Problem with frequency adjusting

[Gurubhai]

Hi Friends,
I am starting a simple RF Transmitter project. I have basic knowledge of electronics. While simulating it on LTspice, I was unable to adjust the output frequency of this transmitter. I want at least 1wattage output from this circuit. I need help to fix this issues. Please advice me. I have attached a screen shot of LT Spice with Circuit Diagram.

 

[ronsimpson]

Please also post your spice file so we can play with it.

 

[Gurubhai]

LTSpice file is here.

 

[ronsimpson]

What are you using for the 2N5551?
I don't have a model for it.

Where did you get this schematic?
It is running at 1/2 frequency.

Please double check the value of L5! (decimal place)

 

[Gurubhai]

I have uploaded all npn transistor model for LTspice. Please download here. 2N5551 is used for final stage amplifier. I already tried many times changing the value of L5. Please try once again with this model.

 

[ronsimpson]

What you sent is the "picture" of a NPN transistor.
I need the other NPN file that gives the data from the data sheet.
Some how you have the numbers for the transistor and I don't.

 

[alec_t]

I'm curious as to why you have 3 different supply voltages?

 

[Willen]

I'm curious as to why you have 3 different supply voltages?

Once I had made a 'MOD-4 FM transmitter' designed by audioguru. I am seeing the 1st and 2nd stage is exactly as audioguru's MOD 4. Probably he is using his design as an oscillator and booster. Then used another RF amplifier for greater range.

If it is true then audioguru says (about MOD4) the oscillator has 7805 for frequency stability, RF booster has 9V because the transistor will burn at 12V. And at last the OP added a last stage is for maximum power from the amplifier with 12V standerd supply.

 

[Willen]

I have uploaded all npn transistor model for LTspice. Please download here. 2N5551 is used for final stage amplifier. I already tried many times changing the value of L5. Please try once again with this model.

Hi Gurubhai,
Ron said you just uploaded an picture file. Please go to C: Program files\LTC\lib\cmp folder and take a blue color file something like named: 'BJT' and upload it here.

 

[Gurubhai]

Please download this file, Unzip and install it. 2N5551 is exist here.

 

[Willen]

It is running at 1/2 frequency.

Hi Ron,
What is that mean? (Seems useful)

 

[audioguru]

The value of C4 is too high. When it is 4.7pF then the value of C3 can tune the oscillator frequency over the FM broadcast band.

 

[eTech]

Here is model for 2n5551

Place in schematic folder
Add include statement to your schematic:
.inc 2N5551.lib