JA9MAT, Hidehiko-san's NS-40

Hidehiko has added a VXO and also is now driving his NS-40 With a DDS VFO.
He has graciously provided drawings and pictures of his mods for our benefit.
He indicates the VFO output needs to be at least 8 Volts P-P,
which is stepped up by the 1:2 transformer at the crystal socket.
For Reference, the normal output of his DDS VFO is 9.6 Vp-p at 7 Mc.
Thank you Hidehiko-san

Please scroll down to see his documentation and fine photographs.



VFO interface and VXO Schematic
Coil data is primary 5T : secondary 10T on an FT37-43 toridal core.
Output is connected into a .1 uF capacitor and the load is 200 ohm resistor.


VFO Interface Board
Output power is as follows;
Po=10W @ Vdd=14.52V (Dangerous!)
Po=7W @ Vdd=12.98V
Po=5W @ Vdd=10.9V
Po=3.5W @ Vdd=9.17V


VXO Switched in /Out with Header Jumper

VXO Plug In Crystal



Front Close Up

Side View


Wider View Front

Wider View


Nice Waveform At Crystal Socket

Homebrew Board Looks Etched


Internal View of Hidehiko's Beautifully Built DDS VFO

NS-40 and DDS


Hooked Up and Ready To Test

VXO and DDS Interface Boards


NS-40 and DDS

NS-40 and DDS


Internal View of Hidehiko's Beautifully Built DDS VFO

NS-40 and DDS


Front View

DDS Output Amp With Voltages