These modifications of ancient Mobira radios are meant for licensed radio
amateur use.
In addition to this modification you also need the ham software
forthe radio.
If you don't know where to find it, tough luck...
These modifications are given as an example of a modification.
Your rig
may have different components, their tolerances may be somewhat different and so
on.
Please do not blame me if this doesn't work in your radio.
There are two screws under the display cover
and
one on the other side under a plastic cap
Open
the handset carefully, take the microphone away from the upper part.
The
speaker leads are soldered to the circuit board - and glued to the eprom
If
your handset doesn't look like this after it has been opened, you've probably
broken it - or it is of different model...
Take
the eprom away. Use proper tools and do not bend the circuit board,
remember
there's an LCD on the other side...
Just
another picture, you can attach the PTT button
to the white connector - just
follow Juha's example.
TMN1's RX VCO modified to 23 cm the stub length is about 8 mm.
The
capasitor connected to the stub is changed to 1 pF (later I found out that 1.5
pF gives more stable oscillation)
On the next three pictures you'll see what happened.
The oscilloscope is
showing the Lock Detect signal (pin 7) from the MB87006.
After
the modification there is a perfect PLL lock at 1.241000 GHz
And
perfect lock at 1.299000 GHz
The
lock range is about 1230-1315 MHz in the room temperature.
© 2000 OH3NWQ (both the photos and the text)