Recent content by tazmania_kid

  1. tazmania_kid

    wireless transmitter

    Hi, anyone can explain to me the differences between the attached circuits in terms of construction and their performance? The reason is: understanding more on these circuits will help me proceed with better and more complicated tx circuits. Circuit 1...
  2. tazmania_kid

    wireless transmitter

    ok, I will try to make a coil myself and see what's the output :)
  3. tazmania_kid

    wireless transmitter

    As am new to circuit design, I thought, with coil value at 0.22uH, a 3-18pF capacitance change would in theory give you a frequency range of 80-196MHz. Too bad, it's not as easy as I think :(
  4. tazmania_kid

    wireless transmitter

    I didn't use an air core coil, instead I used a normal inductor which I bought from supplier. Is this possible?
  5. tazmania_kid

    wireless transmitter

    Hi, in regards to the circuit in the following link, I fix my inductor at 0.22uH then my variable cap at 3-18pF. So supposedly I should get a frequency of 88-108MHz right? But the tx frequency which I measured in the receiver is 50+MHz, y is this so?? I tried to use my radio as the receiver...
  6. tazmania_kid

    wireless transmitter

    help.....i couldn't get both 2N5109 and 2SC1324 in the market... :'(
  7. tazmania_kid

    wireless transmitter

    Can I use other transistor instead of 2N5109? In fact, what is the criteria that will affect your choice of transistor used?
  8. tazmania_kid

    wireless transmitter

    Hi Alun, am now trying on the 4 transistor circuit you've posted last time. But what is 7001? An NPN transistor of what series? Simply 7001?
  9. tazmania_kid

    wireless transmitter

    I have a Communication Service Monitor in my U and am planning to use this equipment as my receiver. In fact, it can also be a spectrum analyser, frequency counter... and so on. Regarding the tx power, again, am using another formula to manually calculate it. But frankly speaking, I am not sure...
  10. tazmania_kid

    wireless transmitter

    By using the indoor path loss formula, I plug in the values like transmitted power, received power (measured by the rx), distance between tx and rx, I can compute the path loss. Path Loss=PL(d0) + 10nlog(d/d0) where PL(d0)=10log(Pt/Pr) *I take d0, the reference distance, as 1m.
  11. tazmania_kid

    wireless transmitter

    I use back the original circuit. Before this, I used a function generator to replace the mic as the input but i am not sure whether this is correct? And at the output, I used an oscilloscope, the result is that the waveform looked weird. Until last night, I tried to use a mic and also the...
  12. tazmania_kid

    wireless transmitter

    Hi all, my transmitter can finally work! I tried to talk to the mic and use the radio as the receiver, as a result, I can hear my own voice from the radio! By the way, I tried to use a 1/4 wave antenna and also a very short length antenna, the result is that the radio can receive both signal...
  13. tazmania_kid

    wireless transmitter

    hi alun, thank you very much for your ideas. i will try to assembly it on a PCB as soon as possible and feedback to you ;)
  14. tazmania_kid

    wireless transmitter

    i stick to 88-108MHz as higher frequency will create more problems n more complicated circuit. as am new to circuit construction, i would rather choose a simpler one to begin with. so with this frequency, 1/4 wave is 0.69m.
  15. tazmania_kid

    wireless transmitter

    hi, i wonder whether i can reduce the antenna size by a fraction of the lambda? say (lambda / 8 ), (lambda/16)? what are the pros and cons of this length? cause if i were to use lambda/4, it will be a very big antenna in which it is not practical. other than a normal wire, what type of...
See more
Top