Note: these mods were found at various places on the Internet and
I'm just gathering them here - you should proceed with caution
before taking a soldering iron to your beloved FT-1000 ;-)
General Coverage Transmit Mod
Extended transmit frequency range for YAESU FT1000 -Remove top and
bottom covers. Remove top screw on each side which holds front panel
to chassis. Pivot front panel down slowly. CAUTION : if you let it go,
it will flop down rapidly and probably tear something loose.
Behind the meter will be the CNTL unit. It has a metal cover about
4 X 8 inches. Snap the cover off. Look to the top of the unit. You
will see JP-3. Remove the solder connection on JP-3.
The FT1000D comes equipped with additions including I.F. Filters for the
455khz. c.f. The narrowest of these has a 500hz. bandwidth, but no
matching filter for the 250hz. bandwidth for the 455khz. I.F. This
means that if you select the 250hz. bandwidth filter in the second I.F.,
it is paired with the 2.4khz. filter in the third I.F. It is a simple
modification to have the control section select the 500hz. filter in the
third I.F. instead. This modification requires the addition of a
switching diode (1N4148, 1N918 etc.) between the select line on the
250hz filter spot and the 500hz. filter. First access the filters on
the I.F. board, and clip the diode as indicated for the installation of
the 250hz. filter in the manual. Then remove the 500hz. filter, note
that the I.F. filter position for the 500hz. filter is the second from
the front of the radio. Then solder the diode between the cathode end
of the 250hz. select diode, and the cathode end of the diode under the
500hz. filter. This diode should be oriented with the cathode toward
the 250hz. select diode's cathode end. Now when the 250hz. third I.F.
control pulls the select line low, the new diode will pull the 500hz.
filter select line low, selecting that filter in place of the 2.4khz.
filter. When you finish this modification you will note that the 500hz.
filter reduces the wideband noise, and the "Width" control works when
the 250hz. filter is selected. Because of the mismatch in the filter
bandwidths, the first few detents on the width control act as an I.F.
shift, when the 500hz. filter is offset enough to "catch up" with the
bandwidth of the 250hz. filter, the action changes to a bandwidth
control. On my radio, the first three detents act as an I.F. shift, and
the next three reduce the bandwidth to under 100hz.
Subreceiver Antenna Switch Mod
One other change you may want to make to your FT-1000 is to add an
external antenna switch as suggested in the QST review of this radio.
This will be useful if you have the BPF-1 option. With this
modification you will be able to select the either the main antenna or
the BPF-1 antenna for the second receiver by using the front panel
switch. The switch added in this mod will allow you to select either
the main antenna or the antenna connected to the phono jack for the main
receiver, this is useful when using receive loops or converters. I
connect a Butternut HF-6V to the BPF-1 and my KLM LPDA to the main
receiver. I also plan to add a receiving loop for 80 and 160 connected
to the phono jack. This allows diversity reception by polarity,
frequency or mode.
In order to do this you must select the "E BPF" position on switch S1001
on the R.F. unit and add a switch between one end of S1001 and a pad on
J-1007. Remove the covers from the radio and access the R.F. Board as
in the manual for setting switch S1001. Remove the three screws holding
the connectors for the R.F. board to the rear panel, the six screws
holding the R.F. Board down, and unplug the three coaxial cables which
go to the R.F. Board. Remember where these cables were connected. Put
S1001 in the E-BPF (Enable BPF-1?) position. Lift the board so you can
access the bottom. Cut two twenty inch lengths of number 24 wire (or
smaller) and solder one end of one wire to the pad under S1001 opposite
the switch handle when it is in the E BPF position. Solder one end of
the other wire to the pad under J1007 which is near S1001, and is not
connected to the center of S1001. Route these two wires through the
hole near the center of the rear of the radio. These can then be
brought out through the grill on the rear of the radio. I mounted a
miniature SPDT switch in the grill, and connected the wires to it. When
these wires are shorted the main receiver is switched to the antenna on
the phono jack. Replace the screws and connectors, and try everything
out. You can then replace the covers.
Before implementing this mod, you should read Subreceiver Antenna
Modification elsewhere on this site.