Radio Shack Pocket Radio Uses Silicon Chip

Vimal writes:

Refer to my earlier post on radio shack pocket radio 12-586 as above.My observation proves that it's a silicon chip Si4831-B30 based mechanical tuning AM/FM Radio receiver,similar to Kaito KA321(Degen DE321).
So we have a DSP radio in disguise from RADIO SHACK.

http://www.silabs.com/Support%20Documents/TechnicalDocs/Si4831-35-B30.pdf

Comments

[Michael Brent]

I got one of these a while back.
They really do work well.
Now I know why.

[Angelo]

The hell with the I-Phone 5. THIS is the technology I want----and it's on a sixteen dollar pocket radio! Radio Shack, here I come.

[Gary]

Jay Allen reviewed this radio.

http://radiojayallen.com/shirt-pocket-amfm-portables-5-radios-compared/

[Keith Beesley]

I have a three- or four-year-old RS AM-FM-TV-weather pocket radio, now discontinued, that has superior reception on AM, FM, and NOAA weather bands (although the TV audio bands are useless, post-DTV conversion). I wonder if it also contains a SiLabs chip?

[Angelo]

I just bought the Radio Shack version yesterday. I have to say----I was blown away by the amount of AM stations it pulled in last night----and they were clear and steady enough to actually listen to. From my home in the Washington, DC area, I easily picked up Richmond, Virginia and New York----loud and clear----and some more distant signals not quite as clearly, but still acceptable. It actually rivaled my "real" radios for AM station stalking.

[Paul]

Does the radio have a ferrite bar?

[vimal oberoi]

Yes almost all AM radios have a ferrite bar.

[Angelo]

I haven't taken the back of my little radio----but I don't see a ferrite bar on the one in this photo???

[vimal oberoi]

It's on the other side of pcb,on top,near numbers written,you can see two screws for ferrite fixture.

[Drive-In-Freak]

Is the good ol' well known superhet circuit becoming a thing of the past?

I see no i.f. cans, no oscillator, no trim caps...almost nothing that looks like a radio circuit.

The new "dsp" radios confuse me to no end. They work and they seem to work reasonably well, but how they do it I don't understand at all.

[Gdk2008uk]

it's like this a little bit of C++ code will set the record straight.

#include
#include
#include
#include

int k=0;
long double XA[2][20]={{0.0},{0.0}};
long double YA[2][20]={{0.0},{0.0}};

int AM_DEMOD(int SIGNAL)
{
int i,result;
long double PHI;

PHI=((10695*3.141592671)/48000);
XA[0][0]=(SIGNAL*COS(k*PHI));
XA[1][0]=(SIGNAL*SIN(k*PHI));
YA[0][0]=((YA[0][1]-YA[0][2])+(XA[0][0]-XA[0][12]));
YA[1][0]=((YA[1][1]-YA[1][2])+(XA[1][0]-XA[1][12]));
k++;
result=((int)(32768*sqrt((YA[0][0]*YA[0][0])+(YA[1][0]*YA[1][0]))));
for(i=0;i<19;i++)
{
XA[0][19-i]=XA[0][18-i];
YA[0][19-i]=YA[0][18-i];
XA[1][19-i]=XA[1][18-i];
YA[1][19-i]=YA[1][18-i];
}
return result;
}

void main(void)
{
srand(1066);
do
{
printf("%d\r\n",AM_DEMOD(rand()));
}while(kbhit());
getchar();
exit(0);
}

[Gdk2008uk]

Something has removed the include headers which are stdlib.h,stdio.h,conio.h,float.h and math.h

[Dean]

Degen is the manufacturer who makes this #12-586 AM/FM pocket radio for Radio Shack. That's pretty obvious. It's an excellent handheld on both AM/FM bands with above satisfactory sensitivity and selectivity. Not a bad unit for lightweight DX'ing. The only minor drawbacks with this radio are the dials on both the left and right side. They are too small and a little too stiff.