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Copyright © Austin
Hellier 10/01/2001
Diagram 1. MK484 Radio Receiver for the AM Band
Build This Modern AM Radio
Receiver For Just $12.00!
This adaption of the famous ZN414 (now MK484 plastic pack) AM radio
receiver, was inspired by the fact that I live fairly close to my
three local AM stations (2WL, 2WN and the ethnic broadcaster 2RPH)
and would normally receive overloaded signals with a standard TRF
design based on this IC. With the minor modifications made to the
basic design as shown, and with the aid of the inductive coupling
arrangement, i can pick up all three stations with clarity and volume,
and with hardly any (and I mean ANY) interference from each other,
and no oscillations!
Make sure that you wire the MK484 (IC1) up correctly - the pinouts
shown above are seen from the top of the device. Wind L2 so that
it fits snugly on the end of the rod, right next to the end of L1
's winding. The average 9 volt battery gives much better volume
and selectivity, and should last for some months of constant use
- if you've got a few spare $, try a new Eveready Lithium or the
new Kodak Alkaline!
MK484 ICs are available from http://www.dse.com.au/
(cat# Z6525 for $2.36AUD).
Construction
You can make this circuit up quickly on your SK-10 panel,
or use something like the Dick Smith "Funway #1"
blue plastic block, screws and washers to build the radio
on. Make sure that you keep the wiring from the battery and
the coils away from each other, otherwise you may have feedback
problems. Try winding ten turns of insulated hookup wire around
a paper roll tube. This may allow you to pick up some shortwave
stations (eg: Radio Australia, Voice of America, Greenwich
Meantime pips etc) with the aid of a small (10 metre) aerial
wire. You can also power this design from beer or acidic soft
drinks (sodas) by making a simple battery from several jam
jars, the beer etc. and some zinc and copper strips, sitting
in the liquid - interesting experiment... Happy listening! |
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| Parts List |
DSE# |
| IC1 |
MK 484 |
Z6525 |
| VC1 |
160+60pF |
R2970 |
| Rod |
100x9mm |
R5100 |
| C1 |
0.01uMKT |
R3012 |
| C2 |
O 1 u MKT |
R3025 |
| R1 |
100K.25W |
Rl124 |
| R2 |
6K8.25W |
R1094 |
| BB |
Blue Board |
H4050 |
This receiver works best from the 9 volt
(eg Eveready 216) battery supply.
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