Hello BITXers
I finish,last weekend, my BITX40 it works very fine...
I use beads for all trifilar coils, 10 turns 0.15mm diameter wire
twisted.
The VFO is a HiperVXO running with 3 parallel xtals of 3020kHz,
covering from 3010 to 2700kHZ (300kHz), the inductor series with xtal
and varible capacitor (2x140pF parallel) is a 10mm red head OM
oscillator. Look in my homepage at
The ladder filter are made with "CQ" Brand xtals and the values are
For CW a build a second BFO connected with a attenutor to the input
of the IF amplifier (just after the ladder filter) it is opereted
directly with the key (ground keying), I dont use a switch to change
from CW to DSB I disconnect the mike...
I put another switch to change from USB (trimmer to grond) to LSB
(inductor commercial 4.7?H series with a trimmer 4.6 -50pF yellow).
I will plan to make it a multi band ... then I make the 7MHZ filter
outside and this filter are build with 3 x 4.7?H commercial inductors
(looks like a 1/4W resistor) ....
The PA I will change to a bipolar 2SC1173 and it devellops about 9W
output... I build also a RF pre-amplifier thinking in others bands.
The LPF are also build in another box...
I made few QSOs CW and SSB with good reports,
I will make some pictures and discription ....
73 from Brasil
PY2OHH Miguel
