The TEN-TEC RX-340 combines cutting-edge, state-of-the art technology, with excellent ergonomics and esthetics. Digital signal processing (DSP) brings the performance and repeatability of expensive military grade communications receivers into the price range of top end commercial receivers for shortwave listeners. Tunable from 5 kHz to 30 MHz, it provides tuning steps and display resolution of 1 Hz. All three displays are blue-green vacuum fluorescent and provide unparalleled contrast and readability.
The performance level of receivers in this class is possible only through extensive use of Digital Signal Processing. These designs utilize fewer analog circuits than traditional receivers. Powerful, specialized DSP microprocessors replace many of the discrete circuits with intensive software containing over 60,000 lines of code. High dynamic range analog stages provide first, second and third IFs (and 80 dB of AGC) where signals then hit analog to digital converters. Everything else is accomplished in DSP including all mode detection, IF filters, AGC (remaining 40 dB), adjustable BFO, passband tuning and noise blanker. An astounding 57 bandwidths from 100 Hz to 16 kHz are included. All filters have a shape factor of 1.5:1 or better (6 to 60 dB). USB, LSB, ISB, CW, AM, Synchronous AM and FM modes are built-in. Four AGC modes are provided. Users will be familiar with conventional Fast, Medium and Slow modes, but the "Programmable" mode is ground breaking. Users may build their own personal AGC characteristic by selecting attack, hang and decay rates. Manual control from the front panel is also adjustable over 120 dB range. A tunable Notch filter rejects unwanted signals in the passband. The receive front-end incorporates a built-in preselector with eight one half octave bandpass filters. Switchable 10 dB preamp and 15 dB attenuator are also provided. The status of many programmable parameters are constantly shown on subdisplays. The signal strength meter is calibrated in both S-units and dBm.
Little known to most shortwave listeners, TEN-TEC has been a supplier of commercial grade receivers for several years. Their RX-331 "black box" is used in military, diplomatic and commercial concerns worldwide. In this application multiple units run 24 hours per day, seven days per week without interruption. The RX-340 uses these field proven circuits along with a comprehensive front panel. This provides conventional manual operation while retaining all of the remote control aspects of the RX-331. A built-in multi-drop RS-232 interface permits remote operation at baud rates from 75 to 38400. Accessed from the rear panel DB-25 connector, the interface may be configured for single or multiple receiver applications. The complete command language is published in the receiver's manual so enterprising users can write their own remote control software. The RX-340 also includes Built-in Test or "BITE". This self-test capability will identify virtually all faults to the board level.
Memory and Scan functions fall into four categories: a scratchpad memory, 100 memory channels, memory scan and sweep (F1 to F2 scan). Each memory channel retains the frequency, mode, IF bandwidth and BFO setting. When scanning memories, the dwell time, dead time and gaze time are all programmable. Channel lockouts are provided and a Pause feature lets you interrupt scan momentarily. The Squelch works in all modes and adjusts over a 150 dB range. And of course, keypad entry is supported. A dimmer function allows you to adjust the brightness of the digital displays.
The RX-340 features a built-in TCVCXO to provide ±1 ppm frequency stability across the entire operating range of 0 to 50 degrees C. Audio is delivered to a built-in speaker on the top panel, external speaker jack on the rear and the 1/4 inch headphone jack on the front. Separate volume controls are provided for the speaker and for the headphone. Fixed level 600 ohm audio is also provided on the rear panel. The front panel features a Lexan graphics overlay designed to last a lifetime. The chassis is aluminum with alodine plating on all parts to protect finish in less than ideal environments. A mute provision is provided for transmit/receive applications (mutes audio and IF outputs). BNC Outputs include: IF Output (post DSP 455 kHz bandwidth determined by filter), Signal Monitor Output (Delayed AGC, 455 kHz, 16 kHz) and Signal Monitor Output (2nd Mixer, No AGC, 455 kHz 16 kHz bandwidth). The RX-340 mounts in a standard 19 inch rack. Made in Tennessee, USA.
The Ten-Tec RX-340 was reviewed in the WRTH 2003 where it earned the coveted Best Professional Receiver Award.
1AVAILABILITY NOTE 03/14/17
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#0340 00-17 D4950/4250 Q1800/2400 US 01/18 _