Crystal Radio with Air Core Coil

[vu2nan]

Accessible at

http://nandustips.blogspot.in/2015/07/crystal-radio-with-air-core-coil.html

73,

Nandu.

 

[C2]

I read that you can do a crude test of the winding form by placing it in the microwave oven on high for a few minutes. If it gets hot, it's not the best material.

 

[vu2nan]

I read that you can do a crude test of the winding form by placing it in the microwave oven on high for a few minutes. If it gets hot, it's not the best material.

Hi C2,
I suppose any non-magnetic, insulating material would be good enough for a receiver coil former.

Such tests would be more relevant for high power level / very high frequency applications.

Many thanks.

Regards,

Nandu.

 

[C2]

I think the competition x-tal DX-ers don't even like to use cardboard formers because they can absorb moisture.

"A PVC form can be used, but its dielectric has about 4-5 times the loss of the styrene form and will reduce Q, especially at the high end of the BC band."

http://www.bentongue.com/xtalset/26St4bXc/26St4bXS.html

PVC site:www.bentongue.com


I once used some gray plastic pipe that I think was bound with aluminum... (PEX?)

 

[vu2nan]

I think the competition x-tal DX-ers don't even like to use cardboard formers because they can absorb moisture.

"A PVC form can be used, but its dielectric has about 4-5 times the loss of the styrene form and will reduce Q, especially at the high end of the BC band."

http://www.bentongue.com/xtalset/26St4bXc/26St4bXS.html

PVC site:www.bentongue.com


I once used some gray plastic pipe that I think was bound with aluminum... (PEX?)

Hi C2,

With the lone 200 kW 612 kHz broadcast station just 20km away (as the crow flies), anything is okay in my location. At the same time there's no chance for DX.

But, in the case of a number of weaker stations being received, the coil Q would certainly make a difference.

Many thanks.

Regards,

Nandu.

 

[vu2nan]

Broken link rectified.

https://nandustips.blogspot.com/2015/07/parallel-tuned-air-core-coil-crystal.html

73,

Nandu.