em field strength meter

[crusoe]

For this project we are designing the FSM for Bands II and III.
Band II 87.5-108MHz
Band III 174-230MHz
with frequency selector i need help with the analysis of the circuit and any good ideas.i've attached my cct
note. the resistor under the inductor is a variable,just forgot to correct it.the varactor is to provide the variable capacitance.
by varying the voltage across the variable resistance,we vary that across the varactor and hence the capacitance of the varactor.
i wish to display the output voltage on a dc voltmeter

 

[JimB]

The best analysis I can give of this circuit is that it does not stand a chance of doing anything useful.

Points to consider:

What is the purpose of the field strength meter, what is it going to measure?

What are the frequencies of bands 2 and 3?

How much selectivity do you expect from the single tuned circuit?

How are you going to vary the capacitance with the varactor?

What is the purpose of the variable resistor in the tuned circuit?

What sort of signal do you expect at the OUT terminal, how are you going to measure/display it?

When you have answers to these questions, you can start again with your design.

JimB

 

[audioguru]

The transistor part number is incomplete.
The battery's polarity is backwards for the PNP transistors.
The 10nF rectifier's filter capacitor is missing.
Un-needed 220k and 82k resistors are there.
T2 is saturated without a signal and will do nothing until a pretty high signal is received.
The output voltage is only 0.25V without a signal and will decrease with a signal.
Why use 3 transistors? The voltage gain is only 7.6 when it works.