Do all radio receivers have an IF somewhere in them. Do portable radios? Is there an easy way to find where it is in the circuit without just going crazy with an oscilloscope looking for 450 khz or whatever?

 

All Supersonic Heterodyning receivers do at least.
That's 455kHz or whatever.. usually.. for AM MW.

Relating this to every schematic is the part I'm working on

 

"Supersonic Heterodyning" -- ROFLMAO
Where'd you get that curious turn of phrase?

There are such things as direct conversion receivers, and not all IF frequencies are 455 kHz.

http://en.wikipedia.org/wiki/Superheterodyne_receiver

 

Not all radios are based on the superheterodyne receiver principle though a large percentage of commercially available radios use this method. The most common IF frequency is 455kHz.

Many receivers use double conversion and triple conversion techniques where there
could be two or three IF amplifiers.

A direct-conversion receiver uses an oscillator that is set to the same frequency as the incoming RF signal resulting in a direct-to-baseband signal.

Regenerative receivers use a prinicple of positive feedback to amplify the incoming signal directly.

Edit: I wrote this as post #2 and was called away to answer the phone.

 

"Supersonic Heterodyning" -- ROFLMAO
Where'd you get that curious turn of phrase?

There are such things as direct conversion receivers, and not all IF frequencies are 455 kHz.

http://en.wikipedia.org/wiki/Superheterodyne_receiver

When I went to an antique radio dealer, I wanted to really turn it on, so I asked for a
Thermonic Electron Valve for my Supersonic Heterodyning Meduim Wave Broadcast Receiver.

You should be proud of me Papabravo, I took the time to discover the meaning of those big words individually
and two months ago, I had no idea.

 

"Supersonic Heterodyning" -- ROFLMAO

I don't think anyone uses that term. It was known as "superhet" but even that is almost extinct.

 

I am proud of you Art. Malaprops are a high and sophisticated brand of humor. I treasure each and every one.

http://en.wikipedia.org/wiki/Malapropism

 

Malapropism:
http://en.wikipedia.org/wiki/Malapropism
Supersonic:
http://en.wikipedia.org/wiki/Supersonic_speed
Heterodyning:
http://en.wikipedia.org/wiki/Heterodyne

Yes it is Humour, but how is the OP not cleverer for following suit?

 

but how is the OP not cleverer for following suit?

Hmmmmmmmmmmmmmmmmm?
^512Hz----------------------------^16.3kHz

 

Hello,

Have a look at the following page:
http://www.mikroe.com/old/books/rrbook/chapter4/chapter4a.htm

You can also have a look a the NEETS series.
http://www.phy.davidson.edu/instrumentation/NEETS.htm
Volume 17 is about radio communication.
The pages 2-11 and 2-12 show the super heterodyne in figure 2-9.

Bertus

 

portable radios (modern ones anyway) use 455 khz for am if's, and 10.7mhz fm if's. there are some single chip radios that do away with the transformers with a lower frequency if and opamp based active filters.
cliff