Topband: K2AV Folded Counterpoise- More Transformer Questions

[k3ky at radioprism.com]

I echo W1FMR's question regarding possibly substituting a T200-2 core.
Personally, I'd double it up, i.e. either a stack of two T-200-2 or else
a T200A-2 which is 1.00 inch thick vs. 0.55 in. for a T200-2. My guess
is that the power handling would be less than a T300A-2? But what about
smaller #2 cores for QRP? Provided you do choose combinations with the
same A sub L, you might expect similar winding inductances/ reactances?
I don't know about effects on Q here, but I suspect that is not an
issue? The A sub L for a stack of two T200-2 is almost identical to that
of a T300A-2.

My own question regards which exact types of enameled 14AWG wire might
be acceptable. I know the double polyimide type is very rugged with good
HV breakdown. OTOH there is so much insulation with those teflon sleeves
that I'd think it would be OK to use most any type of enameled 14 gage
wire? Or even bare wire? Would it make all that much difference in
overall HV breakdown ratings? Since this is a classical transformer, and
not a transmission line type transformer, I would think that the
characteristic impedance of the windings would matter less here?

What if the builder had on hand some 14 AWG silver stranded teflon wire.
That would also fit in the large teflon sleeving I have here, although a
little snugger. What might happen to the performance with that one
design change change to the wire type?

If I can get away with it, I may initially try a stack of T200-2 cores-
but if the bigger T300 size is truly essential, I'll get one on order.
BTW the most I'm usually outputting here is more like 800-1000 watts.
I'm sure the T300 size is a much better bet for a full 1.5KW.

73, David K3KY

P.S. I recognize that Guy would prefer to eliminate variability and
thereby accumulate some group experience among a user base.
Standardizing on the T300 type transformers would be a very good idea in
that regard. OTOH hams can be frugal, hams like to experiment, and hams
will often want to try to adapt designs to what they have on hand. There
is a natural tension between those two things.