link coupling tuner

[NR5P]

I've read lots of info on here about making a link coupled tuner.  I have a coil on hand and was hoping it would be useful instead of shelling out doe on copper.  It is a 2.25 by 8" coil with about 60 turns.  I think it's 12 gauge wire.   Much much smaller than what people are making.  I was curious what downsides there would be to running a smaller diameter coil.  Also how would I calculate how many turns I should use or would this be a trial and error thing.

[Ed/KB1HYS]

If you can resonate the coil on the bands of interest you can use it as a tuner. 150pf cap and that coil would probably be ok-fine.
The Big copper tubing parts are good for QRO, with the size you're talking about, you'd be ok with 100w class rigs

Best thing is to try it!  the tuners are easy enough to build and your SWR meter will tell you enough about how good it is.

[Steve - WB3HUZ]

This should get you close.

http://www.mantaro.com/resources/impedance_calculator.htm#air_core_solenoid

[KX5JT]

If you need to calculate an AIR INDUCTOR this link is great!

http://www.k7mem.150m.com/Electronic_Notebook/inductors/coildsgn.html

[NR5P]

great links thanks, what about the primary though?(rig side of tuner)

[NR5P]

Oh and I'm using a 1000pf vac variable.  Just what I have on hand.  Its a russian surplus cap.  I used plexiglass to hold it and solid copper strapping to clamp to each side of the cap.  I'm gonna build a box that will set in the open window and use switches for the inductor and I got a turns counter for the vac variable at a hamfest which will work great.

[Ed/KB1HYS]

Wrap a few turns of heavy wire around the middle of the coil.  One end to center conductor, and run the shield to an alligator clip.  Tap the coil based on the band.  You can also put a series cap in there as well. but that's optional and might not be necessary.

use clip leads on the cap, and the open wire lines and you can configure it any way you want to achieve a match.  Versatile

[w4bfs]

don't forget insulated shaft coupling from vac var to turns counter unless you happen to like rf burns