This is just a heads up, but I got a couple of air core inductors made by SJ Andrews http://sjandrews.co.za, all measure perfectly (8mH, 4mH, 1.5mH, and 0.25mH).
I dealt with Kelvin and he managed to dig up a calculator for the inductors. Be patient! It's not going to make him a millionaire, but he is hobbyist and DIY friendly.
Also be warned that they are wound on standard bobbins, so they can end up a little big.
In terms of pricing, they're not bargain basement pricing, but they are certainly cheaper than an import + shipping. They are certainly not cheaper than winding your own, I normally do that, but the 8 and 4 weren't worth the PT.
I dealt with Kelvin and he managed to dig up a calculator for the inductors. Be patient! It's not going to make him a millionaire, but he is hobbyist and DIY friendly.
Also be warned that they are wound on standard bobbins, so they can end up a little big.
In terms of pricing, they're not bargain basement pricing, but they are certainly cheaper than an import + shipping. They are certainly not cheaper than winding your own, I normally do that, but the 8 and 4 weren't worth the PT.