EFHWA TRANSFORMER

Some tests with transformer for end fed half wave antenna, EFHWA.
2 turns primary + 150 pF, 16 turns secondary seems to be good for 40-10m
3 turns primary + 150 pF, 24 turns secondary is good for 80-20m

FT240-43

Primary : 2 t, 

Secondary : 16 t

LIGHT TWIST

C=150 pF              Rtest = 3,1 kΩ

     

3510 kHz	7029 kHz	10140 kHz	14016 kHz	18096 kHz	21054 kHz	24930 kHz	28041 kHz
SWR = 2,61	SWR = 1,33	SWR = 1,11	SWR = 1,28	SWR = 1,41	SWR = 1,39	SWR = 1,30	SWR = 1,44

FT240-43

Primary : 3 t, 

Secondary : 34 t

TIGHT TWIST

C=150 pF              Rtest = 3,1 kΩ

3510 kHz	7029 kHz	10140 kHz	14016 kHz	18096 kHz	21054 kHz	24930 kHz	28041 kHz
SWR =  1,57	SWR = 1,29	SWR = 1,33	SWR = 1,65	SWR = 2,46	SWR = 3,85	SWR = 7,14	SWR = 13,63

 

Construction of 40-10m transformer
The plastic box is G311 (IP65)
Ref Farnell 1094700 price< 8 €

Ready for real test with End Fed