I bought 2 kits in the same order with both boards labeled V1.1, but the schematics both say V1.0 dated February 24, 2014. ?Both schematics specify detail for L3 and L4 in Chinese, but on the Internet I found a version in English. ?That version says L3 is an FT37-43 black toroid with 11 turns. ?L4 is a red T37-2 with 16 turns. ?Both kits supplied one red toroid and one green toroid. ?Winding 9 turns on a green core, I read 555 uH, so I rejected it! ?I happen to own a?batch?of?FT37-43s, so I substituted those for the green cores. ? I wound L3 with 11 turns to get about 36 uH. ?On the V3 schematic for the Frog Sounds 49er the inductor on the D882 collector was marked 22uH, so I removed turns to get to about 24 uH. ?With L3=24 uH and L4=1 uH, the receivers work in both 49ers, but not well. ?
The mIni Ring Core Calculator from DL5SWB says 11 turns on a red T37-2 should measure 484 nH and a red T50-2 would show about 1 uH. ?When I tested the supplied red core with 15 turns, I read about 1 uH on my L/C Meter IIB, so I am guessing it is really a T50-2, not a T37-2.
Neither transmitter works. ?Attempting to fix one, I first replaced the Q5 D882 with a BD139, but still no joy. ?Then I replaced Q6 and yet again, no deflection of the wattmeter. ?The boards are too small and lumpy to make good frisbees.
While I was mulling this mess over, I assembled a Frog Sounds 49er. ?Both receiver and transmitter tested fine in Froggy. ?Froggy transmitted nicely to a V1.1 49er and to a ham a couple of miles away. ?It appears to me that the antenna filters in both 49er versions are identical so that the L5 1 uH in Froggy should be the same value for L4 in the other version
So, my question is, does anyone know definitively what values I should use for L3 and L4? ?I have T50-2's and FT37-43s.
Thanks for any help whatsoever.
Bob KF6ABC Mix
