Figure 1: PTRX-7300 CAD Model and Assembled Board
Figure 4: PTRX-7300 Block and Wiring Diagram
Figure 2: PTRX-7300 installed in ICOM-7300
Figure 3: Rear View of PTRX-7300 after installation
Amplifier circuit of panadapter also needs a DC power supply to operate. Best way to meet supply requirement is to find a connector carrying DC voltage inside the rig rather than using bulky external power supply. For this purpose we discovered that tuner connector designated as J331 is a good candidate on PA UNIT PCB. This connector is originally passed to back panel of the rig for external tuner connection via a cable assembly. We replaced this cable with a new one and passed tuner connector to the output panel again over panadapter PCB. DC power rails available on tuner connector are used as power supply of the amplifier. Amplifier only draws 30 mA current so doesn’t hurt tuner power rails which is capable of supplying more than one ampere current. Figure 4 is showing block and wiring diagram of panadapter.
Figure 5: PCB and Schematic pages of IC-7300 showing RF tapping point
The table below is showing comparison between PTRX-7300 and typical antenna signal switching/splitting/routing approaches.
After design and manufacturing period, PTRX-7300 is fistly tested and verified by appliying artificial signals and monitoring output on oscilloscope and spectrum analyzer. Also S-parameter measurements have been conducted in each port. Afterwards PTRX-7300 has been installed and tested in actual working conditions. As hardware RTL-SDR (HF), as software HDSDR and GQRX are used.
First tests were covering AM and DRM demodulation which intended to show high signal quality of the PTRX-7300. The last test was demonstrating another important feature which is synchronization of IC-7300 and SDR over CAT control. OmniRig free software is used with HDSDR.