Hello.

I’m looking for some help and I only hope I can word this right so it makes sense…

Using the idea of a basic crystal set and mainly the LC circuit does anyone know of a calculator or an equation that will let me work out, if I know the value of the capacitor and the frequency I want to tune, what the value of the inductor would be and how many turns around a ferrite rod it would need to be?

Just an example… if C = 5 pf to 160 pf and the frequency is 530 kHz to 1610 kHz, how would I work out how many turns need to be in the coil to approximately tune that frequency.

Thank you in advance for any help you might be able to give.

Dawn.

P.S. I hope I’m posting in the right forum.

 

Hi,
This one of many Googled LC calculators.
http://www.deephaven.co.uk/lc.html

You may also find these links useful.

http://www.radio-electronics.com/inf...od_antenna.php
http://www.vintage-radio.net/forum/showthread.php?t=579
Eric
EDIT:
http://earlywireless.com/an_improved...set_design.htm

 

1/(2*PI*sqrt(L*C))

__________________
Nothing is impossible.
Once a problem is realised, the rest is just details

 

you need to have LC meter to measure the L value of the coil under preperation.
Incidentally for air core coils there is one called 'calcoil.exe'
you may download it and use it. perhaps it may call for a dll file which you have to find and place it. i use this to design the coils i make.

Sarma

 

Thanks all for commenting but I'm still left with one problem...

I have wound my own Ferrite Rod Aerial or Loopstick using 80 turns and it tunes the AM/MW band of 530 kHz to 1610 kHz using the 5 pf to 160 pf capacitor I mentioneded...

For the record the coil I made gives me a reading of 790 uH on my meter http://www.jaycar.com.au/productView...Max=&SUBCATID=

(That's the link to the DMM I own)

Anyway I ended up also testing some other Ferrite Rod Aerial or Loopstick's that I had sitting around and found that one that came from one shop had a reading of 1100 uH while a second one had a reading of 1160 uH.

I also ended up testing the Ferrite Rod Aerial from one of those brain box electronic kits and it only had a reading of 280 uH...

All these Ferrite Rod Aerial's when connected to my simple crystal set with the values as above still all turned the same stations, which left me a little confused.

I guess at this point I should mention I was trying to find the calculator or an equation so I could work out how many turns there should be in a coil to allow me to detect other bands such as shortwave, longwave and if possible FM.

Dawn.

 

Hi Dawny,

try to see the free e-book onrdaio on http://www.mikroe.com/en/books/rrbook/rrbook.htm they have given formulae and is useful- perhaps may doubts you may have will be cleared on a detailed study of this book

Sarma

 

Thanks again.