- Yaesu FT-2000 Panadapter, using the Softrock 9 Lite, SDR receiver kit

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Status: Built in Dec 2008 - Feb 2009, currently in use
 
This project consists of the following elements:  
    • Softrock Lite 9.0 SDR receiver (see http://softrocksdr.wikispaces.com/ and http://www.wb5rvz.com/sdr/) slightly modified (trivial, nothing more than connecting to an already existing point on the circuit board) to provide an 4xLO output  to an external double balanced mixer.  The Softrock receive frequency (Lo) can be set at either 13.888 MHz (4 x Lo + Lo = 69440 MHz), or at 23.146 MHz (4 x Lo  - Lo = 69.440 MHz).  If you use the PE0FKO firmware (version 15.8+) to control the Si570 oscillator, it can be programmed with either of the above as a power-on startup frequency.

       
    • A double balanced mixer
    • An (almost) non-invasive Yaesu FT-2000 mod, a 20 - 30 dB preamplifier added, connecting to the 69.450 MHz IF output intended for the optional DMU-2000 unit.
    • Optional, based on the preamp mod above, an additional in-line preamp, appr 10-15 dB, for a total of 30 - 35dB before entering my extremely lossy double balanced mixer.  Object is to have just enough in-circuit gain to ensure that background noise level received by the Softrock receiver does increase by a noticeable margin (20dB on 80m) when a (decent, efficient) antenna is connected to the FT-2000.  I used an old adjustable gain TV antenna preamp that I found in my junkpile.

Below are some pictures relevant to this project:

 
My Softrock Lite 9.0 + XTALL receiver:
 

(click on picture to enlarge)

Note the unconnected BNC connector in the picture below.  This one connects to header pin 4 on the larger of the two headers that mate the receiver and the Band Pass Filter together.  Pin 4 is connected to the Output of the Si570 oscillator, which runs at 4 times the Lo frequency of the receiver.  This can be used as an output in case you want to use the Si570 as a general purpose signal generator.  In my case, I feed this output directly, through a BNC connector,  to a double balanced mixer, to downconvert the Yaesu FT-2000 69.450 MHz IF to 13.88 or 23 MHz.
 
(click on picture to enlarge)
  
Here are the trivial mods done to the Yaesu FT-2000:
 
A Velleman kit, TV and FM Radio antenna preamplifier has been placed inside the FT-2000, in place of the optional DMU-2000 extension board.  It is held in place by two of the four screws that would normally hold the optional DMU-2000 extension board.  A cable normally parked in the secondary receiver board connector marked H (visible as being empty on picture) has been connected to the input of the preamplifier.  This connector H is just a parking connector in case the optional DMU-2000 extension board is not installed. 
(Note: These RG-174 type crimp connectors and jacks can be purchased from Spectrum Component Sales Inc, or scsiglobal(dot)com, the jack is part number
TMP-J01X-V6, and the matching connector is part number TMP-K01X-A1.  These are actually rather neat connectors, you find them used in most modern Amateur Radio Transceivers.  I bought 10 of each, for about $1.50 each.  Only one jack was used for this project)

(click on picture to enlarge)

Here is a picture of the output connection from the preamp, an unsightly cable with a FME type connector on its end sticking out of an air-venting grille on the back of the transceiver.  No new holes were drilled in my FT-2000D
 
(click on picture to enlarge)
Here is the most invasive part of the procedure.  A (yellow) lead was soldered to the unregulated input side of an 8V regulator, for 12V drive to the preamplifier.  The preamplifier probably uses way less than 10mA.
 
(click on picture to enlarge)


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