On 11/10/2015 9:12 AM, amdx wrote:
On 11/10/2015 1:41 AM, rickman wrote:
On 11/9/2015 12:08 PM, amdx wrote:


The silver is simply optimization. If you can make your coil wire 5%
bigger, you should have already done that. Then if you want to optimized
1 + 0.05, silver plate it.

Why can't you make the wire 5% bigger again? Where exactly is the cost?

You can.
I don't think ultimate optimizing is for you.
Just make your coil with as much surface area as room will allow.
Then know it could have just a tiny bit less loss if you had the silver.
That tiny bit of loss will not be noticed in use, except for that little
nagging thought...

I once had a 6 or 7 turn loop made with 1/4" copper tubing*, Q was about
800 at 1MHz. I could have made it with 1/2" tubing, probably would have
had higher Q.
I guess the limits are money and how you want to limit physical size and
maximum inductance you can use. Did I miss any?

People seem to go nuts with ideas that you need to optimize every little
thing without any evidence to show the significance of the impact on
performance. Your example is perfect. Increasing the copper tube from
1/4 inch to even just 3/8 inch would more than make up for silver
plating and not really cost that much more. There are guys who talk
about using single piece, 3 inch copper tube bent into a loop to avoid
having solder joints when using straight pieces even though those solder
joints will be about the same resistance as a quarter inch of the tube
or a microscopic increase in the resistance. Then they conveniently
forget about the resistance of the clamp connection to the vacuum
variable capacitor swamping out the solder joint resistance even more.

It makes me want to scream, "Enough of the maddness"!

--

Rick