Perhaps inspired by my recent , many friends start building science projects of post , many friends start building science projects of ScienceWiz / Inventions Kit

with their kids

,

However, they could not get the last project of "Building a Radio" work.





Frankly, my son and I did not make it at our first attempt, either. Apparently,

we are not alone.

For example, this amazon reviewer complained it even though he "

followed the instructions to a tee". This boy on

was not able to get any sound even though he double checked everything.





Almost gave up until I read this successful case with the

same

t as ours

. Then I did some online research and troubleshooting, eventually made it work! My son was so excited to

hear the music out of the homemade radio.





Now, I like to share some troubleshooting tips. Hopefully, these trigger your a "Aha moment" and

help you fix your Radio...

Double check your circuitry

Check the wiring carefully against the schematic diagram, making sure that all the connections make good contact. The cardboard should sit on top of an insulated material (wooden table or plastics), so no short circuit between the paper fasteners.





E arphone

Don't use your iPhone or smartphone headset, o

nly used the earphone in the kit . A

low impedance

earphone that you typically use in your MP3 player or smartphone will not work.





Sand magnet wire completely

Unlike the motor project , you have to COMPLETELY remove the protective enamel off the two ends of the coiled wire. I used a piece of 220-Grit sandpaper (not the low quality pieces from the kit) and re-sanded them.





Grounding

The ground is critical and should be True ground, something like a metal water pipe in your house

all the way to the earthen ground pipe.

The tip I got is shown on the right picture. I found a cable outlet (BNC connector) on the wall, so I just connected my red ground wire to the outer surface of the cable outlet, which is a better ground.





Antenna

A long enough antenna (>90ft).

If space is a problem, you can try winding the antenna around the room in a big coil, but having the antenna outdoors, and as high up as you can get it, will be best.

is is to use your body as an antenna - simply hold the slidable outer foil on the towel tube (one electrode of the variable capacitor), but don't touch the inner foil (if you do so, you short circuit the variable capacitor).





For our case, after re-sanding, grounding to the cable outlet, and touching the outer foil, we immediately heard the radio sound. What an exciting moment!





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