Amateur Radio Stack Exchange
Amateur Radio Stack Exchange

Questions tagged [crystal-radio]

9 questions
6
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2 answers

Why does capacitive loose coupling increase selectivity?

There are multiple ways to couple antennas. It is said that an antenna is capacitive loose coupled if a small capacitor is used between the antenna and the parallel resonant circuit (like C2 in the image below). Such a loose coupling will increase…
dudekowsky
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4
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1 answer

Building a crystal radio with my brother. How does this circuit work?

I'll be visiting home soon after school lets out, and I want to build an AM crystal radio with my little brother. This is the design we'll use: http://crystalradio.net/beginners/ I'll be doing my best to explain to him how this works. I understand…
BitPusher16
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4
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2 answers

Can I create a functional crystal radio using a plastic coil filled with seawater as the inductor?

Pex is cheap and comes pre-coiled, 3/8" pex is 0.360" ID. 1/2" is 0.485" ID Fill with "sea water" using distilled water and sea salt to proper concentration. Use for AM and/or Shortwave coil. Sea water is HIGHLY conductive and interacts with radio…
Aerothorn
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3
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3 answers

How do I get my crystal radio to receive?

My 8 year old and I are trying to figure out how to get this crystal radio we made working. It's based off this youtube video. We get clicks when we put the crystal ear piece either side of the resistor but nothing more yet. My son tried a really…
Agent Zebra
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3
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1 answer

feasibility of wireless passive crystal earphones

I just learnt about such a thing as a crystal radio receiver and the following idea came to my mind. I have no background knowledge on electronics nor anything related. What if battery-less earbuds can be made, picking AM waves from very short range…
user2464424
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3
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1 answer

Multi-band Crystal Receiver?

I'm just getting into radio (inspired by YouTube videos), and like many, I plan to start by building a crystal set (or multiples) before moving up to vacuum tubes (which I prefer over transistors). All the crystal set schematics I've seen, however,…
Zeiss Ikon
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3
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1 answer

Air Coil AM & Shortwave Crystal Radio Using 1/4" Copper Tubing

Looking to build a crystal radio, need help with the coil. I'm looking to get something to work with 1/4" thin wall copper tubing. Already have some nice diodes and whatever capacitors/resistors I need. I don't care if it is AM or shortwave, I can…
user13773
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2 answers

Type of Ground Wire for an AM Crystal Radio - I'm using a longwire antenna

I have way too many choices for ground wire. I am using a crystal radio so I need the BEST not just what will 'get by'. I've seen solid copper 10gauge, aluminum wire etc. I've also seen wide flat Braided tin coated copper braids. This looks…
randy k
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What is an expected sensitivity of a crystal radio for 7 MHz band?

I'm learning to build radio receivers and transmitters. I've successfully build some oscillators, amplifiers and filters before and decided that to build a simple crystal radio would be a logical step further. I wanted to build a crystal radio for…
Aleksander Alekseev - R2AUK
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