OK this is easy,
A L = nH/N^2.
milli, micro, nano, 9 places...
A L = 1,000,000,000 (H/N^2) (converted my units to Henries)
Pats Inductor:
876 uH = .000876 Henries (converted Pat into Henry, sorry Pat)
and he used 100 turns to get that value,
we now have ditched the pesky units:
Al = 1,000,000,000 (.000876/100^2)
A L = 1,000,000,000 (.000876/10,000)
bring out the 10,000 so we can divide:
A L = 1,000,000,000/10,000 * (.000876)
A L = 100,000 * .000876 = 87.6 Bingo!
That is our A L number.
Now we can get turns:
30 mH = 585 turns
50 mH = 756
80 mH = 956
100 mH = 1069
150 mH = 1308
So thats the way it was back then, there best audio band powder core could do 87.6.
Now days that number is a joke.
But the 87.6 can also be used in a Ham Radio, it is so fast, those small, light di poles all bundled up in epoxy...