The Pennant transformers sold by Lance Johnson and K1FZ both use the
Amidon FT140-43 core which was specifed in the July 2000 issue of QST.
Since then it has been found that the Amidon FT-140-77 core is a much
better choice. The SWR with the -43 core was about 3:1 to 4:1. Luis,
IV3PRK has found that if you use the -77 core that the SWR will be 1:1.
With the FT140-77 core, use 3 turns for the low-Z (50 ohm) winding and 13
turns for the high-Z (900 ohm) winding.
73, de Earl, K6SE
_______________________________________________
Topband mailing list
Topband@contesting.com
http://lists.contesting.com/mailman/listinfo/topband
|