Antenna for basic radio circuit.

Thread Starter

The_Logician

Joined Oct 2, 2023
12
Will insulated wire work as a good antenna or will my wire need to be exposed? Also should I directly put the antenna in the ground (literally) or a common terminal can act as ground (example a +15,0,-15 DC power supply's ground terminal)
 

Jerry-Hat-Trick

Joined Aug 31, 2022
551
I'm not an expert on radio, I'm sure others on this site are, but I believe an insulated wire is fine and a simple antenna should probably be 1/4 of a wavelength long (or a bit longer). And I don't think it should be "in the ground". It would help if you provided some detail, is this a receiver or transmitter? A schematic is essential to get helpful responses
 

Thread Starter

The_Logician

Joined Oct 2, 2023
12
Cat Whisker diode receiver.

Ron
Yeah my bad i wasn't specific enough. I'm making a Crystal radio reciever with a N34 diode instead of the crystal. Here's my circuit diagram. I'm trying to tune in to 792 kHz (the local AM station). So far I have had no luck. I was using a long wire as my antenna.One end was free and the other was at the ground that I used for all the others in the circuit. I'm using about 10 ft of wire so as pointed out above I think that may be the issue.
Can i use a length equivalent to a harmonic(1/4 of the wavelength is 94 metres so can I use say 1/16 th of the wavelength?)
 

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LowQCab

Joined Nov 6, 2012
4,053
Make your "Long-Wire" Antenna as long as possible, and, as high above the ground as possible.
Don't worry about an exact "tuned" length, more is better.

Lay out the Antenna so that it is in line with the Tower that You want to receive, if possible.

The Ground should be an actual Copper-Clad Grounding-Rod driven into the Ground.

A proper Lightening-Arrester is a really good idea for safety.
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Thread Starter

The_Logician

Joined Oct 2, 2023
12
Make your "Long-Wire" Antenna as long as possible, and, as high above the ground as possible.
Don't worry about an exact "tuned" length, more is better.

Lay out the Antenna so that it is in line with the Tower that You want to receive, if possible.

The Ground should be an actual Copper-Clad Grounding-Rod driven into the Ground.

A proper Lightening-Arrester is a really good idea for safety.
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.
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Also is it necessary to have it a straight wire or can arrange it in a zig zag pattern to fit more wire in a smaller space?
 

MrChips

Joined Oct 2, 2009
30,790
For a long wire antenna, you should hang 5-25m of wire horizontally as high as possible. The wire can be bare or insulated, single or multiple strand. If it is bare non-insulated wire, no part of the wire should touch any tree or building.

1704635524455.png

The ground connection should be made to a metal pipe buried in the ground. If you have cold water metal piping in the house, you can clamp a ground wire to the metal pipe.

1704635758945.png


The 1N34 diode should go to a resistor and capacitor to GND as shown.

1704635881906.png
 

LowQCab

Joined Nov 6, 2012
4,053
"Zig-Zagging" the Antenna probably won't improve Signal-Strength,
however, routing it in a giant "square" pattern may improve the number
of Stations that can be received from different directions.

Getting it as high as possible, and as long as possible, are the most important points.

Think BIG, and lots of SPACE.

Be careful with Water-Pipes,
most modern Homes have PVC-Plastic-Pipes underground,
which may change to metal-Pipes above ground.
These will NOT provide a workable Ground.
The Ground-Connection is fully HALF of your Antenna.
It's very important to have a very good Ground-Connection.
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Reloadron

Joined Jan 15, 2015
7,512
Yeah my bad i wasn't specific enough. I'm making a Crystal radio reciever with a N34 diode instead of the crystal. Here's my circuit diagram. I'm trying to tune in to 792 kHz (the local AM station). So far I have had no luck. I was using a long wire as my antenna.One end was free and the other was at the ground that I used for all the others in the circuit. I'm using about 10 ft of wire so as pointed out above I think that may be the issue.
Can i use a length equivalent to a harmonic(1/4 of the wavelength is 94 metres so can I use say 1/16 th of the wavelength?)
I had a feeling and during my much, much younger days the 1N34 germanium diode was my best friend. :) WHLI (Long Island) was a few miles from my long wire dipole antenna. A 1N34 as the detector and a pair of surplus Navy headphones was all I needed.

You want a long wire antenna and as long as you can make it. AM broadcast band is low frequency. Depending on distance and the AM radio signal strength you may be able to listen in less any amplification or tuning. Much like with an antenna, diode and headphones I could listen to my local AM station a few miles away. Well the transmitter site was a few miles away. Stay at it, you will get results. :)


Ron
 

Reloadron

Joined Jan 15, 2015
7,512
Worked fine for me and thanks as I should have included a cartoon of the circuit. :) Really depending on transmitter power and your distance from transmitting antenna with a good long wire antenna you should hear that local station.

Ron
 

MrChips

Joined Oct 2, 2009
30,790
One of my first present I received as a kid that launched me into studying physics was an induction coil.
We used to transmit Morse code to a pocket transistor radio with a spark gap generator similar to this.

1704643771521.png
 
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