How to convert frequencies

Hello,

I'm a complete electronics novice but would like to get involved at a basic level. As a project I'd like to receive a radio frequency, convert it, and then transmit it on to my radio receiver. Sort of like a proxy I suppose.

After some basic research I think I need the following:

Antennae to receive RF
RF mixer to filter the frequencies
Oscillator to pass in the desired frequency to the RF mixer
Low pass filter to filter out the unwanted frequencies
Amplifier
Transmitter

And some sort of circuit board to put it all together. I'm curious how home brew electronics work with regards to circuit boards. I'd like the device to be as compact as possible, but don't mind if the prototype is a huge monstrosity.

I'll have a look around a bit further myself, but wondered if you had any pointers that might save me time and sanity.

Cheers,

Gordy

 

[George Herold]

On Apr 16, 5:19 am, gordon.is.a.mo...@gmail.com wrote:

Hello,

I'm a complete electronics novice but would like to get involved at a basic level. As a project I'd like to receive a radio frequency, convert it, and then transmit it on to my radio receiver. Sort of like a proxy I suppose..

After some basic research I think I need the following:

Antennae to receive RF
RF mixer to filter the frequencies
Oscillator to pass in the desired frequency to the RF mixer
Low pass filter to filter out the unwanted frequencies
Amplifier
Transmitter

And some sort of circuit board to put it all together. I'm curious how home brew electronics work with regards to circuit boards. I'd like the device to be as compact as possible, but don't mind if the prototype is a huge monstrosity.

I'll have a look around a bit further myself, but wondered if you had any pointers that might save me time and sanity.

Cheers,

Gordy

Hmm, maybe just start with building a radio reciever. I'm sure there
are lots of designs on the web. A little AM reciever is pretty easy.
(Read low frequency). If you continue interest then find out if there
is a local HAM group in your area. There may be some pepole there
that can help. Oh, and pick up a copy of the ARRL handbook. Lots of
practical advice and circuits.

George H.

 

[Michael Black]

On Mon, 16 Apr 2012, gordon.is.a.moron@gmail.com wrote:

Hello,

I'm a complete electronics novice but would like to get involved at a
basic level. As a project I'd like to receive a radio frequency, convert
it, and then transmit it on to my radio receiver. Sort of like a proxy I
suppose.

Then start with the basics and give the details. Why not just buy a

receiver that tunes the frequency? What is the frequency? Is this for
the sake of building something, or to get some end results?

Michael

 

[Tim Wescott]

On Mon, 16 Apr 2012 02:19:57 -0700, gordon.is.a.moron wrote:

Hello,

I'm a complete electronics novice but would like to get involved at a
basic level. As a project I'd like to receive a radio frequency, convert
it, and then transmit it on to my radio receiver. Sort of like a proxy I
suppose.

Essential terminology:

You want to receive a radio _signal_ at a particular _frequency_, shift
the frequency, and retransmit.

After some basic research I think I need the following:

Antennae to receive RF
RF mixer to filter the frequencies

RF mixers shift signal frequencies. Filters filter signals (generally
within some band of frequencies)

Oscillator to pass in the desired frequency to the RF mixer

Oscillator to pass the desired frequency _difference_ to the mixer.

Low pass filter to filter out the unwanted frequencies

Or some sort of filter -- probably bandpass.

Amplifier, Transmitter

An amplifier is part of a transmitter -- stick an antenna on the end of
yours, and you're done.

If you're broadcasting within your house, then just sticking an antenna
on the end of your post-mixer filter may well be enough.

And some sort of circuit board to put it all together. I'm curious how
home brew electronics work with regards to circuit boards. I'd like the
device to be as compact as possible, but don't mind if the prototype is
a huge monstrosity.

AM? FM? Regular broadcast frequencies or something more out of the way,
like FRS, CB, or shortwave?

I'll have a look around a bit further myself, but wondered if you had
any pointers that might save me time and sanity.

Buy a receiver that works on the band that you want -- one from Goodwill
or a rummage sale should be fine. Buy a transmitter kit that works on
the band that you want. Feed audio from the receiver to the
transmitter. Stand back and enjoy (well, stand back and debug).

Then, when you get that working, you may know enough to go on to some
other step.

Ramsey Electronics has kits for you. There is, to my knowledge, no real
Gold Standard in electronics kits since the demise of Heathkit -- but
Ramsey sells some pretty good brass.

--
My liberal friends think I'm a conservative kook.
My conservative friends think I'm a liberal kook.
Why am I not happy that they have found common ground?

Tim Wescott, Communications, Control, Circuits & Software
http://www.wescottdesign.com

 

[Tim Wescott]

On Mon, 16 Apr 2012 02:19:57 -0700, gordon.is.a.moron wrote:

Hello,

I'm a complete electronics novice but would like to get involved at a
basic level. As a project I'd like to receive a radio frequency, convert
it, and then transmit it on to my radio receiver. Sort of like a proxy I
suppose.

After some basic research I think I need the following:

Antennae to receive RF
RF mixer to filter the frequencies
Oscillator to pass in the desired frequency to the RF mixer Low pass
filter to filter out the unwanted frequencies Amplifier
Transmitter

And some sort of circuit board to put it all together. I'm curious how
home brew electronics work with regards to circuit boards. I'd like the
device to be as compact as possible, but don't mind if the prototype is
a huge monstrosity.

I'll have a look around a bit further myself, but wondered if you had
any pointers that might save me time and sanity.

Cheers,

Gordy

I didn't want this answer to get lost in my other reply: what you're
thinking of building is a repeater or a translator (depending on who you
ask). If you want to look for a kit or on-line schematics, those are the
search terms to use.

--
My liberal friends think I'm a conservative kook.
My conservative friends think I'm a liberal kook.
Why am I not happy that they have found common ground?

Tim Wescott, Communications, Control, Circuits & Software
http://www.wescottdesign.com

 

[Bob Myers]

On Monday, April 16, 2012 3:19:57 AM UTC-6, gordon.i...@gmail.com wrote:

Hello,

I'm a complete electronics novice but would like to get involved at a basic level. As a project I'd like to receive a radio frequency, convert it, and then transmit it on to my radio receiver. Sort of like a proxy I suppose..

After some basic research I think I need the following:

Antennae to receive RF
RF mixer to filter the frequencies
Oscillator to pass in the desired frequency to the RF mixer
Low pass filter to filter out the unwanted frequencies
Amplifier
Transmitter

And some sort of circuit board to put it all together. I'm curious how home brew electronics work with regards to circuit boards. I'd like the device to be as compact as possible, but don't mind if the prototype is a huge monstrosity.

I'll have a look around a bit further myself, but wondered if you had any pointers that might save me time and sanity.

Cheers,

Gordy

I would agree with the suggestion that you start looking for a basic receiver design to start with - but would say that even that's a bit of a stretch if you are a "complete electronics novice."

What you are trying to do IS basically what's called a "superheterodyne" receiver, which describes the vast majority of radio receivers out there today anyway. The hallmark of a "superhet" design is that it converts all incoming frequencies to a common "intermediate frequency" which is then amplified and demodulated. Getting a copy of a good basic text on radio - the ARRL Radio Amateur's Handbook" might be a good place to start - would be a great start in the right direction. (It's really too bad that the good ol' classic Heathkits are no longer available. However, there are still some basic receiver kits available to get started with, like:

http://www.amazon.com/Ramsey-SR2C-Shortwave-Receiver-Kit/dp/B0002NRL9I

http://www.tentec.com/products/9%252dBand-SW-Receiver.html (not a superhet, but could be fun))

One minor gotcha in building a superhet is that this type of receiver requires an adjustment process ("alignment") to get everything working properly together - it's not impossibly difficult, but again may be a bit much for the real novice to pull off, especially without some test equipment.

Bob M.

 

[John Larkin]

On Mon, 16 Apr 2012 02:19:57 -0700 (PDT), gordon.is.a.moron@gmail.com
wrote:

Hello,

I'm a complete electronics novice but would like to get involved at a basic level. As a project I'd like to receive a radio frequency, convert it, and then transmit it on to my radio receiver. Sort of like a proxy I suppose.

After some basic research I think I need the following:

Antennae to receive RF
RF mixer to filter the frequencies
Oscillator to pass in the desired frequency to the RF mixer
Low pass filter to filter out the unwanted frequencies
Amplifier
Transmitter

And some sort of circuit board to put it all together. I'm curious how home brew electronics work with regards to circuit boards. I'd like the device to be as compact as possible, but don't mind if the prototype is a huge monstrosity.

I'll have a look around a bit further myself, but wondered if you had any pointers that might save me time and sanity.

Cheers,

Gordy

What frequency do you want to receive, and what frequency do you want
to convert it to?

A simple oscillator and mixer - potentially very simple - can do the
basic function, if you don't mind receiving image frequencies and
such. It would be a good place to start.


--

John Larkin Highland Technology, Inc

jlarkin at highlandtechnology dot com
http://www.highlandtechnology.com

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom laser controllers
Photonics and fiberoptic TTL data links
VME thermocouple, LVDT, synchro acquisition and simulation

 

[Michael Black]

On Mon, 16 Apr 2012, Tim Wescott wrote:

On Mon, 16 Apr 2012 02:19:57 -0700, gordon.is.a.moron wrote:

Hello,

I'm a complete electronics novice but would like to get involved at a
basic level. As a project I'd like to receive a radio frequency, convert
it, and then transmit it on to my radio receiver. Sort of like a proxy I
suppose.

After some basic research I think I need the following:

Antennae to receive RF
RF mixer to filter the frequencies
Oscillator to pass in the desired frequency to the RF mixer Low pass
filter to filter out the unwanted frequencies Amplifier
Transmitter

And some sort of circuit board to put it all together. I'm curious how
home brew electronics work with regards to circuit boards. I'd like the
device to be as compact as possible, but don't mind if the prototype is
a huge monstrosity.

I'll have a look around a bit further myself, but wondered if you had
any pointers that might save me time and sanity.

Cheers,

Gordy

I didn't want this answer to get lost in my other reply: what you're
thinking of building is a repeater or a translator (depending on who you
ask). If you want to look for a kit or on-line schematics, those are the
search terms to use.

I'm not sure that is what he wants. I read the "transmit to a receiver"

as "feed the mixer into the receiver". But since he hasnt' actually said
what he wants, just trying to interpret based on a little knowledge, it
certianly isnt' clear.

Michael

 

[John Fields]

On Mon, 16 Apr 2012 02:19:57 -0700 (PDT), gordon.is.a.moron@gmail.com
wrote:

Hello,

I'm a complete electronics novice but would like to get involved at a basic level. As a project I'd like to receive a radio frequency, convert it, and then transmit it on to my radio receiver. Sort of like a proxy I suppose.

After some basic research I think I need the following:

Antennae to receive RF
RF mixer to filter the frequencies
Oscillator to pass in the desired frequency to the RF mixer
Low pass filter to filter out the unwanted frequencies
Amplifier
Transmitter

And some sort of circuit board to put it all together. I'm curious how home brew electronics work with regards to circuit boards. I'd like the device to be as compact as possible, but don't mind if the prototype is a huge monstrosity.

I'll have a look around a bit further myself, but wondered if you had any pointers that might save me time and sanity.

Cheers,

Gordy

---
A simplistic version of what you're asking for, assuming that you're
only interested in dealing with a single input frequency, would
comprise an antenna tuned to that frequency followed by an RF
amplifier and a local oscillator feeding a mixer followed by a
bandpass filter.

The output of the bandpass filter would be connected to the RF input
of your radio, and might not be needed, depending on the input
banwidth of your radio and where, in the spectrum, you're working.

What kind of RF input signal and radio are you talking about?

--
JF

 

[Tim Wescott]

On Mon, 16 Apr 2012 17:27:56 -0400, Michael Black wrote:

On Mon, 16 Apr 2012, Tim Wescott wrote:

On Mon, 16 Apr 2012 02:19:57 -0700, gordon.is.a.moron wrote:

Hello,

I'm a complete electronics novice but would like to get involved at a
basic level. As a project I'd like to receive a radio frequency,
convert it, and then transmit it on to my radio receiver. Sort of like
a proxy I suppose.

After some basic research I think I need the following:

Antennae to receive RF
RF mixer to filter the frequencies
Oscillator to pass in the desired frequency to the RF mixer Low pass
filter to filter out the unwanted frequencies Amplifier Transmitter

And some sort of circuit board to put it all together. I'm curious how
home brew electronics work with regards to circuit boards. I'd like
the device to be as compact as possible, but don't mind if the
prototype is a huge monstrosity.

I'll have a look around a bit further myself, but wondered if you had
any pointers that might save me time and sanity.

Cheers,

Gordy

I didn't want this answer to get lost in my other reply: what you're
thinking of building is a repeater or a translator (depending on who
you ask). If you want to look for a kit or on-line schematics, those
are the search terms to use.

I'm not sure that is what he wants. I read the "transmit to a receiver"
as "feed the mixer into the receiver". But since he hasnt' actually
said what he wants, just trying to interpret based on a little
knowledge, it certianly isnt' clear.

Hmm. That hadn't occurred to me, because I unconsciously put "through
free space" after "transmit" (or maybe "receiver").

If he just wants to modify a receiver to work in a different band that
originally designed, he wants a converter. He can google for those, too,
but he'll get a lot of downconverters, and not a lot of old-style ham
radio converters (if that is, indeed, what he wants).

--
My liberal friends think I'm a conservative kook.
My conservative friends think I'm a liberal kook.
Why am I not happy that they have found common ground?

Tim Wescott, Communications, Control, Circuits & Software
http://www.wescottdesign.com

 

[Phil Allison]

<gordon.is.a.moron@gmail.com>

** What a good name.


Thanks everyone. What I'm trying to do is receive a UMTS signal from a
mobile phone network and then drop the frequency so my phone can receive it.
The revision of the phone is set up for GSM and can only do one frequency of
the UMTS pair that the network uses. I thought it would be an interesting
idea, though how attainable it is I don't know.

Anyway, the idea is receive the UMTS signal, drop it by 50mhz and then
transmit it to my phone. Hopefully I can receive the signal an pass it on
without having to authenticate the receiver in any way, such as registering
an IMEI or something.


** Got news for you - fuckwit.

A mobile phone is a TRANSCEIVER !

It is not a radio - it cannot be a receiver alone.



...... Phi

 

On Tuesday, 17 April 2012 10:55:33 UTC+12, John Fields wrote:

On Mon, 16 Apr 2012 02:19:57 -0700 (PDT), gordon.is.a.moron@gmail.com
wrote:

Hello,

I'm a complete electronics novice but would like to get involved at a basic level. As a project I'd like to receive a radio frequency, convert it, and then transmit it on to my radio receiver. Sort of like a proxy I suppose.

After some basic research I think I need the following:

Antennae to receive RF
RF mixer to filter the frequencies
Oscillator to pass in the desired frequency to the RF mixer
Low pass filter to filter out the unwanted frequencies
Amplifier
Transmitter

And some sort of circuit board to put it all together. I'm curious how home brew electronics work with regards to circuit boards. I'd like the device to be as compact as possible, but don't mind if the prototype is a huge monstrosity.

I'll have a look around a bit further myself, but wondered if you had any pointers that might save me time and sanity.

Cheers,

Gordy

---
A simplistic version of what you're asking for, assuming that you're
only interested in dealing with a single input frequency, would
comprise an antenna tuned to that frequency followed by an RF
amplifier and a local oscillator feeding a mixer followed by a
bandpass filter.

The output of the bandpass filter would be connected to the RF input
of your radio, and might not be needed, depending on the input
banwidth of your radio and where, in the spectrum, you're working.

What kind of RF input signal and radio are you talking about?

--
JF

Thanks everyone. What I'm trying to do is receive a UMTS signal from a mobile phone network and then drop the frequency so my phone can receive it. The revision of the phone is set up for GSM and can only do one frequency of the UMTS pair that the network uses. I thought it would be an interesting idea, though how attainable it is I don't know.

Anyway, the idea is receive the UMTS signal, drop it by 50mhz and then transmit it to my phone. Hopefully I can receive the signal an pass it on without having to authenticate the receiver in any way, such as registering an IMEI or something.

Cheers,
Gordy

 

[Jasen Betts]

On 2012-04-17, gordon.is.a.moron@gmail.com <gordon.is.a.moron@gmail.com> wrote:

Thanks everyone. What I'm trying to do is receive a UMTS signal from
a mobile phone network and then drop the frequency so my phone can
receive it. The revision of the phone is set up for GSM and can only
do one frequency of the UMTS pair that the network uses. I thought it
would be an interesting idea, though how attainable it is I don't
know.

probably not going to work.

Anyway, the idea is receive the UMTS signal, drop it by 50mhz and
then transmit it to my phone. Hopefully I can receive the signal an
pass it on without having to authenticate the receiver in any way,
such as registering an IMEI or something.

supposing your phone can see and understand the cell station, the first
thing it's going to try to do is register. and that's not going to work
without a transmit path.

I non't even know if UMTS and GSM are compatible enough that the phone
will even see the cell station, given that the data rates are so
different, I doubt that it will.

--
⚂⚃ 100% natural

--- Posted via news://freenews.netfront.net/ - Complaints to news@netfront.net ---

 

[George Herold]

On Apr 17, 6:38 am, gordon.is.a.mo...@gmail.com wrote:

On Tuesday, 17 April 2012 10:55:33 UTC+12, John Fields  wrote:
On Mon, 16 Apr 2012 02:19:57 -0700 (PDT), gordon.is.a.mo...@gmail.com
wrote:

Hello,

I'm a complete electronics novice but would like to get involved at a basic level. As a project I'd like to receive a radio frequency, convert it, and then transmit it on to my radio receiver. Sort of like a proxy I suppose.

After some basic research I think I need the following:

Antennae to receive RF
RF mixer to filter the frequencies
Oscillator to pass in the desired frequency to the RF mixer
Low pass filter to filter out the unwanted frequencies
Amplifier
Transmitter

And some sort of circuit board to put it all together. I'm curious how home brew electronics work with regards to circuit boards. I'd like the device to be as compact as possible, but don't mind if the prototype is a huge monstrosity.

I'll have a look around a bit further myself, but wondered if you had any pointers that might save me time and sanity.

Cheers,

Gordy

---
A simplistic version of what you're asking for, assuming that you're
only interested in dealing with a single input frequency, would
comprise an antenna tuned to that frequency followed by an RF
amplifier and a local oscillator feeding a mixer followed by a
bandpass filter.

The output of the bandpass filter would be connected to the RF input
of your radio, and might not be needed, depending on the input
banwidth of your radio and where, in the spectrum, you're working.

What kind of RF input signal and radio are you talking about?

--
JF

Thanks everyone. What I'm trying to do is receive a UMTS signal from a mobile phone network and then drop the frequency so my phone can receive it. The revision of the phone is set up for GSM and can only do one frequency of the UMTS pair that the network uses. I thought it would be an interesting idea, though how attainable it is I don't know.

Anyway, the idea is receive the UMTS signal, drop it by 50mhz and then transmit it to my phone. Hopefully I can receive the signal an pass it on without having to authenticate the receiver in any way, such as registering an IMEI or something.

Cheers,
Gordy- Hide quoted text -

- Show quoted text -

Ah, that sounds hard! and possibly illegal. Why not just buy a new
cell phone?

George H.

 

[Tim Wescott]

On Tue, 17 Apr 2012 21:20:38 +1000, Phil Allison wrote:

gordon.is.a.moron@gmail.com

** What a good name.


Thanks everyone. What I'm trying to do is receive a UMTS signal from a
mobile phone network and then drop the frequency so my phone can receive
it. The revision of the phone is set up for GSM and can only do one
frequency of the UMTS pair that the network uses. I thought it would be
an interesting idea, though how attainable it is I don't know.

Anyway, the idea is receive the UMTS signal, drop it by 50mhz and then
transmit it to my phone. Hopefully I can receive the signal an pass it
on without having to authenticate the receiver in any way, such as
registering an IMEI or something.


** Got news for you - fuckwit.

A mobile phone is a TRANSCEIVER !

It is not a radio - it cannot be a receiver alone.

(Newbie note: we all learn to ignore Phil when he's off his meds. This
is USENET; there's some whackos -- and, well. Anyway)

--
My liberal friends think I'm a conservative kook.
My conservative friends think I'm a liberal kook.
Why am I not happy that they have found common ground?

Tim Wescott, Communications, Control, Circuits & Software
http://www.wescottdesign.com

 

[Phil Allison]

"Tim Wescott" = RETARDED PIG

gordon.is.a.moron@gmail.com

** What a good name.


Thanks everyone. What I'm trying to do is receive a UMTS signal from a
mobile phone network and then drop the frequency so my phone can receive
it. The revision of the phone is set up for GSM and can only do one
frequency of the UMTS pair that the network uses. I thought it would be
an interesting idea, though how attainable it is I don't know.

Anyway, the idea is receive the UMTS signal, drop it by 50mhz and then
transmit it to my phone. Hopefully I can receive the signal an pass it
on without having to authenticate the receiver in any way, such as
registering an IMEI or something.


** Got news for you - fuckwit.

A mobile phone is a TRANSCEIVER !

It is not a radio - it cannot be a receiver alone.

(Newbie note: we all learn to ignore Phil when he's off his meds. This
is USENET; there's some whackos -- and, well. Anyway)

** What the FUCK is the matter with you - fuckhead ????

My post is 100% correct and the OP is an UTTER MORON !!!!

Can you the fucking idiot's name ???

Got any idea why he uses it ?

Why don't you FOAD you stinking pile of autistic, sub human garbage.



..... Phil

 

[Tim Wescott]

On Tue, 17 Apr 2012 03:38:56 -0700, gordon.is.a.moron wrote:

On Tuesday, 17 April 2012 10:55:33 UTC+12, John Fields wrote:
On Mon, 16 Apr 2012 02:19:57 -0700 (PDT), gordon.is.a.moron@gmail.com
wrote:

Hello,

I'm a complete electronics novice but would like to get involved at a
basic level. As a project I'd like to receive a radio frequency,
convert it, and then transmit it on to my radio receiver. Sort of like
a proxy I suppose.

After some basic research I think I need the following:

Antennae to receive RF
RF mixer to filter the frequencies
Oscillator to pass in the desired frequency to the RF mixer Low pass
filter to filter out the unwanted frequencies Amplifier
Transmitter

And some sort of circuit board to put it all together. I'm curious how
home brew electronics work with regards to circuit boards. I'd like
the device to be as compact as possible, but don't mind if the
prototype is a huge monstrosity.

I'll have a look around a bit further myself, but wondered if you had
any pointers that might save me time and sanity.

Cheers,

Gordy

---
A simplistic version of what you're asking for, assuming that you're
only interested in dealing with a single input frequency, would
comprise an antenna tuned to that frequency followed by an RF amplifier
and a local oscillator feeding a mixer followed by a bandpass filter.

The output of the bandpass filter would be connected to the RF input of
your radio, and might not be needed, depending on the input banwidth of
your radio and where, in the spectrum, you're working.

What kind of RF input signal and radio are you talking about?

--
JF

Thanks everyone. What I'm trying to do is receive a UMTS signal from a
mobile phone network and then drop the frequency so my phone can receive
it. The revision of the phone is set up for GSM and can only do one
frequency of the UMTS pair that the network uses. I thought it would be
an interesting idea, though how attainable it is I don't know.

Anyway, the idea is receive the UMTS signal, drop it by 50mhz and then
transmit it to my phone. Hopefully I can receive the signal an pass it
on without having to authenticate the receiver in any way, such as
registering an IMEI or something.

As mentioned, there's a lot more going on between UMTS and GSM than just
the frequency difference. It probably can't be done in any way that's
simpler than building a phone and a base and hooking them up.


--
My liberal friends think I'm a conservative kook.
My conservative friends think I'm a liberal kook.
Why am I not happy that they have found common ground?

Tim Wescott, Communications, Control, Circuits & Software
http://www.wescottdesign.com

 

[Bill Bowden]

On Apr 16, 9:15 am, Bob Myers <bobmyer...@gmail.com> wrote:

On Monday, April 16, 2012 3:19:57 AM UTC-6, gordon.i...@gmail.com wrote:
Hello,

I'm a complete electronics novice but would like to get involved at a basic level. As a project I'd like to receive a radio frequency, convert it, and then transmit it on to my radio receiver. Sort of like a proxy I suppose.

After some basic research I think I need the following:

Antennae to receive RF
RF mixer to filter the frequencies
Oscillator to pass in the desired frequency to the RF mixer
Low pass filter to filter out the unwanted frequencies
Amplifier
Transmitter

And some sort of circuit board to put it all together. I'm curious how home brew electronics work with regards to circuit boards. I'd like the device to be as compact as possible, but don't mind if the prototype is a huge monstrosity.

I'll have a look around a bit further myself, but wondered if you had any pointers that might save me time and sanity.

Cheers,

Gordy

I would agree with the suggestion that you start looking for a basic receiver design to start with - but would say that even that's a bit of a stretch if you are a "complete electronics novice."

What you are trying to do IS basically what's called a "superheterodyne" receiver, which describes the vast majority of radio receivers out there today anyway.  The hallmark of a "superhet" design is that it converts all incoming frequencies to a common "intermediate frequency" which is then amplified and demodulated.  Getting a copy of a good basic text on radio - the ARRL Radio Amateur's Handbook" might be a good place to start - would be a great start in the right direction.  (It's really too bad that the good ol' classic Heathkits are no longer available.  However, there are still some basic receiver kits available to get started with, like:

http://www.amazon.com/Ramsey-SR2C-Shortwave-Receiver-Kit/dp/B0002NRL9I

http://www.tentec.com/products/9%252dBand-SW-Receiver.html(not a superhet, but could be fun))

One minor gotcha in building a superhet is that this type of receiver requires an adjustment process ("alignment") to get everything working properly together - it's not impossibly difficult, but again may be a bit much for the real novice to pull off, especially without some test equipment.

Bob M.

Yes, it requires quite a few repeated adjustments to get everything
right. I managed to make an AM broadcast superhet using the NE602
balanced modulator, and there are several adjustments to be repeated
to get things right. I learned how to do it working in a radio factory
for 6 months.

http://www.bowdenshobbycircuits.info/radio.htm#radio.gif

-Bill

 

[Ian Wiles]

On Wednesday, 18 April 2012 15:07:45 UTC+12, Tim Wescott wrote:

On Tue, 17 Apr 2012 03:38:56 -0700, gordon.is.a.moron wrote:

On Tuesday, 17 April 2012 10:55:33 UTC+12, John Fields wrote:
On Mon, 16 Apr 2012 02:19:57 -0700 (PDT), gordon.is.a.moron@gmail.com
wrote:

Hello,

I'm a complete electronics novice but would like to get involved at a
basic level. As a project I'd like to receive a radio frequency,
convert it, and then transmit it on to my radio receiver. Sort of like
a proxy I suppose.

After some basic research I think I need the following:

Antennae to receive RF
RF mixer to filter the frequencies
Oscillator to pass in the desired frequency to the RF mixer Low pass
filter to filter out the unwanted frequencies Amplifier
Transmitter

And some sort of circuit board to put it all together. I'm curious how
home brew electronics work with regards to circuit boards. I'd like
the device to be as compact as possible, but don't mind if the
prototype is a huge monstrosity.

I'll have a look around a bit further myself, but wondered if you had
any pointers that might save me time and sanity.

Cheers,

Gordy

---
A simplistic version of what you're asking for, assuming that you're
only interested in dealing with a single input frequency, would
comprise an antenna tuned to that frequency followed by an RF amplifier
and a local oscillator feeding a mixer followed by a bandpass filter.

The output of the bandpass filter would be connected to the RF input of
your radio, and might not be needed, depending on the input banwidth of
your radio and where, in the spectrum, you're working.

What kind of RF input signal and radio are you talking about?

--
JF

Thanks everyone. What I'm trying to do is receive a UMTS signal from a
mobile phone network and then drop the frequency so my phone can receive
it. The revision of the phone is set up for GSM and can only do one
frequency of the UMTS pair that the network uses. I thought it would be
an interesting idea, though how attainable it is I don't know.

Anyway, the idea is receive the UMTS signal, drop it by 50mhz and then
transmit it to my phone. Hopefully I can receive the signal an pass it
on without having to authenticate the receiver in any way, such as
registering an IMEI or something.

As mentioned, there's a lot more going on between UMTS and GSM than just
the frequency difference. It probably can't be done in any way that's
simpler than building a phone and a base and hooking them up.


--
My liberal friends think I'm a conservative kook.
My conservative friends think I'm a liberal kook.
Why am I not happy that they have found common ground?

Tim Wescott, Communications, Control, Circuits & Software
http://www.wescottdesign.com

Ah ok, not that surprising then. I thought it would be an interesting idea. Oh by the way, it doesn't involve converting GSM to UMTS or GSM at all - It's UMTS all the way, what I meant to say was the phone was GSM biased in that it supported GSM networks better than UMTS. But yes, sounds impractical really. I thought it would be an interesting project. Oh well, thanks everyone.

Cheers,

Gordy.