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5 votes
Accepted

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

I'll try to address your concerns a bit! I'll be simplifying here and there, but I think you'll notice where I'm doing that. I'll be doing my best to explain to him how this works. I understand ...
Marcus Müller's user avatar
5 votes

How do I get my crystal radio to receive?

This design of a crystal radio relies on the capacitance of the antenna and the inter-winding capacitance of the inductor as well as the inductance of the inductor to form the tuned circuit. The ...
Glenn W9IQ's user avatar
  • 18.6k
5 votes

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

Sea water is not that conductive: about 5 S/m. By comparison, the conductivity of copper is about 60000000 S/m, so seven orders of magnitude more conductive. The low conductivity of sea water will ...
Phil Frost - W8II's user avatar
4 votes
Accepted

What is an expected sensitivity of a crystal radio for 7 MHz band?

I notice you have a BNC antenna socket, so I wonder if you're having the same problem I once had. I built a crystal radio kit, attached it to my HF antenna, and got essentially nothing. I then ...
Kevin Reid AG6YO's user avatar
  • 24.7k
4 votes
Accepted

Multi-band Crystal Receiver?

A crystal radio generally consists of a simple LC network and a diode detector. So in theory, altering the LC network would allow you to tune higher frequencies. The real issue is that signals you ...
Glenn W9IQ's user avatar
  • 18.6k
3 votes

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

Congratulations on a nice home-brew project! I started my journey into amateur radio with a crystal set such as yours. Making the inductor (coil) out of copper tubing is overkill from an electrical ...
Glenn W9IQ's user avatar
  • 18.6k
3 votes

How do I get my crystal radio to receive?

I am no expert on House Wiring, but when mine was done, all the pipes in the house (central heating and water) were all grounded for safety reasons. I believe these were all connected to the main ...
Andrea Richards's user avatar
3 votes

How do I get my crystal radio to receive?

A bolt pushed into a pot full of dirt will never work! You need a ground return to planet earth itself for your crystal radio. :-) This could be as simple as the screw on a plastic cover that holds an ...
Mike Waters's user avatar
  • 8,071
2 votes

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

The use of 2.5 mm wire is enough, in a grounded rod at least 2 meters.
Denis Neves's user avatar
2 votes

Why does capacitive loose coupling increase selectivity?

I think if we were able to use perfect components, it would not matter. However, your antenna is not a perfect component. Is has many losses which result in a resistor R in its replacement diagram, in ...
ESP32's user avatar
  • 161
1 vote

trying to make a crystal radio, it doesn't work right

why can't I receive any other stations? why are L and C not what they should be? Strong stations likely drive the detecting diode beyond its square-law region: to the point where it acts as a ...
glen_geek's user avatar
  • 1,001
1 vote
Accepted

feasibility of wireless passive crystal earphones

A crystal radio is powered by the incoming signal. If you've ever listened to one, you'll know that the audio is quite faint, although a purpose-built transmitter could probably be made strong enough ...
rclocher3's user avatar
  • 9,242

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