zachtheterrible said:
How in god's name did you get a VHF circuit to work on a breadboard!!?!? Low frequency?
No, high frequency. Somewhere around the 220Mhz range. :wink:
and how in god's name did I do it?
I take a common transmitter circuit and modify it. and the transistor I used is a PN3563 NPN which has an Ft of 600Mhz!
Range is directly proportional to the transmitted signal strength
....
a) Increase the power output of the transmitter.
That makes sense. and that is what I did when I replaced the resistor with a large value inductor as described above. The only competition I have is the battery :lol: because as the battery weakens, so does the power, so does the range.
b) Increase the gain of the transmitting aerial (by making it directional).
I want to avoid an antenna as much as possible. But I must say, the distance is exceptional considering my antenna is about 1 1/2 feet long, and I'm using less-than-perfect batteries.
c) Increase the sensitivity of the receiver, at VHF frequencies this is limited by the noise factor of the RF preamp used.
Noise is low, and my sensitivity is good since I can pick up TV signals.
My superregen detector also uses a PN3563.
If you want to reduce the current consumtion you have to either increase the efficiency of the transmitter
I guess efficency is what I will have to work on.
I think he used 1pF capacitors and the stray capacitance of the wiring provided the rest of the required capacitance.
LMAO :lol:
transmitter's stray capacitance doesn't matter now. In fact, higher capacitance wouldn't even make much difference in my circuit unless it is connected to the RF oscillator.
The transmitter doesn't transmit very far because VHF has a difficult job travelling through the series inductance of the wiring.
I tried replacing the series inductance with a 0.1uH inductor, and I get no signal
I still think my house is bad for reception.