Joerg wrote:
Joel Koltner wrote:
Are there some vendors of readily available (stock) inductors that
have reasonably good Q's (100) throughout the HF band?

I'm familiar with something like the Coilcraft "maxi springs"
(http://coilcraft.com/maxi.cfm), and while they hit Q's of 100 by
30MHz, I'd really like something that's already there by 3MHz or less
(...and still have a self-resonant frequency of 30MHz). This seems
quite doable simply by making a larger coil with thicker wire, I'd
just like to find a place that offers such inductors off-the-shelf
rather than having to wind my own. Inductance in the ballpark of
1-10uH would be good, although it's not critical.

The goal here is to try out making some adjustable notch filters for a
receiver (by switching L's and C's in and out, like antenna tuners
do). Hence, high Q is important, but power handling capability isn't
so much, and anything smaller than a breadbox is fine size-wise.


There isn't much of a market for this stuff anymore, at least not since
the days of cloth-insulated wire :-)

Since it's for a receiver, how about building a Q-multiplier? Ok, many
youngster will scoff at that as being "archaic" but those things can
really rock.

I second that motion (since I'm not doing the work...).

I had thought of suggesting it, I should have done so.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html