crystal radio earth problems

[RobertMWillis]

lately i have built a crystal radio and i tested it using a cold water pipe at our school and worked perfectly but when i tested it at my house and would not work, but if i touch the lead that is attached to the earpiece and diode i get a constant buzz sound.

this buzz sound would change volume depending where i test it around my house leading me two two conclusions

1 the gnd is not good enough
2 the underground mains wire is interfering (our suburb has its power underground)

so the question i have is could there be anything else interfering with the radio and how do i mitigate it and how would i go about getting/making a better ground

[tkamiya]

The buzzzzz sound you hear is your mains power (house AC) being picked up by your body.  As you get closer or further from appliances or wires inside wall, volume will change.

The reason your pipe ground doesn't work is probably because you have PVC pipe.  Obviously, it is not conductive, so it won't perform as a ground.

You could, perhaps, get a better result if you improve your antenna (longer and higher) and find another suitable ground.  Relatively large metal structure, such as your window frame can act as ground, even if it not connected to ground.  OR, you could hunt down where your ground rod is, and hook it up to that.  By the way, too long of ground wire will end up acting like another antenna. 

In my young days, I used to have a long wire for antenna, and used my own body as ground.  Not the smartest of things to do but worked.  Danger involved in this would be, if my antenna are to touch another voltage source or get hit by lightening, I'll be fried.