In my research I found components on Kynix electronics site:http://www.kynix.com/Category/, and I followed the link to the schematic of the standard model: http://www.jameco.com/Jameco/workshop/JamecoFavorites/fmtransmitter.html. then I followed the link to another transmitter. After browsing a few pages of FAQ’s I came across this one from http://anarchy.translocal.jp/radio/micro/radioFAQ.html#q4. and I quote:
Q:How to increase the output power? A----This main unit is so sophisticatedly designed that you can boost the power only when you add a boosting circuit to it. The model circuit is here. I didn’t mention, but the transmitter (“1-3 watt”) has harmonic signals such as the double and tripple of the original frequency and you need a lowpath or bandpath filter between the transmitter and the antenna. When you connect this booster, such a filter is indispensable. Otherwise, you may have interference against television and radio.
And the circuit presented to me when I clicked the word “here” is the following:
Since my transmitter uses 5V, I plan to run this circuit with 5V instead of 12V. I do however have some quick questions:
The odds of me accessing the 2SC1970 transistor are low since I’m located in Canada. I do however have Pn2222, 2n3904 and Pn3563. The Pn3563 has a higher Ft (600Mhz) than the Pn2222 and 2n3904, so I’m looking for the best transistor to replace the one in the circuit.
Since I plan to transmit at the carrier frequency of 300 to 500Mhz, shouldn’t I make 33pF input capacitor lower?
Why in the circuit isn’t there a super high resistor value (such as 1M) from +12v to NPN’s base?
And wouldn’t the transistor blow up if enough signal gets injected into the base through the capacitor? and I say this because the choke is a short circuit at DC.
and why is 33pF, 100pF and 3.5 turns of wire made as a filter, is it supposed to be of a certain frequency to filter out the input before reaching the antenna? if so, what frequency?