An IF Based Panadapter for the FTDX-1200

Recently, I've been contacted by several individuals regarding my installation of an IF out connection for a Yaesu FTDX-1200, utilizing the G4HUP PAT board.  A key building block to achieve a working IF based SDR Panadapter.  Similar to a FTDX-9000 I previously modified, the FTDX-1200 does not come from Yaesu with a factory installed IF out jack.

Both the FTDX-9000 and the FTDX-1200 share the same IF frequency of 40.455 MHz. The correct G4HUP PAT board to purchase for the 1200 installation is the model PAT50M (G4HUP PAT board). If someone is not accustomed to working with small surface mount components. I highly recommend ordering the assembled version, and also an installation kit from Dave, G4HUP.  The installation kit contains all the parts necessary to install the PAT board into the transceiver.  Several individuals on the web, have directly tapped the IF on the FTDX-1200, without using the PAT board.  IMO they do so in a haphazard manner.  Directly tapping the IF, offers no protection or constant signal from the IF chain in your expensive transceiver.  I recommend the PAT board for reasons set forth in this article published in RadCom.

The addition of an IF out jack on the FTDX-1200 is not too difficult.  Unlike the FTDX-9000, it is not necessary to remove any circuit boards or dissemble the radio beyond removing the cabinet.  The installation is straight forward, and only requires a wire to be soldered between the PAT board to one leg of a relay, a wire soldered to a test point to provide DC power to the PAT board during receive, and a convenient ground connection to the PAT.  The last connections are the two ends of a length of Teflon coax between the PAT board and a rear mounted SMA socket.  All connections are made on the component side of the transceiver's main board.

First, remove both halves of the cabinet and set them aside. Next, I recommend that the chassis is carefully drilled, and prepared to receive the rear mounted SMA connector.  I found a convenient spot on the FTDX-1200 near one of the rear corners of the chassis.  However, before you mark the spot to drill the hole.  Ensure the planned location for the connector and hardware, will clear the circuit board, and any protrusions that are inside the chassis.  During drilling, it's handy to have a friend vacuum the loose aluminum shavings, to prevent them from accumulating inside the radio.

Once the chassis is prepped to accept the SMA connector.  I recommend to refrain from installing it until after the PAT board is installed, and the Teflon coax has been installed onto the SMA connector. It's just easier to attach the coax while the connector is on the bench.

The first connection between the PAT board and the radio is for the IF tap. The connection location in the FTDX-1200 is on relay RL1007.  A small wire will be soldered from Pin 3 on RL1007 to the PAT board. The PAT board is marked "IN" on one end. There are three solder pads on that end of the board. The pad in the center is where the IF TAP wire will be soldered to the PAT board.  Dave G4HUP, highly recommends using the small wire from the kit to make that connection, and to use double sided tape supplied in the kit to place the PAT board as close as possible to the IF connection in the radio. There are metal shields on the circuit board that are close to RL1007. The shields make a good solid base to secure the PAT board in the radio. Just ensure the PAT board will not short out against the shields. I found that using a thicker material (Velcro) worked just as well to secure the board. It also provides a bit of spacing between the shield and the PAT board to prevent any short circuits.

Location of RL1007 in the FTDX-1200 (white/grey cube)...

Component side board layout, showing tap point on RL1007.  The connection is made right to the third leg from the left on RL-1007 (facing the front of the radio).

The next connections are to provide DC power and DC ground to the PAT board.  Towards the bottom edge in the middle of the PAT board, there are two solder pads. The one closest to the bottom is for ground and the one above it is for DC power.

The technical supplement for the FTDX-1200, indicates there is an RX9 line that terminates on the main board at TP1002.  A connection to TP1002 will provide 9 volts DC to the PAT board during receive. The ground wire from the PAT board can be soldered to any convenient DC ground point.

Location Area of TP1002 on the main board...

Component side board layout, showing DC positive RX9 point on the main board (TP1002).  (Facing the front of the radio).

The final connections are made using the Teflon coax provided in the installation kit, between the PAT board "OUT" and the rear SMA connector. If not already done, solder the coax center conductor to the center pin of the SMA connector, and the shield to the outer body.  Install the SMA connector in the rear chassis hole that should have been previously prepared.  Carefully route the coax through the chassis up to the PAT board.

Leaving a generous amount of slack coax between the PAT board and the SMA connector. Cut the coax and solder the center conductor of the coax to the middle "OUT" solder pad on the PAT board, and the shield can be connected to either one of the solder pads above or below the center pad as shown below.

The PAT board installation should be complete. Double check all connections, and reassemble the radio. In regard to the SDR radio. Myself and several other hams I know, have had good experience using the RTL dongles from Nooelec. They seem to be higher quality than the run of the mill Ebay/Amazon RTL dongles.  I certainly have not experienced some of the issues and poor performance noted by others using the generic RTL 2832 devices available on Amazon and Ebay.

There is a kludge to tap the IF.  Rather than using the active buffer board with the filters, a small disc capacitor can be soldered to the same leg of the relay noted below. Some amateurs have tapped the IF that way. It's not something I prefer, because we lose the benefits of the buffer, but it will function and provide a signal to input into an SDR. I haven't heard of anyone sustaining any damage to their radio using the kludge, but proceed at your own risk.  A German amateur has the details on his QRZ page.

73 de AB4D.