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Yaesu FT- 70G mods
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FT70G
The Yaesu FT-70G is a very rugged HF-SSB QRP tranceiver with a self-
contained Ni-Cd battery. This modification restores operation on 160
meters and improves receiver sensitivity between 50 KHz and 2MHz.
(It enables transmit operation between 1 and 2 MHz, but 2nd harmonic
attenuation will be very poor if used below 1.5 MHz.) The boards
are stenciled for the added parts, but this is no "clip the diode"
modification:
Low Pass Filter (LPF) Unit:
Add RL601 SPDT relay, 12Vdc (Yaesu p/n M1190066) I substituted a
Radio Shack 275-241 with little trouble. See note.
" RL-602 (same as above)
" C601 0.022uF,50V,ceramic
" C602 560pF,50V,ceramic
" C603 390pF,50V,ceramic
" C604 620pF,50V,ceramic
" C605 2200pF,50V,mylar
" C606 220pF,50V,ceramic
" C607 560pF,50V,ceramic
" C608 680pF,50V,ceramic
" C609 0.01uF,50V,ceramic
" L601 29T of #26 enameled on Amidon T37-2 iron powder torroid
" L602 26T of #26 enameled on Amidon T37-2 iron powder torroid
Note: The R/S relay has 2 pins connected to the wiper arm. Connect
only one to the non-grounded circuit board trace. The 2nd pin
on the Yaesu relay is a dummy pin and is soldered to the
board's ground plane for mechanical stability only.
RF/IF Unit:
Remove R26 470 Ohm,.25 W
" R25 4.7 KOhm,.25W
Replace R25 with a 470pF ceramic capacitor
Reg/Cntrl Unit:
Remove jumper C-A
Add jumper B-C
" D601 1N914
" C601 0.022uF,50V,ceramic
" Q601 2SC1959Y (SK9229/ECG85)
" R601 18 KOhm,.25W
" R602 39 KOhm,.25W
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