Last updated December 28, 2005.
The Ten-Tec RX-320 is a HF DSP computer-controlled receiver. It is quite literally a "black box", with no knobs or traditional front panel. It lists for under $300 direct from Ten-Tec, and it's performance on HF rivals that of receivers costing up to $1000. I have a dozen other "serious" communications receivers in the shack, and was very pleasantly suprised by the RX-320's performance. It is a bargain if you don't mind the lack of a front panel. The recently introduced 320D model adds a 12 KHz IF output for use with Digital Radio Mondiale (DRM) software.
There have been many questions about the RX-320's performance on medium wave. There is a fixed filter which reduces the receiver sensitivity below 1 MHz, but I find there is plenty of sensitivity for dx listening. In fact, I normally use 10 to 20 dB of attenuation on the input of the RX-320 above 800 kHz to reduce overload from strong signals. This is with a 20 meter inverted-L antenna.
Ten-Tec should receive kudos for publishing the RS-232 and command sequence specifications. In addition to the Windows GUI control program provided with the receiver, the Ten-Tec web site provides a BASIC text mode control program (source code). The specs invite software innovators, and developers are taking up the challenge. As a Linux/Unix enthusiast, I have settled on DXTRA's WorldStation. This Java application is the only RX-320 control program that runs on Windows and Linux PCs and Sun workstations. [Note -- the latest version does not support Linux/Sun, but this may be changing in the near future.]
Another good Linux/Unix version is rx320. It uses the Xclass library routines to provide "windows-like" GUI components.
I recommend that you use an external antenna well removed from any computers, dimmers, or other noise sources.
Additional details, such as the latest RX-320 software, Programmer's Reference Guide, Schematic Diagrams and Material List are available from Ten-Tec's Web Site. In addition, there are details on their high-end $4K RX-340, $6K RX-400, RX-331, and RX-350 DSP receivers, and the Jupiter and Orion HF DSP transceivers.
Hardware Control Panel so that you can use the RX320 without a separate computer. They also make other PIC-based synthesizer for the Drake 4-series radios.
PDF of AMRAD LF/VLF Mods for the RX-320.
| Modes: | AM, LSB, USB, CW |
| Frequency Range: | 100 kHz - 30 MHz |
| Frequency Accuracy: | +/- 100 Hz at 25 degrees C |
| Memories: | Limted only by available RAM in PC, virtually any PC will store 1000's of stations |
| Sensitivity: | MODE B/W
AM (80% mod, 1 kHz) 6 kHz .64 µV, 12 dB S+N/N CW/SSB 2.5 kHz .3 µV, 10 dB S+N/N |
| Selectivity: | 34 bandwidths, 300 Hz to 8 kHz, 1.5:1 shape factor. |
| Third order intercept: | +10 dBm |
| Dynamic Range: | 90 dB @ 2.4 kHz bandwidth at 50 kHz spacing |
| IF Frequencies: | 1st IF 45 MHz, 2nd IF 455 kHz, 3rd IF 12 kHz |
| IF Rejection: | > 60 dB |
| Image Rejection: | > 60 dB |
| IF Output: | > Center frequency 12 kHz; bandwidth > 10 kHz; level approx. 2 V pk-pk into 600 ohms, sound card compatible. |
| Antenna: | 50 ohm unbalanced for external antenna. High impedance at telescoping whip connection, automatically switched out of line when external antenna connected. |
| PC Interface: | RS-232, DB-9, 1200 baud, 8 data bits, 1 stop, no parity |
| Connections: | +DC input, DB9 serial port, external antenna, line output, IF output, external speaker output |
| Power Required: | < 500 mA at 13.5-15 VDC (110 VAC wall wart supplied) |
| Audio: | external speaker: 1 watt at 4 ohms
line output: > 1 volt p-p into 600 ohms |
| Construction: | 2 epoxy glass PC boards, aluminum chassis, steel top and bottom |
| Size: | 3" high x 6.25" wide x 6.5" deep |
| Weight | 2.5 pounds (1.14 kg) |
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