Hi everybody! (This is the place where you would say hi Dr.nick, but you
don't)

I have two oscillators operating at the same frequency that I have salvaged
from an really old computer =). I am trying to build a transmitter and a
reciever around theese two oscillators. The transmitter should, as far as I
have understood, be fairly simple to construct using one of the oscillators,
but the reciever is giving me headaches =)

What I want is a simple reciever, not necessary audio, I only want to get a
current flowing when there is a signal. Would it be possible to construct a
simple one with the other oscillator?

I am fairly new to this sort of electronics and I would like easy
explanations or some url's that might interest me

I have many capacitators and resistors and transistors. I also have a few
coils with ferrite rods inside salvaged from old radio sets. The oscillators
are at 1.8Mhz each I think. (I have a few others that match too, but I can't
find them anywhere and if theese will work, then I won't bother looking), I
might try to use an old AM reciever and try to tune it to 1800khz, but I
would like to build it myself...

I have tried to search the newsgroup, but I had difficulities finding
anything that really helped so please don't flame that much.

Mvh Torbjørn, please excuse my English. You might understand that I'm not a
native speaker =)

try rec.antiques.radio+phono for urls

try rec.antiques.radio+phono for urls

Hejsan Torbjørn,
You are indeed quite correct in that the transmitter is easy. 50 turns on a
ferrite rod with a 250pf tuning cap and a low impedance coil (say, 10 turns)
from the oscillator module. Tune for maximum "smoke".

A simple diode ring mixer or in fact any old mixer will take an antenna and
oscillator to make a receiver. (such as
http://w1.859.telia.com/~u85920178/rx/quickrx.htm ).

You do have a problem. If the TX and RX are on exactly the same frequency
then the difference frequency is zero. So you will be receiving 0Hz
modulation from the TX. If you had a 800Hz frequency difference then you
would hear or be able to detect something. You need two oscillators of
different frequencies.

Finally, to operate at 1.8MHz may not be very nice for other users. Even a
few mW from a ferrite rod can give surprisingly large distances. I certainly
will not hear you in Stockholm, but you could have a few nasty surprises.
For example, many of the older chordless telephones used this sort of
frequency, but I think it may perhaps a little lower. Depending upon the
selectivity of these phones, you may quickly find yourself detected.

Another point is that it is a bit unsuitable to do tests in a radio amateur
band. Amateurs are proud of their licenses and even if they heard someone
"just playing" with low powers in their bands, then you would find yourself
reported. There are other bands you could experiment with where the users
are not so many or object to "intruders".

A suitable band would be light. An infra-red diode can have a standing DC
current fed into it, then you can couple your oscillator in there to
modulate the light. Any IR-LED receiver will receive that frequency, in fact
you can have your own legal HF band, right there in your home without fear
of annoying anyone. You can even connect IR-LEDs to the antenna socket of
communications receivers and get up to 50 - 100 metres range (line of
sight).

BR - Harry

"Torbjørn Viksand" wrote in message
...
Hi everybody! (This is the place where you would say hi Dr.nick, but you
don't)

I have two oscillators operating at the same frequency that I have
salvaged
from an really old computer =). I am trying to build a transmitter and a
reciever around theese two oscillators. The transmitter should, as far as
I
have understood, be fairly simple to construct using one of the
oscillators,
but the reciever is giving me headaches =)

What I want is a simple reciever, not necessary audio, I only want to get
a
current flowing when there is a signal. Would it be possible to construct
a
simple one with the other oscillator?

I am fairly new to this sort of electronics and I would like easy
explanations or some url's that might interest me

I have many capacitators and resistors and transistors. I also have a few
coils with ferrite rods inside salvaged from old radio sets. The
oscillators
are at 1.8Mhz each I think. (I have a few others that match too, but I
can't
find them anywhere and if theese will work, then I won't bother looking),
I
might try to use an old AM reciever and try to tune it to 1800khz, but I
would like to build it myself...

I have tried to search the newsgroup, but I had difficulities finding
anything that really helped so please don't flame that much.

Mvh Torbjørn, please excuse my English. You might understand that I'm not
a
native speaker =)

Hejsan Torbjørn,
You are indeed quite correct in that the transmitter is easy. 50 turns on a
ferrite rod with a 250pf tuning cap and a low impedance coil (say, 10 turns)
from the oscillator module. Tune for maximum "smoke".

A simple diode ring mixer or in fact any old mixer will take an antenna and
oscillator to make a receiver. (such as
http://w1.859.telia.com/~u85920178/rx/quickrx.htm ).

You do have a problem. If the TX and RX are on exactly the same frequency
then the difference frequency is zero. So you will be receiving 0Hz
modulation from the TX. If you had a 800Hz frequency difference then you
would hear or be able to detect something. You need two oscillators of
different frequencies.

Finally, to operate at 1.8MHz may not be very nice for other users. Even a
few mW from a ferrite rod can give surprisingly large distances. I certainly
will not hear you in Stockholm, but you could have a few nasty surprises.
For example, many of the older chordless telephones used this sort of
frequency, but I think it may perhaps a little lower. Depending upon the
selectivity of these phones, you may quickly find yourself detected.

Another point is that it is a bit unsuitable to do tests in a radio amateur
band. Amateurs are proud of their licenses and even if they heard someone
"just playing" with low powers in their bands, then you would find yourself
reported. There are other bands you could experiment with where the users
are not so many or object to "intruders".

A suitable band would be light. An infra-red diode can have a standing DC
current fed into it, then you can couple your oscillator in there to
modulate the light. Any IR-LED receiver will receive that frequency, in fact
you can have your own legal HF band, right there in your home without fear
of annoying anyone. You can even connect IR-LEDs to the antenna socket of
communications receivers and get up to 50 - 100 metres range (line of
sight).

BR - Harry

"Torbjørn Viksand" wrote in message
...
Hi everybody! (This is the place where you would say hi Dr.nick, but you
don't)

I have two oscillators operating at the same frequency that I have
salvaged
from an really old computer =). I am trying to build a transmitter and a
reciever around theese two oscillators. The transmitter should, as far as
I
have understood, be fairly simple to construct using one of the
oscillators,
but the reciever is giving me headaches =)

What I want is a simple reciever, not necessary audio, I only want to get
a
current flowing when there is a signal. Would it be possible to construct
a
simple one with the other oscillator?

I am fairly new to this sort of electronics and I would like easy
explanations or some url's that might interest me

I have many capacitators and resistors and transistors. I also have a few
coils with ferrite rods inside salvaged from old radio sets. The
oscillators
are at 1.8Mhz each I think. (I have a few others that match too, but I
can't
find them anywhere and if theese will work, then I won't bother looking),
I
might try to use an old AM reciever and try to tune it to 1800khz, but I
would like to build it myself...

I have tried to search the newsgroup, but I had difficulities finding
anything that really helped so please don't flame that much.

Mvh Torbjørn, please excuse my English. You might understand that I'm not
a
native speaker =)