Original Ideas Required for Radio Receiver :)

Original Ideas Required for Radio Receiver :)

Post by Stephen William Simps » Wed, 08 Mar 1995 11:14:55

Hola Everyone,

        I'm a third year undergraduate at the university of Canterbury NZ, and
I need some help.

        I decided to do a comms paper this year, it has one project : design
and make your own radio.  Fine easy you say... except that the marker likes
original ideas.

        Last year one of the students taking the course spent a fairly
substantial sum of money to build a radio complete with surround sound etc.
etc.  He got about 90%, but a smart young fellow built a crystal set and got
92%.  The reason he got such a high mark was because he made his own diode out
of some sought of crystal he requisitioned from physics.

        So my problem is to find an original idea for a radio which falls into
these catergories (in order of importance).

        1:  It needs to be original, I thought of extending the idea of the
crystal set a little by making my own tuning capacitor out of some of those old
fashioned razor blades (has anyone tried this?).  Someone built a 'Co-hearer'
radio last year, that got good marks.  Does anyone know of any unusaul am
receivers (the older the technology the better), or know of any books
describing early radio recievers?

        2:  The idea has to be reasonably easy to understand by an ignorant
undergrad, and has to be reasonably easy to implement.

        3:  I'd prefer it if I don't have to take out a mortgage ;)

Cheers,

Stephen Simpson

PS.  Please email my elec account as I read it more frequently.


 
 
 

Original Ideas Required for Radio Receiver :)

Post by Gordon Symon » Thu, 09 Mar 1995 03:42:52


Why don't you go one better and build a self-powered radio?  You can
use two tuned circuits with crystal detectors to form + and -
power supplies to power a single (germanium) transistor audio
amplifier.  You will need a *high* efficiency speaker like an old
horn (earphone with bell).

Oddly enough, you only need one aerial for both power supplies and the
radio itself.

The first one of these I saw had a crystal detector followed by
a single transistor audio amplifier.

All kinds of advantages - you listen or free, absorb the stations you
hate (tune the power supply to them!) and show how clever you are!

This is guaranteed to attract attention.  One caution - as the guy
who wrote this up in the ARCA journal (Bud Bedker) correctly discovered,
it is a good idea to included an on/off switch for when you get tired
of listening to it.

 
 
 

Original Ideas Required for Radio Receiver :)

Post by Leon Hell » Thu, 09 Mar 1995 05:59:49



Quote:>         So my problem is to find an original idea for a radio which falls into
> these catergories (in order of importance).

>         1:  It needs to be original, I thought of extending the idea of the
> crystal set a little by making my own tuning capacitor out of some of those old
> fashioned razor blades (has anyone tried this?).  Someone built a 'Co-hearer'
> radio last year, that got good marks.  Does anyone know of any unusaul am
> receivers (the older the technology the better), or know of any books
> describing early radio recievers?

>         2:  The idea has to be reasonably easy to understand by an ignorant
> undergrad, and has to be reasonably easy to implement.

>         3:  I'd prefer it if I don't have to take out a mortgage ;)

How about making your own point-contact transistor and using that as
the basis for a single-transistor Rx? If someone got high marks for making
his own diode you should get even more for a transistor. 8-)

Leon
--
Leon Heller                       | "Do not adjust your mind, there is
G1HSM                             |  a fault in reality": on a wall

Phone: +44 (01734) 266679         |

 
 
 

Original Ideas Required for Radio Receiver :)

Post by David Stockt » Sat, 11 Mar 1995 02:27:07


: Hola Everyone,

:       I'm a third year undergraduate at the university of Canterbury NZ, and
: I need some help.

:       I decided to do a comms paper this year, it has one project : design
: and make your own radio.  Fine easy you say... except that the marker likes
: original ideas.

    Then you must think of your own idea, or else it won't be original.

   That other bloke's surround-sound job was probably little more than
the result of a lot of money, a lot of hours work, and the diligent
reading of published designs/applications notes. Creativity level: low

   The guy with the crystal set was smart enough to choose something of
a sensible scale, and did it in a way that is unusual today. Duplicating
his effort even with a home-made capacitor is now not very original.
Your marker is doing his best to help you, he is trying to get you to
explore, not follow.

   If he said "make" rather than "build" or "assemble", what proportion
of components should be homebrew?

   What sort of lab equipment do you have access to? think
physics/mechanical more than electronic..

   Your choice should be bold, not gung-ho, so that even an unsuccessful
attempt is meritorious rather than foolhardy.

  It's the 50th anniversary of the freeing of Colditz, some prisoners of
war built their own radios out of whatever they could get their hands
on. What difference could modern knowledge make?

  Espionage agencies put radios, usually simple transmitters, into
innocuous objects. You could elect for modern components and let your
sense of humour loose on choice of housing.

   Could you make a radio using technology of an age earlier than the
discovery of radio waves?  (I've just had a crazy image of how the
Spanish inquisition would have made a variable capacitor, and a
point-contact transistor from ancient Egypt... I might just have a go at
this myself, just for a laugh, and as a conversation piece for the local
radio club)

  These are examples, but, I'm sorry, I've spoiled their originality by
suggesting them. Go and read some old books and magazines, go looking
for inspiration in unlikely places. Cooking up something entirely on
your own, without anyone else helping is great fun. Turn over stones,
kiss frogs, there's inspiration out there and no-one can ever predict
where. The right idea will make you smile.

   Cheers
         David  GM4ZNX

 
 
 

Original Ideas Required for Radio Receiver :)

Post by Gary Coffm » Sun, 12 Mar 1995 02:20:24


Quote:>Hola Everyone,
>    I'm a third year undergraduate at the university of Canterbury NZ, and
>I need some help.

>    I decided to do a comms paper this year, it has one project : design
>and make your own radio.  Fine easy you say... except that the marker likes
>original ideas.

>    Last year one of the students taking the course spent a fairly
>substantial sum of money to build a radio complete with surround sound etc.
>etc.  He got about 90%, but a smart young fellow built a crystal set and got
>92%.  The reason he got such a high mark was because he made his own diode out
>of some sought of crystal he requisitioned from physics.

That's a rip, the crystal set was one of the first and most primitive
receivers, hardly any originality there. The other guy probably just
copied a design too, but at least it was more involved. But Ok, it gives
us an idea of what the instructor is looking for. Let's see if we can
impress him without going overboard on the historical reenactments.

How about a selective TRF receiver that uses *no coils*. That should
baffle him for a moment. Hint: the answer begins with "g". Let's see
if you've learned anything yet.

Gary

--
Gary Coffman KE4ZV          |    You make it,     | gatech!wa4mei!ke4zv!gary
Destructive Testing Systems |    we break it.     | emory!kd4nc!ke4zv!gary

Lawrenceville, GA 30244     |                     |

 
 
 

Original Ideas Required for Radio Receiver :)

Post by Steven Merrifie » Wed, 15 Mar 1995 10:58:17

Quote:

>:   I'm a third year undergraduate at the university of Canterbury NZ, and
>: I need some help.

>:   I decided to do a comms paper this year, it has one project : design
>: and make your own radio.  Fine easy you say... except that the marker likes
>: original ideas.

I've been following this thread for a while now, and it seems that eveyone
is suggesting ideas to do with old/obsolete technology. Why look to the past
for *original* ideas - look to the future!

How about using a uP/DSP chip? or writing some really fancy code for say,
a soundblaster card, and mix the RF down to audio using software?

The future is reliant on original ideas - sure, look to the past for pointers,
but don't base your project on the past - comms is a futuristic area - go with
it!

=====================================================================
                           Steve Merrifield


 The Web: http://www.ee.latrobe.edu.au/postgrad/steve/steve.html
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