On 7/15/2017 9:20 AM, Tom Osborne wrote:
I built 3 UNUN's for some EFHW antennas I plan to use. On 2 of them, I
used 1 FT-240 mix 43 core (will be running these as portable antennas on
LP) and one one of them I used 2 of the same cores.
#31 and #43 are poor choices for transformers that must handle power
because they are lossy -- that's why they work for common mode chokes.
#61 is a far better choice for a TX transformer -- much lower loss at
HF, which is why it's also lousy for chokes. #31 and #43 ARE just fine
for RX antenna transformers below 20M.
73, Jim K9YC
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|