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Ten-Tec RX340

 

The RX340 is a professional 19 inch DSP receiver. Since its initial appearance in 2000 were various modifications made to its software and hardware. Mine is manufactured in 2005.

 

Most important features :
Frequency range : 50 kHz 30 MHz
Tuning steps: 1 Hz, 10 Hz, 100 Hz, 1 kHz, 5 kHz, 9 kHz, 10 kHz, 100 kHz, 1 MHz
(note that SWL-specific tuning steps were implemented)
Operating modes : AM, SAM, USB, LSB, ISB, CW, CW1, FM
DSP-filter bandwidth : 57
AGC : fast, medium, slow & programmable
Memory : 200
Very good large-signal behavior

The RX340 is, as with most professional receiver, hard to get. Although it is one of the few professional receiver that covers the requirements of the SWL. So is, thanks to the DSP, a notch-filter, pass-band tuning and a noise blanker available. The mechanical workmanship is good although a plastic adhesive film is put on the front which has the labeling for the various buttons. When comparing its front with a Telefunken or Racal is this a very cheap and sensitive front cover. But that was the only slip on the RX340. The RX340 can show off with its receiving quality. The receiver has such a large-signal behavior and quiet reception that it is hard not to fall for. But to use its full capabilities one has to operate the receiver with manual AGC so that it can show its reception performance.

I compared the receiver with the Reuter RDR50B, Telefunken E1501 & E1700. Its sensitivity is on the same level as the Telefunken receivers. But at very weak signals are the Telefunken ahead because of their clear sound. But there for do they have a stronger noise level! The RDR50B falls behind in this discipline. Very weak signals are not its strength. For the SWL is the synchronous detector (SAM) an important function. This allows a fading-free listening. But here goofed-up the RX340 big time!

The synchronous detector loses too quickly its synchronization when the signal gets a bit weaker. When the signal strength is above a specific level works the synchronous detector just fine. Absolutely clear reception. Noticeable is that the noise-blanker does not work in SAM mode. I suspect that the programming was not fully completely finished. Also hard to understand why the notch-filter is not available in AM mode. In SSB mode are all functions working. What also makes it a great receiver is the free-programmable AGC. The attack time, hang time and decay time can be individually set. This function is hard to find in other receivers. Working with the memory functions are easy and effective. The operating manual does not have first to be read.

Bottom line: the RX340 belongs in the top league! Its receiving quality is top-level. Possibly SDR receiver of the latest generation could be a bit better and more flexible. But these are no stand-alone receivers.

The RX340 is a wonderful receiver!

The RX340 Story below the pictures.

Written on 10 Nov. 2012

 

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For some who are interested in professional receivers may have noted the similarity between the Ten-Tec RX340 and the Watkins Johnson HF1000. This is no coincidence because both receivers had the same godfather. The godfather was a joint-development project of Ten-Tec & Watkins Johnson. What happened? The story goes back to 1991 when the NSA (National Security Agency) opened a project to develop the newest generation of receiver with a price tag below $10K.

 

At that time the market for governmental-military receivers was mainly dominated by Watkins Johnson, Racal and Cubic. And Ten-Tec wanted to join this group. So engineers from both companies worked together for a year to get the NSA specification below the $10K price tag. At the moment to present the NSA the newest generation receiver Watkins Johnson added a particular definition to the specification to their benefit and went their own way.

 

The newest specification stated that the equipment required a 20,000 hours MTBF (Mean Time Between Failure), which is commonly used for space electronics. Ten-Tec could not guarantee this at that time and was here with so-called pushed out of the business. This specification was absolutely no problem for Watkins Johnson as they already manufactured for years equipment according to military specifications. But Ten-Tec did not give up and built the RX330, a PC-controlled receiver, and went so their own way. The RX330 was a great success and was sold to many military agencies. The RX340 was the successor to the RX330, a DSP receiver with front user-interface.

 

 

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