Makeshift Square Loop Antenna for a Crystal Radio
 

A heavy 2 m x 2 m floor-standing wooden showcase in the shack appeared to be suitable as a frame for a crystal radio loop antenna. As luck would have it, the lone 20 km distant 612 kHz, 200 kW AM broadcast station being in the end-on position by default, there would be no need to move the unit. The counter top would make it quite convenient to sit down and carry out the testing.

The 5 turn loop was easily wound using about 42 m of ordinary hook-up wire.

The shack is relatively quite small to get a photo of the actual unit.

A representation of the same is attached.

It works quite well with my series/parallel-tuned crystal radios.

Further details at

https://nandustips.blogspot.com/2019...tal-radio.html

73,

Nandu.

Re: Makeshift Square Loop Antenna for a Crystal Radio
 

Hi Nandu,

You might also try a loop on the back of a large wardrobe door,
the main benefit being you can usually turn it through 180 degrees.

I use loops here too, as I have no space for outdoor antennas.

Kind regards
Dave G0ELJ

Re: Makeshift Square Loop Antenna for a Crystal Radio
 

That's a great idea OM Dave!

Many thanks.

73,

Nandu.

Re: Makeshift Square Loop Antenna for a Crystal Radio
 

Unless your wardrobes have sliding doors ;D

Re: Makeshift Square Loop Antenna for a Crystal Radio
 

Yes, of course, OM Terry :).

73,

Nandu.

Re: Makeshift Square Loop Antenna for a Crystal Radio
 

Broadside on, surely? ;D

Re: Makeshift Square Loop Antenna for a Crystal Radio
 

Hi Julie,

If it was broadside on, both sides of the loop would receive the
same phase? of the signal simultaneously, and this causes a null
in the signal.
This is why Direction finding loops are normally turned broadside on to
the beacons to obtain a bearing, as the null is very sharp, whereas the
maxima 90/270 degrees away are very broad (figure of 8 pattern).

Kind regards
Dave.

Re: Makeshift Square Loop Antenna for a Crystal Radio
 

Thank you for the explanation, Dave.

Regards,

Nandu.

Re: Makeshift Square Loop Antenna for a Crystal Radio
 

A good friend of mine has suggested pressing a colour TV degauss coil into service as a loop antenna (extracted from the TV, of course!). I don't know how practical this idea is...

Re: Makeshift Square Loop Antenna for a Crystal Radio
 

Hi Karen,

An old colour TV degauss coil would be about a metre in diameter and have around 50 turns.

I guess it would work, with the turns spaced out, at LF / VLF.

Regards,

Nandu.