back to longwire

1 building a 9-to-1 un-un:


There are lots of methods and guides for building a 9:1 UN-UN. Probably the easiest way is to just use some
#16 or so stranded wire in teflon jacket. I guess I'm a glutton for punishment, and went with #14 enameled
solid wire! I experimented with number of turns, and 5 seems optimal if you want to cover 6 through 160.
More turns might do better at 160 but you'll lose 6 immediately (too capacitive) an start eating into 10.

I use 3" OD solid iron cores, and I've had good luck with type K, 31, and 61 iron mixes. Wrap the core with
a few layers of electrical tape before you start winding, to protect the wire from the sharp edges on the
core. Wind three lengths of wire, 5 turns around and solder them together as shown so they form a single
long line. Feed the start and first turn, ground the start, and connect the far end to the contact for
your end-fed longwire.


2018.08 N0ZYC rev2 T240 core with #12 solid

2019.02.20 breajkfast share

schematics



last updated 08/12/2023 at 19:54:59