Does anyone have any plans for a small solid state transmitter? I would like to build one and mount it inside an old tape player. I have one I built from an old signal generator but I would like to simplify a little and have a one piece unit. I would be good to power it from the 9v allready in the tape player.
thanks
Tom

http://www.ramseyelectronics.com/cgi-bin/commerce.exe?preadd=action&key=AM1C

ramsey makes inexpensive kits. or you can get a more expensive one by sstran.

:Does anyone have any plans for a small solid state transmitter? I would like to build one and mount it inside an old tape player. I have one I built from an old signal generator but I would like to simplify a little and have a one piece unit. I would be good to power it from the 9v allready in the tape player.
:thanks
:Tom

Thanks Carlos, I would like to find one small enough to fit inside the cassett tape player. But I may give this a try if I can't find anything else.

Tom

:http://www.ramseyelectronics.com/cgi-bin/commerce.exe?preadd=action&key=AM1C
:
:ramsey makes inexpensive kits. or you can get a more expensive one by sstran.
:
::Does anyone have any plans for a small solid state transmitter? I would like to build one and mount it inside an old tape player. I have one I built from an old signal generator but I would like to simplify a little and have a one piece unit. I would be good to power it from the 9v allready in the tape player.
::thanks
::Tom

:Does anyone have any plans for a small solid state transmitter? I would like to build one and mount it inside an old tape player. I have one I built from an old signal generator but I would like to simplify a little and have a one piece unit. I would be good to power it from the 9v allready in the tape player.
:thanks
:Tom

http://sci-toys.com/scitoys/scitoys/radio/am_transmitter.html

:Does anyone have any plans for a small solid state transmitter?

Here's one I use for transmitting FM to my AM radio.
http://www.techlib.com/electronics/amxmit.htm and look for the Tunable Phono Oscillator at bottom of page.

Range is next to nothing but sound is impressively good. I use a small piece of wire hanging close to the radio's antenna. It uses a single transistor using a small osc can from a discarded transistor radio. It works using a 9V battery and fits on a 1 * 1.5" perfboard!

Of course, the Wenzel transmitter at the top of that link is much better but requires more parts. Not really necessary of the tape player/CD player sits besides or on top of the radio.

Hope this helps.

Thanks, I looked at it and I think that would do but where do I get the chokes? it calls for one of a 1 millihenry and one 10 millihenry and one 220 microhenry, would they be Radio shack parts?
Tom

::Does anyone have any plans for a small solid state transmitter?
:
:Here's one I use for transmitting FM to my AM radio.
:http://www.techlib.com/electronics/amxmit.htm and look for the Tunable Phono Oscillator at bottom of page.
:
:Range is next to nothing but sound is impressively good. I use a small piece of wire hanging close to the radio's antenna. It uses a single transistor using a small osc can from a discarded transistor radio. It works using a 9V battery and fits on a 1 * 1.5" perfboard!
:
:Of course, the Wenzel transmitter at the top of that link is much better but requires more parts. Not really necessary of the tape player/CD player sits besides or on top of the radio.
:
:Hope this helps.

:Thanks, I looked at it and I think that would do but where do I get the chokes? it calls for one of a 1 millihenry and one 10 millihenry and one 220 microhenry, would they be Radio shack parts?
:Tom

Hi Tom,

For the 1uH I used the black IF coil from a transistor radio (3rd IF) and the 220uH you can use the yellow one (for the others I used whatever close values I had on hand!). But you can make your own using a high value resistor (say 10 Mohms 1/8 Watt) and wind 50 turns of small gauge wire (say 30 gauge) on top of the resistor. Same for the antenna coil. You can probably find suitable coils at RS. You need low power miniature coils, no need for more than a few milliamps. The homemade works just fine in this case. Exact values aren't _that_ critical. The 10mH on the input can also be made the same way using more wire if you are on a budget (or use a small ferrite bead to wind the coil). Nothing is really critical as per value since it is meant to transmit very close to the radio's antenna post.

Picture of the tiny transmitter I use for my console radio (FM adapter and 78 phono). I also design my own fancy tube transmitters for around the house...

http://i267.photobucket.com/albums/ii307/m02_0193/100_1599.jpg

Old style tube transmitters I built (sold since):
http://i267.photobucket.com/albums/ii307/m02_0193/homebrew_2.jpg
http://i267.photobucket.com/albums/ii307/m02_0193/homebrew_1.jpg

Wow! they are realy nice base/inclosure ideas. I think I'll give it a try this weekend and see how it goes. If I end up making my own coils like you said, do I shunt the 10m ohm resistor accross the coil or just use it for a form? How many turns should I use for the input coil?
Thanks again for the help
Tom

::Thanks, I looked at it and I think that would do but where do I get the chokes? it calls for one of a 1 millihenry and one 10 millihenry and one 220 microhenry, would they be Radio shack parts?
::Tom
:
:Hi Tom,
:
:For the 1uH I used the black IF coil from a transistor radio (3rd IF) and the 220uH you can use the yellow one (for the others I used whatever close values I had on hand!). But you can make your own using a high value resistor (say 10 Mohms 1/8 Watt) and wind 50 turns of small gauge wire (say 30 gauge) on top of the resistor. Same for the antenna coil. You can probably find suitable coils at RS. You need low power miniature coils, no need for more than a few milliamps. The homemade works just fine in this case. Exact values aren't _that_ critical. The 10mH on the input can also be made the same way using more wire if you are on a budget (or use a small ferrite bead to wind the coil). Nothing is really critical as per value since it is meant to transmit very close to the radio's antenna post.
:
:Picture of the tiny transmitter I use for my console radio (FM adapter and 78 phono). I also design my own fancy tube transmitters for around the house...
:

:http://i267.photobucket.com/albums/ii307/m02_0193/100_1599.jpg
:
:Old style tube transmitters I built (sold since):
:http://i267.photobucket.com/albums/ii307/m02_0193/homebrew_2.jpg
:http://i267.photobucket.com/albums/ii307/m02_0193/homebrew_1.jpg
:

:Wow! they are realy nice base/inclosure ideas. I think I'll give it a try this weekend and see how it goes. If I end up making my own coils like you said, do I shunt the 10m ohm resistor accross the coil or just use it for a form? How many turns should I use for the input coil?
:Thanks again for the help
:Tom

Hi Tom,

Thanks.

Shunt the resistor with the coil.

Using a small ferrite core (the size of a 1/4W resitor or larger) is the only practical way when going beyond about 300uH. Use a ferrite salvaged from an old adjustable coil, from a computer power supply or similar donor. Without knowing exact core type hard to say exact number of turns. Try a couple hundreds turns. You may also experiment with a small steel bolt as a core. It's only a choke to keep RF away from the audio input.

Hi

Have you seen this?

http://sci-toys.com/scitoys/scitoys/radio/am_transmitter.html

Norm

::Wow! they are realy nice base/inclosure ideas. I think I'll give it a try this weekend and see how it goes. If I end up making my own coils like you said, do I shunt the 10m ohm resistor accross the coil or just use it for a form? How many turns should I use for the input coil?
::Thanks again for the help
::Tom
:
:
:Hi Tom,
:
:Thanks.
:
:Shunt the resistor with the coil.
:
:Using a small ferrite core (the size of a 1/4W resitor or larger) is the only practical way when going beyond about 300uH. Use a ferrite salvaged from an old adjustable coil, from a computer power supply or similar donor. Without knowing exact core type hard to say exact number of turns. Try a couple hundreds turns. You may also experiment with a small steel bolt as a core. It's only a choke to keep RF away from the audio input.

Norm,

:Hi

:
: Have you seen this?
:
:http://sci-toys.com/scitoys/scitoys/radio/am_transmitter.html
:
:Norm
:
:::Wow! they are realy nice base/inclosure ideas. I think I'll give it a try this weekend and see how it goes. If I end up making my own coils like you said, do I shunt the 10m ohm resistor accross the coil or just use it for a form? How many turns should I use for the input coil?
:::Thanks again for the help
:::Tom
::
::
::Hi Tom,
::
::Thanks.
::
::Shunt the resistor with the coil.
::
::Using a small ferrite core (the size of a 1/4W resitor or larger) is the only practical way when going beyond about 300uH. Use a ferrite salvaged from an old adjustable coil, from a computer power supply or similar donor. Without knowing exact core type hard to say exact number of turns. Try a couple hundreds turns. You may also experiment with a small steel bolt as a core. It's only a choke to keep RF away from the audio input.

Norm,
Yes I saw that one, but how well will it work? would you get good modulation? I was going to try to build the one that "Valid" posted a link to but must get my coils/chokes together. I have a hand full of chokes in a junk box that I'm tring to figure out there value. The way I'm doing this is to shunt them with a 100pf cap and checking that tank circut with a grid-dip meter then going to a website that I found to calulate the value of the coil.
easer way?

Tom
:
:
:
:
:
:
:
:
:
::Hi
:
:
:
:
::
:: Have you seen this?
::
::http://sci-toys.com/scitoys/scitoys/radio/am_transmitter.html
::
::Norm
::
::::Wow! they are realy nice base/inclosure ideas. I think I'll give it a try this weekend and see how it goes. If I end up making my own coils like you said, do I shunt the 10m ohm resistor accross the coil or just use it for a form? How many turns should I use for the input coil?
::::Thanks again for the help
::::Tom
:::
:::
:::Hi Tom,
:::
:::Thanks.
:::
:::Shunt the resistor with the coil.
:::
:::Using a small ferrite core (the size of a 1/4W resitor or larger) is the only practical way when going beyond about 300uH. Use a ferrite salvaged from an old adjustable coil, from a computer power supply or similar donor. Without knowing exact core type hard to say exact number of turns. Try a couple hundreds turns. You may also experiment with a small steel bolt as a core. It's only a choke to keep RF away from the audio input.

:easier way?

Yes, trial and error. Install them and test the circuit. Nothing critical, really.

The circuit I posted works very well and has adjustable frequency. But if you have a crystal whose frequency is close to a dead spot on the dial and an audio transformer in your junk box...