mstechca
New Member
I was looking at a circuit on the web, and I wanted to adapt my superregen to it. It seems that the results are satisfactory, but at a low amplitude.
The circuit I looked at can be found at the following URL:
**broken link removed**
Basically, I took this circuit, and converted it into a common-base format, so that it can operate in VHF mode.
Here is how I modified the circuit.
The components I have omitted in my version are the PNP transistor, 0.1uF capacitor, and the output components (earphone and 10K).
The 100pF is grounded. (the tank is replaced by a short)
L1 and the 475pF is connected to the emitter. The components that were there are now omitted.
L2 and L1 are set to 0.1uF in my circuit.
RFC is 1uH in my circuit.
The variable capacitors in my circuit have no definite range because I'm looking for the best signal.
In my circuit:
I changed the 36K resistor to 18K.
I changed 560K resistor to 120K.
I omitted the grounded 120K so I can obtain maximum range.
When I added a 1.2pF capacitor between emitter and collector (feedback), I was able to pick up CHTV (air channel 11), but the volume was way too low.
Now here are the questions: (you can ignore my circuit.)
the 200pF trim capacitor in the original circuit must form part of the quench control. Is L2 the other component that adjusts this quench frequency or is there more to it?
The 475pF in the original circuit appears to select a station. Would I be better off to connect the capacitor between emitter and +ve instead of emitter and ground?
Is L1 the ONLY other component besides the 475pF that affects the incoming station frequency (carrier)?
Because I'm dealing with VHF/UHF, a PF makes a big difference. Is there any other component (including capacitors in transistors) that can directly affect the frequency? if so, how do they?
Sources tell me that the carrier frequency must be a multiple of the quench frequency. Also sources tell me that the quench frequency must be higher than the carrier frequency.
I want to be able to get the most gain out of this stage, and be able to use one trim capacitor to tune several dozen frequencies (or more).
The circuit I looked at can be found at the following URL:
**broken link removed**
Basically, I took this circuit, and converted it into a common-base format, so that it can operate in VHF mode.
Here is how I modified the circuit.
The components I have omitted in my version are the PNP transistor, 0.1uF capacitor, and the output components (earphone and 10K).
The 100pF is grounded. (the tank is replaced by a short)
L1 and the 475pF is connected to the emitter. The components that were there are now omitted.
L2 and L1 are set to 0.1uF in my circuit.
RFC is 1uH in my circuit.
The variable capacitors in my circuit have no definite range because I'm looking for the best signal.
In my circuit:
I changed the 36K resistor to 18K.
I changed 560K resistor to 120K.
I omitted the grounded 120K so I can obtain maximum range.
When I added a 1.2pF capacitor between emitter and collector (feedback), I was able to pick up CHTV (air channel 11), but the volume was way too low.
Now here are the questions: (you can ignore my circuit.)
the 200pF trim capacitor in the original circuit must form part of the quench control. Is L2 the other component that adjusts this quench frequency or is there more to it?
The 475pF in the original circuit appears to select a station. Would I be better off to connect the capacitor between emitter and +ve instead of emitter and ground?
Is L1 the ONLY other component besides the 475pF that affects the incoming station frequency (carrier)?
Because I'm dealing with VHF/UHF, a PF makes a big difference. Is there any other component (including capacitors in transistors) that can directly affect the frequency? if so, how do they?
Sources tell me that the carrier frequency must be a multiple of the quench frequency. Also sources tell me that the quench frequency must be higher than the carrier frequency.
I want to be able to get the most gain out of this stage, and be able to use one trim capacitor to tune several dozen frequencies (or more).