Here are a couple of simple calculations based on EZNEC predictions of
the impedance at the end of the G5RV ladderline - where the 1:1 balun
operates:
40m: Z = 27-j78
At the 1500W level, I = 7.5A rms and Vpk = 875v
30m: Z = 37 + j291
At the 1500W level, I = 6.4A rms and Vpk = 2,655v
Are we sure that the cables being recommended for the bifilar winding
can withstand those sorts of voltages? I'm not familiar with the US THNN
cable, but from what I see on Internet pages THNN #12 is rated at 600v.
Steve G3TXQ
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|