Increasing transmitter power .

Thread Starter

Antsy electron

Joined Dec 27, 2022
69
I made a 10 MHz xtal transmitter, it transmits perfectly at 10 Mhz and weaker at the harmonics, it is composed of an oscillator, audio stage and RF out . Thing is it only reaches 2 meters . How can its power be increased, does voltage do it ?
 

Halfpint786

Joined Feb 19, 2018
109
Holy crap man, what a choice of frequency! I suggest you find a different crystal quickly. Do you have any idea how big the FCC fines are? 5 to 6 digits minimum. Get off WWV's frequency before a vehicle covered in antennas shows up at your door!
 

Halfpint786

Joined Feb 19, 2018
109
WWV is more than just a time station. For those who do not have a Caesium clock, WWV serves as a fairly accurate reference for aligning things like frequency counters. I zero-beat against WWV all the time to ensure my counter is accurate. Imagine how many things can get screwed up if someone zero-beats to your signal at 10.0021248652 MHz when aligning their equipment.

I don't think you understand how radio propagation works. At 10MHz, your signal will hit the ionosphere and come back down. If you happen to get your antenna right, just a mW or two of power might be heard around the country. The National Institute of Standards and Time, along with the FCC, will be out to get you. Good luck.
 

Halfpint786

Joined Feb 19, 2018
109
You really don't need a crystal anyhow. If you just want to send music/voice to a radio, you could do that with a whole variety of simple LC oscillator circuits. There are FM bug schematics out there that will put your audio onto the FM broadcast band. There are AM transmitters that can do the same.

Go search for the Bipolar Transistor Cookbook over at Nuts and Volts, download all 7 parts, then open part 5, go down to the modulation section and take a look at that schematic. That circuit will work every time you build it, even if the parts are not exactly the same. I made one for MedFER (AM broadcast band) by rewinding an IF can and had a lot of fun with it. You can run 100mW with a 3m antenna on the MedFER band with no license.
2023-01-30 14_00_06-bipolar_transistor_cookbook_part_5.pdf - Adobe Acrobat Pro.png
 

Thread Starter

Antsy electron

Joined Dec 27, 2022
69
WWV is more than just a time station. For those who do not have a Caesium clock, WWV serves as a fairly accurate reference for aligning things like frequency counters. I zero-beat against WWV all the time to ensure my counter is accurate. Imagine how many things can get screwed up if someone zero-beats to your signal at 10.0021248652 MHz when aligning their equipment.

I don't think you understand how radio propagation works. At 10MHz, your signal will hit the ionosphere and come back down. If you happen to get your antenna right, just a mW or two of power might be heard around the country. The National Institute of Standards and Time, along with the FCC, will be out to get you. Good luck.
Thanks a lot man , I will .
 

Janis59

Joined Aug 21, 2017
1,822
With just altering the voltage You make the sh** even deeper because the output impedance aproximately is R=1/40/ic. Thus at Ic=1mA that would give 25 ohms. You need the 50 Ohms.... Do You still have any questions? However, probably I may guess what is wrong with Your circuit. Just try to adjust better Your output Pi-filter.
 
Last edited:
Top