AM Transmitter

[MarioMania]

Where can I find one pre-made??

This is just for fun, hooking it up to my PC & playing it though the Radio...

Eather Per-set at 1600 Khz or 1700 Khz

I'm not very good at buliding stuff..like in the $20 range..I'm on a tight budget

 

[LibertyNT]

no dice for an am already built going that low.
This would do better in the community radio forum.
You can get FM transmitters that cheap at wall-mart.

for AM the cheapest would be the SSTran at $100. but its a kit.

 

[kilokat7]

Talking House AM Transmitters

 

[pianoplayer88key]

I've seen older radio shack project kits with AM transmitter circuits for close to that price (maybe $30-$50, I'm not sure), but with the couple I've built, the signal would sink below the noise before I got across the room.

 

[stormy01]

no dice for an am already built going that low.
This would do better in the community radio forum.
You can get FM transmitters that cheap at wall-mart.

for AM the cheapest would be the SSTran at $100. but its a kit.

I highly recommend the SSTran AMT3000 - Beautiful sound, full frequency response and no hum! Even includes built-in variable compressor/ limiter. Sounds like some of the best broadcast stations and better than most of the radio of them! Your results may vary, of course. Depends on the audio source. There are other brands that are cheaper, but the transmission and audio frequency responnse, well, it stinks. You're not gonna save any money going cheap. FM may be the way to go if you're at some distance away from the transmitter for at night it could be a mess on any AM frequency.

 

[MarioMania]

I'm going to have it on like 1700AM...

I want like this http://www.instructables.com/id/Make-a-simple-AM-transmitter/

that's all

 

[stormy01]

I'm going to have it on like 1700AM...

I want like this http://www.instructables.com/id/Make-a-simple-AM-transmitter/

that's all

lol on that link above I read the post the guy claims 30 miles range - with that tiny module - riiiighttt! ok we will look for a crystal controlled circuit diagram that you can build yourself. I hope that some time and patience comes with the desire to build the TX, since it can be quite a challenge to get it to work, especially without some basic test equipment, like a DMM...I know, I've tried...

 

[FreddyE1977]

I've seen older radio shack project kits with AM transmitter circuits for close to that price (maybe $30-$50, I'm not sure), but with the couple I've built, the signal would sink below the noise before I got across the room.

I used to have one...and it worked great! But I don't think they have carried this item for at
least twenty years. (as the current punchline goes....just try and find a radio in there!)

 

[KeithE4]

I'm going to have it on like 1700AM...

I want like this http://www.instructables.com/id/Make-a-simple-AM-transmitter/

that's all

That's a hybrid clock oscillator. You'd need to (1) modulate it properly - good luck with what they suggest, (2) add a low-pass filter on the output since it puts out square waves, and (3) put an attenuator on the output as well since it puts out much more power than the 40-50 mW (100 mW input) allowed by the FCC. It puts out a 5 volt TTL signal (they think that it will work properly when powered from the audio source?!?!?), which is too much when delivered to a 50 ohm load.

They also do not come cut for whatever frequency you might want. A 1700 kHz device may or may not exist (I haven't looked at Digi-Key lately).

 

[FreddyE1977]

I have seen that set of instructions in multiple places, and in every case it says the transmitter
will broadcast at 1000 kHz. That appears to be a standard value for that off-the-shelf oscillator.

 

[KeithE4]

I have seen that set of instructions in multiple places, and in every case it says the transmitter
will broadcast at 1000 kHz. That appears to be a standard value for that off-the-shelf oscillator.

These oscillators are built for quite a few frequencies in the AM band, from 750 to 1664 kHz. Most are not on multiples of 10 kHz, however - such as 1544 kHz for T1 clocks.

In any case, the suggested circuit has design flaws one could drive a semi-truck through. I don't think such a "transmitter" would be legal under Part 15 due to the harmonics that are generated by the square-wave output.

 

[kenglish]

Back when I was a kid, there were things called "Phonograph Oscillators", that allowed you to "broadcast" your record player throughout your house. I used to buy them as a small module, which was potted in epoxy and had about 4 or 5 wires and a tuning "loop-stick" coming out of one side...they looked like they were molded in ice-cube trays. With one of these $5.00 modules, and a short piece of antenna wire (FCC said it had to be under ten feet long, transmission line and all!!), I broadcast WYAZ-AM to most of my neighborhood.

You might find something similar at a really old parts house.

 

[audioguy]

For a lower cost option, I highly recommend the SSTRAN AMT-3000 kit. It is fun to build, has great documentation, and will get you on the air with a good sounding AM signal. Depending on how much work you want to put into the antenna side of things, it will broadcast around your home and surrounding property with the included wire antenna, or you can add an external loading coil and it will cover your neighborhood. I have devised an indoor antenna setup that gives me a good signal on my entire block. It includes NRSC pre-emphasis (optional setting) and a built-in audio compressor that works well.

 

[trusty]

Back when I was a kid, there were things called "Phonograph Oscillators", that allowed you to "broadcast" your record player throughout your house. I used to buy them as a small module, which was potted in epoxy and had about 4 or 5 wires and a tuning "loop-stick" coming out of one side...they looked like they were molded in ice-cube trays. With one of these $5.00 modules, and a short piece of antenna wire (FCC said it had to be under ten feet long, transmission line and all!!), I broadcast WYAZ-AM to most of my neighborhood.

Back in the late '60s, I picked up a black ice-cube looking FM xmtr from Allied Radio (pre Radio Shack). It had 5 wires sticking out of it: 2 for a 9v battery, 2 for my signal, and 1 was the antenna about an inch long; the length of the wire determined the frequency. (I cut it too short and passed the open frequency I wanted, so I soldered some wire back to it and - voila! Then I cut it to the freq. I wanted. ;D)

I hooked up to the black cube and placed it on top of the house. I put on an LP record and drove around the neighborhood (I had to borrow a friend's portable radio as my car only had AM (Remember - it was the 60s. .) That thing blasted out a 1.5 - 2 mile radius! (Of course, I lived in Tampa at the time where the neighborhood was flat and line of sight means everything. )

(I had an AM xmtr, too, but we'll not talk about that (which means it wasn't all that great (I could monitor it in the yard, and it sounded like a bad phone line (kinda like an IBOC station :.))


I believed the black ice cube xmtr was the basis for Mr. Microphone, but not sure.

 

[BobOnTheJob]

Back when I was a kid, there were things called "Phonograph Oscillators", that allowed you to "broadcast" your record player throughout your house. I used to buy them as a small module, which was potted in epoxy and had about 4 or 5 wires and a tuning "loop-stick" coming out of one side...they looked like they were molded in ice-cube trays. With one of these $5.00 modules, and a short piece of antenna wire (FCC said it had to be under ten feet long, transmission line and all!!), I broadcast WYAZ-AM to most of my neighborhood.

Back in the late '60s, I picked up a black ice-cube looking FM xmtr from Allied Radio (pre Radio Shack). It had 5 wires sticking out of it: 2 for a 9v battery, 2 for my signal, and 1 was the antenna about an inch long; the length of the wire determined the frequency. (I cut it too short and passed the open frequency I wanted, so I soldered some wire back to it and - voila! Then I cut it to the freq. I wanted. ;D)

I hooked up to the black cube and placed it on top of the house. I put on an LP record and drove around the neighborhood (I had to borrow a friend's portable radio as my car only had AM (Remember - it was the 60s. .) That thing blasted out a 1.5 - 2 mile radius! (Of course, I lived in Tampa at the time where the neighborhood was flat and line of sight means everything. )

(I had an AM xmtr, too, but we'll not talk about that (which means it wasn't all that great (I could monitor it in the yard, and it sounded like a bad phone line (kinda like an IBOC station :.))


I believed the black ice cube xmtr was the basis for Mr. Microphone, but not sure.

I believe that long ago, the FCC assigned a 100 milliwatt power level to FM as well as AM. Needless to say, 100 milliwatts into a great antenna at a great height can carry for many miles. With an outdoor receive antenna on a clear frequency, 10 miles would be an easy accomplishment. They must have figured that out when the put the almost useless Part 15 FM figures into effect.