Erich Kern wrote: > Merideth,, > > If you do layers, it's very important they don't come into physical contact > with each other. Some "bubble wrap" will do. > > Regards, > Erich > > Hi Erich and all, Yes, I plan to insulate between any layers, and thanks for the note in regard to it. One or more web sites suggest a insulating "spacer" of from 1/16 to 1/8", and, if using a ribbon type material, that it shouldn't be spiral wound, which could create a polarized effect of the shield itself. Actually alot of the "suggestions" per the web sites, and/or via this email are not really financially viable for myself. They are likely quite true and effective for shield purposes, but out of range for myself. Commercial sources are available but rather outrageous in their prices. Actually this particular approach is kind of a surplus yard route, but according to my brother Bob and his son, it can work....but each individual project is a "cut and try" gambit. I really doubt that I'll ever find a adequate sized container, ready made via any source, so the choice is really not available, outside of this approach. They have made many shields over a number of years using this kind of material, and combined they possess alot of electronics experience (not so for myself...ha) Regardless though, it will be interesting to try it out and see how effective it really is over time. Perhaps in the most positive aspect, (if it works as hoped for), it may offer a means for others to try, who can't really afford the standard route. However, even if does, just the finding, identification and use of this type material is probably also rather impossible for probably 99% of the people interested. The most common source is older torroid coil forms, which contain ribbon wound coils, which (hopefully) contain real permalloy. Most are small width, but the larger diameter/width ones are of course the most desireable. Another source could be "regular" rolls of the item which are not contained within thin aluminum, but they are even scarcer to find. Arnold Engineering seems to be the most prevalant brand (the coils are marked with a "ae......... and other letters. The last letter seems to designate its effectiveness, with a "a" as standard, and a "f" as being the best. Other brands exist of course, but aren't known as to their aspects. The usual color of the AE torroid cores are bright orange, but black has been noted in other brands. We'll see........ha. Take care, Meredith Lamb __________________________________________________________ Public Seismic Network Mailing List (PSN-L)
Larry Cochrane <cochrane@..............>