The TEN-TEC RX-340 is a multi-mode, general coverage synthesized receiver utilizing extensive 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 short wave 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 analogue 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 analogue stages provide 1st , 2nd and 3rd I.F.s (and 80 dB of AGC) where signals then pass through analogue to digital converters. Everything else is accomplished in DSP including all mode detection, I.F. filters, AGC (remaining 40 dB), adjustable BFO, passband tuning and noise blanker.
An astounding 57 I.F. bandwidths from 100 Hz to 16 kHz are included. All filters have shape factor of 1.5:1 or better (6 to 60 dB). USB, LSB, ISB, CW, AM, Synchronous AM and FM are built-in. Four AGC modes are provided. Conventional Fast, Medium and Slow modes are familiar but the "Programmable" mode is groundbreaking. User may build their own personal AGC characteristic by selecting attack, hang and decay rates. Manual control from front panel is also adjustable over 120 dB range. A tunable Notch filter rejects unwanted signals in the passband. Receiver front end incorporates built-in preselector with eight ½ octave bandpass filters. Switchable 10 dB preamp and 15 dB attenuator are also provided. Signal strength meter is calibrated in both s-units and dBm.
Little known to most short wave listeners, TEN-TEC has been a supplier of commercial/government grade receivers for some years now. Our RX-331 was previously available only in a "black box" version for remote control. That model is used in government/military applications worldwide where multiple units run 24 hours/7days per week without interruption. RX-340 uses these field proven circuits (the PC boards are identical) brought together in acabinet with a comprehensive front panel. This provides conventional operation from the panel while retaining all of the remote control aspects of its’ predecessor. A built-in multi-drop RS-232 interface permits remote operation at baud rates from 75 to 38,400. Accessed from rear panel DB-25 connector, the interface can be configured for single or multiple receiver applications. The complete command language is published in the manual so enterprising users can write their own remote control software. 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 features fall into four categories: a scratchpad memory, 100 memory channels, memory scan and F1 to F2 scan. Each memory channel retains the frequency along with mode, I.F. bandwidth and BFO setting. Dwell time is programmable, Channel lockouts are provided and a Pause feature lets you interrupt scan momentarily. Squelch works in all modes and adjusts over a 150 dB range.
RX-340 has built-in TCVCXO to provide +/- 1 ppm frequency stability across the entire operating range of 0 to 50 degrees C. Audio is delivered to built-in speaker on the top panel, external speaker jack on rear and front panel headphone jack. Separate volume controls provided for speaker and headphone. Fixed level 600 ohm audio is also provided on rear panel. Front panel is a Lexan graphics overlay designed to last a lifetime. Chassis is aluminium with alodine plating on all parts to protect finish in less than ideal environments. Measuring 5.25"x19"x12.5"(HWD), RX-340 mounts in standard 19" (U3) rack and weighs 12.5 lbs.
Aerial 50 ohm, unbalanced, BNC connector. 2.5:1 VSWR max @ receiver's tuned frequency
Memories 100 memory store and recall
Passband tuning +/- 2kHz in USB, LSB & CW
Squelch all mode
Mute for use in transmit/receive applications, mutes audio and IF outputs. (revised 3/6/00)
PC interface Industry standard serial interface DB25 (RS232) connector, 3 wire hook-up
Audio line output 0 dBm (+/- 3 dBm) Two 600 ohm outputs (one for each sideband in ISB mode ) to DB-15 connector, ungrounded center tap. In all other modes, signal is mono. Terminals may be grounded or shorted together without damage. Two additional mono outputs are provided, one AC coupled, one DC coupled
Headphone output 1/4" (6.3mm) stereo phone jack. Stereo in ISB mode, switchable to LSB, USB or both. Mono in all other modes. 10 mw maximum into 600 ohms. Front panel volume control
Digital data output provides post DSP IF and audio information in both serial and parallel data streams
Power requirements a.c. 90V to 264V with frequency range of 48Hz to 440Hz (30 Watts nominal), IEC power lead supplied
Size (HWD) 133.3mm x 482.6mm x 317.5mm - 5.25"H x 19"W (3U), chassis depth 12.5" (including front panel knobs, handles and rear panel connectors )
Weight 5.675kg, 12.5 lbs