On Sat, 05 Feb 2005 09:14:37 -0500, Ken wrote:

Concerning the loopstick RX antenna identified as "VLF to Longwave:
Wideband Tuner" shown at:
http://www.stormwise.com/widetune.htm

I was told that the tap at 10% was to provide a match for a receiver
expecting a 50-ohm antenna.

Would I achieve the same result by using 405 turns, no tap, and a 9:1
current balun?

I am building a tuning cap box that covers from 25pF to 2uF in 25pF
increments. I am hoping to cover from 9kHz to 30mHz using the
variable capacitor box and 1,000 turns, with intermediate taps at 10,
33, 100, and 333 turns -- to be used as appropriate for each band.

Hi Ken,

I wasn't sure if your 30mHz was meant to be milliHertz or not, but
given the focus found at your link above, I presume you seek to listen
at the ELF and below.

When I looked at the truly meager coil offered at that site, I took up
my pen (metaphorically) to suggest you need something very, very, very
much bigger. 450 turns is truly pathetic. Some years ago, Scientific
American's column described a project that required 10000 to 20000
turns on a three foot ferrite rod.

However, none of this actually responds to your question about a 9:1
BalUn (and a current BalUn no less). This is waaaaaay out of the
common. (Read this will not be found off-the-shelf except at a
specialty store.) At these frequencies, standard transformer design
is suitable to design and construction details. Your stated need for
it to be a current BalUn would suggest your need for isolation.
Consider that those leads will need at least 3X and preferably 10X the
impedance observed in the coil you construct if that is what you are
trying to isolate. This means 50000 to 100000 turns of a wire pair
around a similarly long ferrite. Do you have the patience? ;-)

73's
Richard Clark, KB7QHC