I have been searching the catalogs for an 18nanohenry inductor to use in
conjunction with a Radiotronix RCR-433-RP Receiver and transmitter pair for
a remote control I am working on. Radiotronix has an app note that shows
this inductor used with a couple of 8.2pf caps to get good
reception/transmission for their modules.

I have been unable to find a source other than surface mount parts. Does
anyone know of a source for this size inductor, or know the formula that I
would use to wind my own?

I am posting this to rec.radio.amateur.homebrew and
rec.radio.amateur.antenna

TIA,

Joe
KB1KVI

On Thu, 30 Sep 2004 19:56:34 GMT, "Joe"
wrote:

I have been unable to find a source other than surface mount parts. Does
anyone know of a source for this size inductor, or know the formula that I
would use to wind my own?

"Wind" ?

As a rule of thumb, a thin wire has an inductance about 1 nH/mm, so a
straight wire about 18 mm long would have the required inductance. For
a thicker wire, about 25-30 mm straight wire would be required. Even a
single turn would increase the inductance quickly, so you would have
to shorten the wire considerably.

If 18 nH surface mount inductors exists, why not use them ? At least
the inductance would be much predictable.

Paul OH3LWR

"Paul Keinanen" wrote in message
...
On Thu, 30 Sep 2004 19:56:34 GMT, "Joe"
wrote:

I have been unable to find a source other than surface mount parts. Does
anyone know of a source for this size inductor, or know the formula that
I
would use to wind my own?

"Wind" ?

As a rule of thumb, a thin wire has an inductance about 1 nH/mm, so a
straight wire about 18 mm long would have the required inductance. For
a thicker wire, about 25-30 mm straight wire would be required. Even a
single turn would increase the inductance quickly, so you would have
to shorten the wire considerably.

If 18 nH surface mount inductors exists, why not use them ? At least
the inductance would be much predictable.

Paul OH3LWR


Thanks Paul,

What do you mean by a thin wire? #20 magnet wire, #26?

Sounds like I can make my own and very easily, with just a 18mm length of
(not sure what size) wire.

Joe
KB1KVI

That is one small inductor...