All I know is they used this in a certain amp that used a quantity of 12 M-2057
(modified 8908) tubes with an output of about 2000 watts PEP. The meter was
mounted within 4-5 inches of the output tank coil and was not shielded. The
meters I seen melt, but never the tape. The meter body looked to be made from
styrene plastic like plastic models are. It would be the same white plastic
they use now mostly on cheaper meters. This being the kind you can illuminate
with a lamp behind it. I couldn't say what the fibers were in the tape, but
they looked like maybe a glass type fiber, I'm not sure. The tape itself didn't
melt, neither did the fibers. I know the manufacturer just used tape that they
got the best deals on, so it could have been any composition. The tape they
used was about 1-1/2" wide, not the 3/4" stuff but they both should be the
same. I tried this with some 3M packing tape with the fibers, and it worked on
some I home brewed. I think a lot is how close the meter is t
o the tank circuit. On a tank coil using a toroid, I'm not sure but it may or
may not work. I have used it on smaller toroids handling 100 watts in input
matching circuits and it held up ok. On them though, the thinner the tape the
better as you fill up the hole and don't have space for the wire if you get it
too thick. The large toroids like used in the output tank wouldn't be bad as
the hole is a larger diameter. Ferrite toroids though supposed to be
electrically non-conductive and act like a ceramic. Iron powder though is
totally different. I've seen plenty of coils and RF transformers wrapped on
ferrite cores without any tape at all, and they lasted for the life of the amp.
Iron though uses an iron powder which is pressed under great pressure and heat
to make a toroid similar to the way they make powdered metal gears in
automobiles. It is conductive.
*********** REPLY SEPARATOR ***********
On 6/15/06 at 10:03 AM firstname.lastname@example.org wrote:
>Thanks to all who responded to my query about fiberglas tape.
>The consensus was that Scotch 27 is the thing to use.
>Other suggestions were for strapping tape (like for packages) which
>might work OK, but I don't know. Some of them have glass fibers but
>some have nylon or polyester fibers.
>Scotch 33 and 88 were also mentioned, but they are definitely NOT
>fiberglas tapes. They are high-quality black vinyl electrical tape.
>tnx agn es 73,
>George T. Daughters, K6GT
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