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RX-340 HF DSP Receiver

20.00 LBS
Calculated at checkout

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 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 RX-340 is a laboratory-quality instrument in its ability to quantify the amplitude and frequency characteristics of signals and receivers.

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 1st , 2nd and 3rd I.F.s (and 80 dB of AGC) where signals then pass through analog 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 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.

TEN-TEC has been 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/ 7 days a week without interruption. RX-340 uses these field proven circuits (the PC boards are identical) brought together in a new cabinet 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 aluminum with alodine plating on all parts to protect finish in less than ideal environments. Measuring 5.25“x19“x12.5”(HWD), RX-340 can be mounted in a standard 19” opening rack and weighs 12.5 lbs. One year warranty. Made in U.S.A.

RX-340 was recently endorsed by noted receiver design engineer, Dr. Ulrich L. Rohde, KA2WEU:

“In testing the RX-340, I find that this is the only affordable, totally DSP-based receiver where the digital AGC is as good, if not better than analog AGC systems. The intercept point for reasonable spacing is very impressive, better than +35 dBm in all cases.”

WorldStation, a sophisticated software package to operate the RX-340 under computer control, is now available from DXTra, Inc. Click here to access the DXTra website at www.dxtra.comDXTra, Inc. is a TEN-TEC authorized value-added reseller of TEN-TEC receiver products.

RX-340 Product Brochure

For Commercial purchase information please call Tom Salvetti at 304-884-7601 or feel free to email him at tom.salvetti@tentec.com.


FREQUENCY COVERAGE: 50kHz - 30 MHz at typical sensitivity. Tunable down to 0 MHz with degraded performance (see Sensitivity tables) MODE: USB, LSB, ISB, CW, AM, Synchronous AM, FM; all standard.


FREQUENCY STABILITY: using built-in TCVCXO, provides +/-1 PPM over entire operating range 0 - 50 degrees C.

ACCURACY: All internal oscillators are locked to either internal or external frequency standard.

EXTERNAL FREQUENCY REFERENCE: 1, 2, 5, or 10 MHz ( +/- 1 PPM, 200 mv p-p into high impedance load). Receiver automatically switches to this reference upon application, at power up or after any serial link activity.

SPURIOUS RESPONSES: All spurious less than -119 dBm equivalent input - preamp on.

IMAGE REJECTION: 90 dB typical, 80 dB minimum

BFO: Tunable in CW mode only, +/- 8 kHz. Tuning in 10 Hz steps. Fixed frequency in SSB/ISB, disabled in AM and FM.

SYNTHESIZER LOCK TIME: 10 msec typical

ANTENNA INPUT : 50 ohm, unbalanced, BNC connector. 2.5:1 VSWR max @ receiver's tuned frequency.

SELECTIVITY : 57 bandwidths selectable from .1 kHz - 16.0 kHz. Shape factor 1.5:1 or better. (6 to 60 dB) Bandwidth is fixed at 3.2 kHz in ISB mode, and at 4 kHz - 16 kHz in SAM mode. Minimum bandwidth is 600 Hz in FM mode.

GROUP DELAY : no more than .1 ms variation over passband of 300 Hz to 3050 Hz.

ULTIMATE REJECTION: 70 dB minimum regardless of filter selected. L.O.

PHASE NOISE: -120 dBc/Hz @ 20 kHz offset typical, -110 dBc/Hz maximum.

IF REJECTION: 90 dB typical, 80 dB minimum.

MEMORIES: 100 memory store and recall.

OPERATING TEMPERATURE RANGE : 0 - 50 degrees C @ full specification. -10 to 60 degrees C with degraded performance.



Mode BW SINAD Typical
dBm/uV Min
dBm/uV Typical
dBm/uV Min
AM (50% mod @400 Hz) 6.0 kHz 10 dB -103/1.6 -101/2.0 -112/.56 -108/.9
FM (6 kHz dev @ 1 kHz mod) 16.0 kHz 16 dB -102/1.8 -100/2.2 -108/.9 -104/1.4
USB/LSB/ISB 3.2 kHz 10 dB -112/.6 -107/.7 -119/.25 -115/.4
CW .3 kHz 16 dB -116/.35 -114/.45 -124/.14 -120/.22




CW @ 300 Hz BW
SINAD - 16 dB >500 kHz -116 dBm/.35 uV
100 kHz -115 dBm/.4 uV
50 kHz -114 dBm/.45 uV
20 kHz -107 dBm/1 uV
15 kHz -104 dBm/1.4 uV
10 kHz -94 dBm/4.5 uV
5 kHz -82 dBm/18 uV



Noise Figure (dB)
Typ Min

3rd Order Intercept (dBm)
Typ Min
10 dB PREAMP ON 10 14 20 15
PREAMP OFF 17 19 30 25
15 dB ATTEN 32 34 45 40

2nd ORDER INTERCEPT: 75 dBm typical, 60 minimum.

WIDEBAND OUTPUT, 1ST MIXER: 45.455 MHz center frequency

IF OUTPUT, POST DSP: 455 kHz center frequency, bandwidth determined by filter selection

SIGNAL MONITOR OUTPUT, DELAYED AGC: 455 kHz, 16 kHz bandwidth, AGC delayed 40 dB

SIGNAL MONITOR OUTPUT, 2ND MIXER, NO AGC: 455 kHz, 16 kHz bandwidth

AGC: Fast, medium, Slow, Programmable. Manual gain setting is provided in all four modes, adjustable over 120 dB range. DUMP feature provided in all modes.

MODE ATTACK (dB/ms) HANG (sec) DECAY (dB/sec.)
FAST 0.8 0 1200
MEDIUM 0.8 0 100
SLOW 0.8 0 25
PROGRAMMABLE 0.01-1.0 0.01-99.9 0.01-99.9

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" 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: 90-264 VAC, 48-440 Hz @ 30 watts nominal. Removable six foot line cord included.

DIMENSIONS: 5.25"H x 19"W (3U). Chassis depth 12.5" ( including front panel knobs, handles and rear panel connectors ).

WEIGHT: 12.5 lbs.


Squelch: all mode

Passband Tuning: +/- 2 kHz in USB, LSB and CW

Mute: for use in transmit/receive applications, mutes audio and IF outputs. (revised 3/6/00)

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Product Reviews

  1. Best receiver ever used

    Posted by Tom Shultz on 10th Dec 2013

    I'm retired government and have used a variety of high end receivers in my 37 year career. The RX 340 is the finest receiver I have ever owned; beats the nuts and bolts off my K3, Pro III, TS 870, and others. I have it connected to a rotatable Pixel 2B Loop at 35 feet and it is simply fantastic. Salute to Stan Brock (sales Ten Tec) for his advice and patience. Tom K2CIA.

  2. The RX340 reception quality is largely unmatched.

    Posted by Fernando Duarte on 10th Nov 2012

    The RX340 is, like most professional ones, rarely encountered. But he is one of the few professional tools that meets the needs of shortwave listeners. So, thanks to the "DSP", a notch filter, the band-pass tuning and a noise blanker available. The mechanical stability is good, wherein the front panel is covered with a self-adhesive film, on which the label is printed. Comparing this with the front of a Telefunken or Racal device, this is a very cheap and sensitive surface. But that was the grossest gaffe of RX340. Has the quality of reception for it in yourself! The RX340 can really convince. The receiver is hard and so high signal-noise, so that one begins to rave. However, in order to exploit the full potential, it must be driven with the RX340 manual receive reinforcement. Only we get the receipt results deal a feeling of surprise.

    I have compared it. RDR50B with Reuter, the Telefunken E1501 & E1700 The sensitivity of the RX340 is moderately related to the amount of the Telefunken devices. With the weakest signals to the turf, the Telefunken devices have the nose a little bit ahead because of its very bright playback. But they sound much more! The RDR50B falls in this discipline from something. Signals to the grass is not his forte. For the shortwave listener the synchronous detector (SAM) is an important function. This allows a fading largely outdoor listening pleasure. Unfortunately, the RX340 makes a small mistake here! The synchronous detector to quickly loses synchronization when the signal is weaker. If the signal is above a certain value, the effect of the synchronous detector is peak. Absolutely clean reception. Noticeable is that the noise blanker is not in SAM works. I suspect this is not well written. Incomprehensible, the notch filter is not available in AM. In SSB, but all functions are available. Which also contributes to a peak reception is the programmable AGC. These can be freely adjusted in the rise time, hold time, and in the fall time. Something is quite rare. The memory management is simple and effective. The instructions had to be taken not to hand.

    The bottom line may be said that the RX340 can compete with any other device! The reception quality is largely unmatched. Only the latest generation SDR devices could perhaps be a touch better and more flexible. But, these are not stand-alone devices.

    A dream receiver the RX340!


  3. A very good Shortwave Receiver

    Posted by Fernando Duarte on 24th Oct 2012

    I have the RX340 now a lot of weeks and can say that this Receiver are one of the best that I have purchased. But it are not perfect!Only one two things are not so good. The SAM are poor for this High End SW Receiver. By weak Signals it lose to fast the Synchronisaton. In AM and SAM if the AGC are Fast or Medium, the Sound have sometimes clicks. I think this come from the DSP. Very poor is, that the Notch Filter don't work on AM and SAM. Not acceptable for a High Class Receiver in this Price Range.
    The rest I can give only positive Feedbacks. For weakest Signals are the RX340 an excellent Receiver. If you work with the Manual Gain, they get a Reception almost without noise. Sensivity and Selectivity are nearly perfect.

    Best 73


  4. One of the best receiver I have used

    Posted by John Adams VK2XCQ on 1st Jun 2012

    Hi All

    The RX-340 is a special receiver.
    It can dig out a weak signal and can handle the local 200KW AM station without melting. Its strength and weakness is its flexibility, you need to understand what you are trying to do, to get the best from the 340. It is not for the beginner, it comes with no setting, it is up to you to work them out. If you spend the time it will reward you with excellent reception.

    I have many high end receivers, each has its own special area that makes it better than the others. The 340 is different it is very good in most areas, so it kind of wins against all the others. The 340 has the best received signal clarity of every radio I have ever listened to, what they send is what you get, no colouring at all to the audio. It blows away any thing I have heard for clarity. I can say that as a fact, if it is being sent in the transmission you will be able to hear it (as long as you have set your 340 correctly).

    RFI from the display is almost nil, you need to place a am radio 6 inches from the VFD before it is effected, and the rest of the box is RFI silent, excellent internal shielding really helps, this is great for a crowded desk. You try to use a AM radio any where near a SDR based radio or other LCD monitor display, all you get is the RFI from the display and or something from the hardware.

    Best of all it is a standalone unit, it does not need external computers or the internet to work, its software works, it is a rock solid box and mine has a nice thin wooden cover that looks nice and homely.

    The antenna needs to be good, just like any receiver, the better the antenna the better the reception.

    The Noise Blanker works on pulse noise, but not on other types of noise.

    My wish list that would make the 340 nearly perfect:
    It would be nice to have it work into the UHF bands.
    A noise reduction option.
    A self tracking heterodyne notch filter that works in all bandwidths and modes option.
    12v power option.
    A stepdown of the first IF output to 10MHz,so I can connect an external bandscope.
    An external bandscope option , like the one from elecraft.

    Oh Yea, if you do get a 340 , turn down the RF gain between 20 to 30.

    Hope this helps you decide to buy a RX-340.

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