| Author | Message | ||
     Zprag Unregistered guest |
Hi i built the radio transmitter with all the same parts as you except i used alligator clips are wire instead of a circuit board. when i tune the reciever to 1000 khz and turn on my cd player i get a high pitch whine. I have a mono audio plug hooked into the cd player. I cant figure out whats wrong. Thanks Zach | ||
| Simon Quellen Field (Sfield) Senior Member Username: Sfield Post Number: 411 Registered: 12-2004 |
Does the whine go away when you remove power from the oscillator? Does the whine go away when you turn off the CD player? With the CD player and the oscillator turned off, you should hear static on the radio. When you then power up the oscillator without the CD player, you should hear the static get quiet. Some experiments to try: 1. With the oscillator off, turn on the CD player. The player may not be well shielded, and it may be transmitting a whine at 1 Mhz all by itself. If this is true, use a different sound source. 2. The CD player might be putting DC out to the headphones. Try putting a 1 microfarad capacitor in series with the input jack to eliminate any DC from getting through. Or try a different sound source. 3. The CD player might expect 32 ohm headphones or 16 ohm headphones instead of 8 ohms. If this is the case, try a different sound source. 4. I assume you have already tried playing with the volume levels on the CD player. If not, this would be a good time to do so. | ||
| zprag Unregistered guest |
The cd player was faulty. Im using an mp3 player now. The static goes quiet when oscillator is plugged in however still no sound. I played with volume levels still nothing. Does the fact that im using a mono stero plug mean anything or that the alligator clips are hooked to bare wire? Thanks Zach | ||
| Simon Quellen Field (Sfield) Senior Member Username: Sfield Post Number: 412 Registered: 12-2004 |
Check item #3 above. Also check to make sure the transformer is the right way around. You can switch it around as a test without hurting anything. The clips should be connected to bare wire (so they make a connection, clipping them to insulated wire would not make an electrical connection). Make sure the clips do not touch the metal case of the oscillator. Start with the transmitter and the receiver very close together. You can play with the volume controls on the receiver as well as the MP3 player. You can also try a cheap transistor radio instead of the MP3 player -- the cheap radios have mono jacks and almost always use 8 ohm headphones. |
