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Don Meredith
(donmeredith) - F

Locale: SouthEast
Three Penny Radio on 11/20/2008 06:57:50 MST Print View

I saw this on the MAKE blog and thought it was right down our light-weight do it yourself alley. Enjoy:

http://blog.makezine.com/archive/2008/11/build_a_three_penny_radio.html?CMP=OTC-0D6B48984890

Rog Tallbloke
(tallbloke) - F

Locale: DON'T LOOK DOWN!!
Re: Three Penny Radio on 11/20/2008 07:20:36 MST Print View

Nice link Don.
From the article
"A crystal radio is nice because it needs no power, and the materials can all be home-made or at least found around the house. But the crystal radio needs a big antenna, and a good ground, and so is not very portable.
To get away with using a much smaller, portable antenna, we will need to amplify the tiny signal it receives. This requires a portable power supply, such as a battery."

Surely with the three pennies, some lemon juice, and a bit of engineuity(!) we could make the battery too!

Many (many) years ago, my friend and I built mini radios using crystals and the smallest 1.5v battery we could get into 'tic-tac' mint boxes. They used deaf aid earphones for the low resistance and tinny sound...

I've just orderd some free samples from Texas Instruments for a new power generation project I'm working on. If all goes to plan, we'll be able to power the radio, and some speakers, with wood, and recharge the cellphone at the same time. :-)

Devin Montgomery
(dsmontgomery) - MLife

Locale: one snowball away from big trouble
Re: Three Penny Radio on 11/20/2008 11:25:23 MST Print View

So do you think Tang (I wonder what its pH is...) could be used in place of the lemon juice for the battery, and that you could hook it up to an Aluminum trekking pole for better reception? :)

Rog Tallbloke
(tallbloke) - F

Locale: DON'T LOOK DOWN!!
Re: Re: Three Penny Radio on 11/20/2008 11:44:42 MST Print View

"Sorry it's a bit draughty in here tonight love, I'm trying to pick up the NFL results"

Lol. :-)

Edited by tallbloke on 11/20/2008 11:46:09 MST.

Bob Ellenberg
(BobTheBuilder) - F
crystal radio on 11/27/2008 20:16:46 MST Print View

I made several of them as a kid (45-50 years ago) and don't remember the antenna being anything more than a length of very thin wire. I remember sneaking it to church and having the wire inside my shirt. Not sure what they would received out in the woods these days but the nostalgic thoughts are nice.

Bob Ellenberg
(BobTheBuilder) - F
Light weight model with no antenna on 11/27/2008 20:28:07 MST Print View

OK, this subject interested me so I started looking. Here is one http://journeytoforever.org/edu_xtal/XTAL.HTM (scroll half way down to the computer ribbon cable and then go to the details). It weighs almost nothing, is sensitive and needsd no seperate antenna or ground. Your IPOD can play music but can't pick up weather or news and doesn't have that MYOG sense of accomplishment.