A question About making RF Chokes

Bruce I have leftover chokes from the Big Talker SW project, but I don't know what values they are. To find out, I have to look. That seems hard to me because I'm not sure where to start.

Sometime soon I will get my act together and check. It would be my honor to mail you a choke if possible, provided the post office can keep it together until then.

If you are able to do that, It
would be great! But I don't
want you to feel as if you are
under any pressure.

I think the Post Office will still
be around. After all, what will
they do with all of those funny
looking square mail trucks?

Best Wishes and Thank you!

Bruce, DRS2

I may look for the chokes very soon now. Let me share a bunch of OT stuff.

Everyday I start fresh because sleep has a way of resetting the brain. So I begin laying out a plan including all the things that need doing. By the time there are more than three things, I start a review to see what can be post-poned. If everything can be post-poned, that's what I call being a big success.

However, after a few years nothing is done. So I need to do one or two things a month, minimum. This month I will look for those chokes, pending review.

Why not simply unwind 4/5 of the coil and you are at 20uh.

buy an l/c meter. they can be had for 50.00 and you can than custom make and check your coils then for 453.00 shipped that spec analyzer will look at your signal and harmonics.

to of the most invaluable pieces of gear to have when you are fabricating from scratch

I knew I had a leftover batch of chokes, but they are six(6) 1uH chokes.

If they were strung in series it would be 6uH.

But I'll look in some other places, just in case.

It was suggested that you unwind 4/5 ths of the coil but L is proportional to the square of the number of turns. So to unwind from 100 uH to 20 uH you would use 20 / 100 = N^2 or N = SQRT(.2) = .45 or about half the turns.

This is difficult to judge since the number of turns is not known. It would be better to start from scratch. Here's a calculator I have found useful for designing inductors: http://www.k7mem.150m.com/Electronic_Notebook/inductors/coildsgn.html#Alt_Form

or google for the Wheeler inductance equation. ETA here's a link: http://home.earthlink.net/~jimlux/hv/wheeler.htm

20 uH is going to be a bunch of turns so you may be better off buying the correct inductor.

Neil

How about this ...

http://www.coilcraft.com/apps/finder_apps/finder.cfm?mode=post&DropDown=L&Q=&quantity=1000&currency=USD&radio_mount=Either&acurrent=&acurrent_unit=amps&frequency=1&frequency_unit=mhz&dcr=&DCR_unit=ohms&L=20&L_unit=uh&srf=&SRF_unit=mhz&SubmitForm.x=87&SubmitForm.y=6&length=&length_unit=mm&width=&width_unit=mm&height=&height_unit=mm

Every one in a while, I feel like
we are all a "family" here, and
this is one of those times.

Thanks for your kindness.

Very best wishes,
Bruce, DRS2

On good days it's the best of family.

But just once in awhile it's like a family Thanksgiving dinner gone wrong.

Worst Thanksgiving I ever
had was in either 1982 or
1983.

It was real real bad.

A and of wandering drunk rock
musicians drove their tour bus
off the road and over our gazebo,
narrowly mising the bird bath.

(Sort of like what happened to RFB,
but instead of hitting his carrier
current station inside the house,
they drove over my friend's 1964
cherry apple red Corvair. Flat as
a pancake.) Then they saw my Part 15
station and proceded to go on the
air for two days. Heck! They turned
the transmitter power up to 101 mW
DC in. I was scared as hell.

Acually, that didn't happen at all, what
did happen was about 1,000,000 times worse.

But I had to get a goofy story in there
somehow!

Bruce, DRS2

Thank you god for not hitting the bird bath.

The drones will be searching 3-meter antennas.

I have a gigantic Tesla coil. When the
drone sees it, I'll catch it in my house
via a whole bunch of strategically mounted
automobile shock absorbers that I got
from a junk yard. (Mounted on the walls.)

All that metal will confuse the drone.

And, when it isn't looking, I'll trap it in
the washing machine.

Bruce, DRS2

Actually drones are RC devices, but are they part 15?

They transmit video back to a videogame parlor in Las Vegas, maybe we can monitor drone TV.

Auto shock absorbers might be the stuff new antennas are made out of.

Maybe I mean spring-shock-springs, which would form a helia-graphic, helimetric, halophone....... I can't think of the right word. A spiral, a DNA strand, a helix, a......a slinky toy, a.....