Bandscope Modification Yaesu FT1000MP


Yaesu FT1000MP

In 2007 several SDR (Software Defined Radio) kits became available for Ham Radio purpose. Since most of these kits are just single band receivers, another easy solution was needed to benefit from the PC based Signal Processing on multiple bands. With the Yaesu FT1000MP, a full coverage short wave receiver was already available in the shack.  Why not reuse the already available hardware instead of spending money for a couple of additional monoband SDRs?

After studying the schematics of Yaesu’s FT1000MP it was decided to tap the IF (Intermediate Frequency) with an already available SDR-Kit.

This article documents the performed analysis and conducted work necessary to perform this modification.

Prerequisites

Please note that advanced soldering skills are necessary to perform this modification. SMD soldering equipment is recommended. If this “surgery” isn’t conducted with the necessary precaution, it’s an easy way to damage the transceiver seriously.

Please note that the author isn’t liable for  any damage caused as the result of attempting to carry out this modification! Although this modification was developed under best engineering practice, there still might be other or better alternatives available to tap an IF signal.

Analysis

The FT1000MP has two build in receivers, which work more or less independent of each other. In each of these receivers several filters can be found. Some of them are optional and can be selected from the front end, but there are a lot of internal filters in the IF which also have to be considered while searching for the perfect tap point.

Computer Soundboards are capable to handle an input spectrum up to 192kHz. Therefore the tapped signal should be as wide as possible.

The Main Receiver has three Intermediate Frequencies.

  1. IF on 70.455MHz
  2. IF on 8.125 MHz
  3. IF on 455kHz

In the technical description of the first mixer circuit the following section can be found:

FT1000MP Modification

Unfortunately, the crystal filters XF1001/1002 narrow the bandwidth to 12kHz for this and all following stages.

The Sub Receiver has only two Intermediate Frequencies:

  1. IF on 47.21MHz
  2. IF on 455kHz

In the technical description of the first mixer circuit the following section can be found:

FT1000MP Modification

At least the Sub Receiver offers theoretically a signal with 40kHz bandwidth at the output of the first mixer circuit.

Obviously due to the bigger bandwidth, the tap point will be in the circuits of the Sub Receiver.

Tap Point Selection

Below is a section of the Sub Receiver schematic with the first and the second mixer circuits.

SDR Modification

The following drawing shows a more detailed few of the second IF:

Yaesu FT1000MP Schematic

The wanted 455kHz signal can be found between the Mixer’s combiner (T8004) and the following splitter (T8005). The signal between T8004 and T8005 is directly connected to the Noise Blanker Circuit. Therefore a reasonable possibility is to tab the wanted signal at the Gate of the Noise Blanker Amp (Q8008).

The following drawing shows the Noiseblanker’s amp.

FT1000MP Tap Point

The signal will be tapped with a 100pF, directly connected to the gate of Q8008. The level can be adjusted with a potential divider (Trimm1 / R1). The following drawing shows how to tap the signal.

FT1000MP Tap Point schematic

Modification

The tap point is located on the RX2-Unit board. This board is mounted on the right side of the transceiver.

1. Unscrew and open the chassis

FT1000MP housing open

2. Unscrew the RX2-Unit board and disconnect the cables

The bottom side should look like this:

RX2 Unit FT1000MP

The FET Q8008 is located close to the lower central mounting hole.

Noiseblanker FT1000MP RX2

3. Connect the coupling capacitor C1 to the gate of Q8008
4. Connect Coax Cable to coupling capacitor C1

Detailed view SDR TapPoint RX2 board

5. Isolate PCB from bare wire

Tap point isolated on FT1000MP RX2 Board

6. cover all bare wires with adhesive tape

7. Reattach the PCB and fasten the screws
8. Reconnect all cables
9. Route the coaxial cable outside (I.e. through the amplifiers ventilation slots)

Please note, that the resistor (R1) and trimmer (Trimm1) have been installed on the PCB of the SDR.

In case an FT1000MP DC without internal power supply is used, an SDR can be installed internally. The following steps are optional.

10. Unscrew the fan

FT1000MP fan removal

11. Connect the SDR Power connection to the FT1000MPs power clamps

FT1000MP internal power clamps

It is recommended to fuse the SDR additionally

 

 

12. Reinstall the fan
13. Secure the SDR with double sided adhesive tape
14. Put a couple of windings of the Audio Cable (I/Q Signal) on a ferrite core
15. Route the audio Cable through the ventilation slots outside

FT1000MP with SDR

 

Rocky Screenshot with FT1000MP SDR Modification

 

Appendix

The SDR used is a 40m Softrock Clone sold by the German Ham-Radio Magazine “Funkamateur” (www.funkamateur.de).  The following modifications were made on the SDR:

l  The fixed frequency crystal was replaced with a tunable PLL circuit utilizing the CY27EE16 Chip from Cypress Semiconductors

l  PLL was tuned to 1,842 MHz (1,842 : 4 = 460,05kHz)

l  7MHz low pass input filter was removed

l  Level adjusting resistors (R1 / Trimm1) installed for the Low pass input filter

 

About Tobias (DH1TW)

Self-confessed Starbucks addict. Loves to travel around the globe. Enjoys the technical preparations of Amateur-Radio contests as much as the contests themselves. Engineer by nature. Entrepreneur. For more, follow him @DH1TW

Comments

  1. PAUL says:

    TKS for the very nice site… I make the IF 1000MP modification… run very well with a SDR-IQ RF SPACE and softrock 455khz.. 1822 xtal !

    I MAKE NOW some very pretty ” macro ” for mixwin and sdr+1000mp very fantastic for split operation..

    next splitter and filter from you ..

    73 and tks again… I pass your adress site to my freind JEFF F6AOJ AOJOURNAL..ON THE WEB…

  2. Hi Tobias,
    your idea is excellent,
    so my way with it is here :
    http://www.f6aoj.ao-journal.com/crbst_628.html

    Again congratulations and thanks
    73

    Jeff F6AOJ

    • Hey Jeff,
      thanks for the link to your webpage. I just checked it and I like the idea with the cinch plug at the back of the FT-1000MP. I can definitely recommend everyone to have a look to your side!

      73, Tobias

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