AM transmitter

Homemade $5 2-Channel AM transmitter

Although FM transmitters are a dime a dozen basically anywhere they sell anything (so you can pump your ipod/CDs whatever through any FM radio, like in your car). However, low power AM transmitters are a pain to find.

Some digging on the net revealed commercially available ones for around $50, but I wasn't ready to spend that much. I built my own, with about $10 in parts (if you had to buy it all new, I had all but $3 of it in junk bins). My final design was a jazzed-up chimera of about 3 similar designs. I could only find a handful of simple ones online.

I started with the version here at http://sci-toys.com/scitoys/scitoys/radio/am_transmitter.html . The basic idea is to run a signal through a crystal oscillator, which when output to an antenna, sends radio signals at a fixed frequency (in our AM band's case, 1.0 and 1.2 MHz).http://sci-toys.com/scitoys/scitoys/radio/xmitter_schematic.gif

Oscillators were purchased from Mouser.com for under $2 each. I added LED's, a switch, and 2 channels in case there's a radio station on one, or there's interference. I used the other half of my DPDT switch to control a single LED indicator.

http://www.agileguitarforum.com/uploader/files/1238906554-amtransmitter2.gif

However, there was a problem that caused the output from the antenna on one channel to influence the other one when both the antenna and ground are linked, essentially halving the power and causing both channels to always be transmitting. So, back to the drawing board, here's the final version that works like gangbusters:

http://www.agileguitarforum.com/uploader/files/1238907448-amtransmitter1.gif

Note: small transmitters must be kept very low power/small antenna, lest you step on the FCC's toes without a license. Be sure to check your state's laws.

Category:

Science & Technology

Tags:

• AM
• transmitter

[fancysnake1]

can you send me a diagram of this please?

[TheJerk1979]

Schematic link is in the description... Good luck!

[eirinoupoliwifi]

I want to create my amateur station.. what I need for this?

[SmashCOBamberg]

nice job!

[geliegelie]

can you send me the circuit diagram for this???

thanks a lot.,

[benjwgarner]

@Amishman35 I have a Grundig G6 Aviator Buzz Aldrin Edition and it tunes down to 150kHz. I have a long antenna in my backyard I hook it up to for better LW reception.

[180literkanon]

Very nice, can you send me the schematic ?.

Many thanks..

[skaterdudes2020]

nice

[radiorob1]

Cardboard box for an enclosure?

Hey, y not, when your using such low power.

Thanks for posting the schematic.

[Amishman35]

The frequency response of these transmitters can go above the range of human hearing...If you have a radio capable of receiving single sideband in the AM range (Grundig G5/G6 Aviator) , you can listen to radio stations below 300 kHz or so if you hook a long piece of wire to the input by tuning a bit away from the transmitting frequency. Since you have an older radio, you would get better quality than a newer radio would have because the bandwidth is bigger.