Using the SDR-IQ and SDR-14 Software Defined Receivers as a Panoramic Adapter with the Yaesu FT-2000(D) Radio

Transcription

1 Using the SDR-IQ and SDR-14 Software Defined Receivers as a Panoramic Adapter with the Yaesu FT-2000(D) Radio 10/27/2008 Preliminary v1.0 The RFSPACE SDR-IQ and SDR-14 receivers offer leading edge spectrum analysis. When interfaced with a radio like the FT-2000, the panoramic display capabilities outperform the DMU-2000 in both resolution and update speed. In addition, the SDRs add an additional pair of demodulators and recording capabilities of up to 190 KHz of spectrum. There are two different methods that can be used to interface the FT-2000 to the RFSPACE SDRs: 1. The SDR-IQ/14 can be connected to the RX ANT OUT terminal of the FT This output has the signal from the antenna during receive. In order to feed both the FT-2000 and the RFSPACE SDR with signal, a splitter needs to be used. The RX ANT OUT signal is split in two. Half of the signal is fed to the RX ANT IN and half of the signal is fed to the SDR-IQ/14. This way both radios have an identical copy of the signal. The SpectraVue software needs to be configured to HF track the SDR to the FT In this mode, the SDR-IQ/14 will only be able to track up to 30 MHz. As the VFO on the FT-2000 is tuned, the SDR will follow.

2 2. The RFSPACE SDRs can also be connected to the FT-2000 IF output. This method works at all frequencies and it offers monitoring of both transmit and receive signals. This method requires taping the IF from inside the radio and down converting it to a frequency that the SDR-IQ/14 can tune to. Fortunately, the FT-2000 has easy access to the IF signal since this is used by the scope in the DMU-2000 option. The DMU-2000 Scope option in the FT-2000 requires two signals to be able to operate. The first signal is the IF centered at MHz taken before the IF roofing filters. The second signal is the reference oscillator signal that is used as a reference signal in the scope unit PLL. Both of these signals are routed using coax cables to the Scope unit (when present). When the optional Scope unit is not present, the coax carrying the IF signal is terminated with a resistor in the second receiver module (RX-2) as shown below:

3 The IF cable H can be unplugged and used as the IF signal since it is not going anywhere else. The RX-2 unit does not require this signal. The IF signal can also be taken from the connector on the other end of cable H. This connector is located on the bottom side of the radio and it is marked Scope: This picture shows where we added a tan colored coax to the connector labeled scope in the middle of the MAIN unit. The coax is routed to the other side of the radio and it then exits though one of the vent holes. It has a BNC connector on the other end. When plugging into this connector, the cable marked H can be left floating below the big metal shield. It does not need to be insulated since it is terminated on the RX-2 board

4 One way of extracting the IF signal without modifying the radio or requiring the special connector is to send the IF signal out the transverter connector on the back of the radio. To do this, disconnect cable H from the RX-2 board and plug it into the TRV (M) connector on the main unit as seen here:

5 The end of transverter cable M that was disconnected from connector M will have to be insulated with tape. The IF signal will be present on the transverter RCA connector on the back of the radio. Once the IF of the FT-2000 is extracted, it will have to be downconverted to the HF band. This can be done many different ways. For the Youtube video that we did : The IF of MHz was converted to MHz using a 80 MHz oscillator and a mixer. Any 5 volt computer oscillator can be used. It is coupled into the mixer with a 1000nH chip inductor and a series tuning cap. An MMIC with about 15 db of gain can be used between the mixer and the IF input. A schematic will be added in the next revision of this document. The latest version will be in the files section of the SDR-IQ and SDR-14 yahoo groups.