i found on the net in my modulator and replace the LC circuit  . the desciption and circuits of fundamental crystal oscillators and overtone crystals are given here http://hem.passagen.se/communication/txo.html One more...
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    RC-(remote controlled) Car

    Well The PCb Layouts for the power meter are made , now its time to prepare the board and practically test it . will update soon
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    PCB photofabrication

    Still i must say that Toner Transfer method is the best , i have printed an adaptor which is 7 to 10 mil and with perfect results . Just using simple glossy paper , which just cost's nothing compared to the photographic method and an iron. i have also tried the Photoresist method  but with not...
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    RC-(remote controlled) Car

    Well here is the schematic of the Power meter . i am feeling a little sleepy , will make assemble and develop the board for the oscillator and power meter , until then astalavista baby !!!
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    RC-(remote controlled) Car

    WHy not use a step up boost voltage regulator , like the ti's UC2577 , but it has a bulky circuit and high amperage . i think a small step up boost voltage regulator with 0.5 A and 12 V regulation voltage would be ok . But then again why bother , and just connect the 12 Volt battery pack...
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    RC-(remote controlled) Car

    So if i remove it , it will be ok for DTMF and if i remove it . it will work for voice. now i will post the power meter shortly. one more thing i am putting a 12V voltage regulator for both the VHF power meter and as well as the VHF Amplifer. is it ok.
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    RC-(remote controlled) Car

    Hello i am back with some modifications . here is a v1.1 of the oscillator TX-500 . i have added a 1nF capacitor for better stability . the rest is that varactor diodes have changed their posistion. Now i will build the power meter... Asap
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    RC-(remote controlled) Car

    But in the original schematic it is with this configration , take  a look here .. i am a little confused here  ??? and look at the power meter also ... really confused , don't know what to do , then just to experiment.  ??? I think the varactor are in the right direction because it is...
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    RC-(remote controlled) Car

    well i have completed the Oscillator section and here are the PCb board layouts and schematics . For your question that i will have crowded bands , the answer is that 105mhz FM Band has no radio station , so it will work for me . and keep in mind this is only a educational project. SO NO...
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    RC-(remote controlled) Car

    I will be using a 12V battery pack. and also be using MPSH10 VHF/UHF Transistor , and what do you know , it has really low frequency drift.  i will also be making a board layout with ground plane. so well this all will reduce frequency drift , but using a PLL would be really nice to reduce...
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    RC-(remote controlled) Car

    Housing it in a mettalic case will reduce the frequency drifts. and the supply voltage is also regulated with a 7805 regulator. but the thing that will have affect is only temprature.
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