my tablet SGH-1497 which I was using for some time (10 months earlier) using my home wifi, does not recognize the same wifi now and shows the error Not in range, when I try to add my wifi details under settings for Wi-Fi
Did you try to reset network settings on tablet yet? I would try that first.
Next, I would try to use your phone as a "hotspot" (if possible), and try to connect your tablet that way. If it still doesn't recognize your "hotspot", then there might be a hardware issue with your tablet.
You can also try to reset your entire router/modem. Unplug for about 45 seconds then plug everything back in and check.
In the case it doesn't work, I suggest taking it to your local certified Samsung repair shop or call 1-800-SAMSUNG and they can direct you on how to get your tablet fixed/mailed in.
I hope this bit of info helps in any way.