"Peter Bennett" wrote in message

are well into RF territory at 10 MHz, and will likely have to use
air-core coils in the tuned circuits.

Huh? Yes, he is well into RF and construction techniques will be different.
But while there are advantages to air-coil cores, their use in recievers
went out with hollow state detectors. Even in transmitters they tend to be
only used in the KW neighborhood anymore. I can't imagine that even in the
wilds of BC people are winding air coils and building on heavy steel
chassis.

...

"xpyttl" wrote in message
...
Huh? Yes, he is well into RF and construction techniques will be different.
But while there are advantages to air-coil cores, their use in recievers
went out with hollow state detectors.

I think that Coilcraft, API-Delavan, Pulse, etc. would be surprised to hear
them. Although I'd grant you that you don't typically find many air coils in
mass-market consumer electronics anymore, they're still used all over the
place in industrial and military design... where I work we buy tens of
thousands of the things every year for radio receivers!

Plenty of articles appearing in QEX and on-line also use air-core coils, since
it's a pretty fast and you can, of course, get whatever value you want with no
"minimum purchase" quantities.

---Joel Kolstad

What is the difference between air core coils and other kinds of coils?
Any advantages to using air core coils?
cuhulin

Hello Joel,


I think that Coilcraft, API-Delavan, Pulse, etc. would be surprised to hear
them. Although I'd grant you that you don't typically find many air coils in
mass-market consumer electronics anymore, they're still used all over the
place in industrial and military design... where I work we buy tens of
thousands of the things every year for radio receivers!


To imitate an old Volkswagen ad: Air doesn't saturate. Well, I guess it
does at some point but that's way past where ferrites and iron powders
do. Today many inductors in receivers are designed around iron powder
cores but when it comes to heavy-duty stuff air cores are the ticket.
Same for really high-Q tuning circuits.

Regards, Joerg

http://www.analogconsultants.com