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    Making PCBs with magazine's paper

    Hey Dido You have very good equipment for playing with chemical..... ;) For me, I only use plastic box to etch my PCB at home.... :-[ At office, there is a tank of etching solution, but it is slow and dirty........
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    Making PCBs with magazine's paper

    I hear someone using concentrated Sulphuric Acid to have fast etching of PCB . Personally I haven't try because it is very corrosive.... very danger for diy..... so I prefer to wait for 15 minutes :P
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    remote control using radio freq

    You are welcome. I just found the site yesterday where some of the circuits inside are useful to me too ;D
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    Notch Filters and Noise Cancellers

    You can also check this link in case you are sure the grounding is ok. http://members.shaw.ca/roma/nine.html
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    remote control using radio freq

    Check this link for some useful circuit http://members.shaw.ca/roma/seventeen.html
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    Notch Filters and Noise Cancellers

    hmmm...... such hum may cause by poor DC grounding or the tuner circuit problem. Can't give you much suggestion by now unless we have a chance to look at the circuit or PCB baord.
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    How do I solder SMD components with a regular iron

    It is a nice idea but the copper wire will stick with solder and may mess up your work...... My experience is to use sharp solder iron (25W is fine) + thin solder (0.6mm) + tweezer + solder paste , then everything will be nice. But somehow beware of the solder stick to adjacent components' pads.
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    How do I solder SMD components with a regular iron

    I think it may be an 0402 size component. The soldering method is the same as other size but suggested to use a sharper solder iron to do so.
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    remote control using radio freq

    hmm......... you can use tone detector IC (LM567 ) after reciever for such application which will lower the complexity of building the comparator. I haven't build circuits with this IC but I do think it may fit your needs.
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    Nice Big Collection Of Electronic Software!

    Very nice site!! Good!!! May try some later for fun :P
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    Parts from stuff

    Try to get more solder on the pads and use solder iron to melt. After a several seconds, you can easily pull components out. That is what I do in the factory.
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    Free sample chips!

    As I am in Hong Kong, I think most of the IC manufacturers will forward the sample order to the distributors in Hong Kong......... and I do think most of them are not willing to send samples especially we are for our own usage.... :-\ I haven't give an order yet.....hmm....... may be I should...
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    AM/FM Radio Tuning methods

    Thanks for reply. I can tell you that I am currently working on digital tuning system, that is, a PLL+VCO. However, it is quite different from that of manual tuning using capacitor, esp. matching RF coil part. I know that for radio sensitivity, mostly it related to circuit layout and component...
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    remote control using radio freq

    higher frequency will have more interference esp. 2.4GHz band...... like microwave oven, DECT phone, wireless lan, Bluetooth etc. For 433MHz, I think if you are in UK, the most problem will be caused by the TETRA (police RF communication ?? not sure, it is at 426MHz). You have to build a narrow...
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    Protel DXP PCB Question

    There is no easy way to place components, it really depends upon experience and some restrictions towards mechanical and/or electrical issues. I will use alignment tools in the CAD to make the components placement looks more tidy......... that is what I do...
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    remote control using radio freq

    2.4GHz ISM band is a bit difficult for me esp. to build transmitter, because it involves a lot of matching problem. Although you can build using simple LC+transistor circuit but if you don't have a spectrum analyzer or signal generator, it will not an easy job. For me, I will start with...
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    AM/FM Radio Tuning methods

    Would like to know if there are any good websites about AM/FM tuning methods......? Although I have worked on this stuff for quite a few years, I still keep on trial-and-error methods for fine tuning..... And what are the sensitivities standard for AM/FM radio?? (I have several info but...
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    Protel DXP PCB Question

    It depends how complex your PCB is and the components you are choosing (through hole or SMT)..... For my experience, try to put connected components closed together and try to route tracks through gaps of components (except IC pins).... But don't expect the auto-route function can give you...
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    remote control using radio freq

    Think of the followings: 1. Transmit distance 2. Transmit frequency 3. Transmit modulation (AM, FM, etc) 4. Bandwidth/ data rate of the commands Hope these give you some insight... ;D
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    call timer for mobile phones

    if you have a chance in access a spectrum analyzer, you will noticed that the cell phone isn't transmit continuously. I suggested if you want to use the RF signal as the sourcce, you can use RF scottkey diode to pick up the RF signal, and sample its presence in a certain period of time, say for...
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