RX-340 Review
 

 

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" Initial Report on Ten Tec 340 "

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"Donald Nelson's" August 2000 Initial Report on Ten Tec 340 receiver

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** Initial Report on Ten Tec 340 **

copyright 2000 by Donald Nelson
**This report is copyright 2000 by Donald Nelson. You are granted usage only if reproduction includes appropriate credit.

Disclaimer: This report is an initial assessment after three days of use on a dxpedition for purposes of logging both SW and MW Pacific stations from the coast of Washington. It represents a field test rather than a direct comparision of receiver performance specifications. Some of the findings I will hope are either easily corrected cockpit errors, or that firmware improvements will be made quickly to correct these minor deficiencies.

** Initial Assessment - Order and Arrival.**

As a HF1000A junkie, I was disappointed by the departure of WJ from the hobbyist receiver market. It is my personal experience that the combination of the HF1000A with the Sherwood Engineering SE-3 Delux will out-perform all other high end receivers I have tried (Collins 2050, Harris 590A, Cubic 3030B) for detection of faint DX (the remaining combination of R390A with SE-3 is yet to be tried by myself) including using extremely low gain, low noise antennas (Beverage, EWE, Pennant, Flag, K9AY). After overcoming my trepidation about ordering the first serial numbers of an expensive new receiver, I placed the order through Universal Radio.

When the receiver did not arrive as promised in April, I called and discussed the situation with TenTec’s VP of Engineering. He explained that this was not a case of birthing pains of a new product as the 340 is based upon the widely successful TT330 receiver supplied to key government agencies (NSA?). To build the 340, TenTec created a new front panel as well as adding some key features used by the hobbyist. The delay cited was due to the development of Synchronous AM and Passband Tuning.

**Arrival and Unpacking**

After the receiver did not arrive in June, I settled in for the “long wait”. I was surprised when Universal Radio called to tell me they would be shipping in mid July. After discussing the shipping delivery time, I arranged an upgrade to 2 day AIR to allow the receiver to arrive in time for a DXpedition to the coast of Washington with Guy Atkins and John Bryant. Targets for the weekend included weak Indonesians (300 Watt) as well as the usual Papua New Guinea targets, and a broad array of medium wave stations throughout the Pacific.

Upon arrival on my doorstep, I opened the box. None of the fancy foam and cardboard precision inserts found in WJ HF1000A boxes, which is disappointing if one intends to reuse the shipping materials to transport the receiver. The TT340 was swaddled in bubble wrap and simply floating inside the single layer cardboard box from TenTec.

What a beautiful front panel! I am in love with the simple layout (not unlike WJ) and the visually appealing meter calibrated in both S-units and dB. The lighter color of the front panel stands out significantly from the WJ’s - as seen in the attached picture of the listening setup while down at the beach this weekend.

Size, at 3 RU (rack units) high and standard rack width of 19 inches - is identical in front panel area to the HF1000A. However, the depth of the unit is only 2/3 of that of the HF1000A. Weight is listed at a mere 12.5 pounds, significantly down from the 22 pounds of the WJ. This means I finally have a premium receiver that can be adequately packed and carried onto an airline as cabin luggage. Popping the covers reveals that unlike the WJ, there isn’t a space inside the chasis suitable for carrying ones lunch and thermos of coffee .

The manual was a disappointment - early copywriter version. Yet a final copy is offered as an update when available to those that respond with their warranty cards. The manual does serve to adequately document most of the features. I found it vague in one area --- the “AF channel switch” which was only mentioned once under “4-6 Mode <- -> Buttons” and not so identified elsewhere on panel layout or in the manual. This turned out to reside under the Speaker audio gain knob as the LSB - ISB - USB button and indicators. It allows one to select the sideband with SAM (or ISB).

**Antenna Attachment and Initial comparision**

I attached the TT340 to my standard multicoupler arrangement (Stridsberg Engineering MCA-108 http://www.stridsberg.com/prod01.htm) for A-B comparisions against the HF1000A (w/SE-3) using the EWE antenna at my home. Both receivers have a simple BNC connector which in my opinion is far more reliable than the SO-259 connection seen on some receivers.

After noting that the manufacturer promises upgrades through swap of 3 IC’s (flash or eprom?), and that the panel region contains 2 switches labeled OPT-1 and OPT-2 (as yet not implemented), there is significant hope for future upgrades. This is especially important as Robert Sherwood reports finding a bug in the SSB DSP, and I have located a bug in the memory firmware.

Initial powerup - wow! The display is an amazing blue color, more pleasing to the eyes than the urine-green of the WJ under normal fully lighted room operation. Yet, with the room lights dimmed (typical of DXpedition late night operation), there is a definite harshness to the display when compared to the WJ. This could be corrected by TenTec by providing a dimming arrangement for the panel brightness (none found nor mentioned in the manual - hopefully an undocumented feature or perhaps planned?).

**Tuning Knob and Keypads**

The tuning knob feels great for a lightly-weighted knob - much nicer than WJ’s simple plastic tuning knob (wonder if I can buy spare knobs to retrofit my WJs?). Panel buttons and the smaller knobs have a positive response that tells you when you’ve activated them. I admit that I have a preference for the dished numeric keypad that sits above the front face of the WJ over the flat switches (not film switches) of the TT340.

Unfortunately for those of us that have become accustomed to the numeric keypad of the WJ as well as other premium receivers, the “0” and “.” keys are reversed from WJ. This leads to a bit of relearning and/or many bad entries of frequencies on the TT340 (for example, entering 2500 on the keypad yields 25 decimal decimal. I can only wish for a little future standardization in something so simple as a numeric keypad on communications receivers!

The manual clearly calls out that keypad can be used for entering auxiliary parameters and scan setup. It requires that you remember to enter the number then a sign (+,-). Reversing the order will merely change the frequency! I found this a bit disorienting until one gets used to it.

**SAM**

I am deeply in love with the Synchronous AM mode of the TT340 --- as a straight comparison between the two receivers (sans SE-3), the SAM of the TT340 has a much better sound quality through the phones (Senheiser and JRC ST-3). Neither receiver (currently) provides SAM PBT (passband tuning), although this feature can be had for both receivers through the addition of a Sherwood Engineering SE-3 Delux. A downside of the TT340 is that the minimum IF filter width for SAM is 4000 Hz while the WJ allows selectable SAM IF Bandwidth to a very small frequency. PBT, Notch (single frequency manual) filter, etc is disabled in SAM mode on the TT340 (PBT is promised at a later date). A plus for the TT340 in SAM is that it allows selection of Lower, Upper or both side-bands while in SAM, and SAM lock is shown by periods (S.A.M. instead of SAM when lock occurs). Sideband selection is poorly documented in the early manual (as “AF channel switch”) with the buttons located under the speaker volume on the front panel. On the WJ, a similar switch near the Speak volume controls only the speaker, not the headphones. An outstanding feature of the SAM mode is that the display shows S.A.M. when locked, and SAM when unlocked.

In ISB, the “AF Channel Switch” functions to select Lower, Upper or both side-bands for both phones and speaker (WJ allows only speaker). I found this usable a couple of times while listening to weak Indos such as Ngada (2899 kHz) and Mangarrai (2960.02 kHz) where the sidebands were differentially absorbed during the incredible solar storm of July 15-17.

In LSB/USB, I am overwhelmed by the 340’s ability to shift the PBT to achieve audibility. This feature proved awesome in recovery of reasonably strong 738 kHz (Tahiti) over the local USA AM stations on 740kHz with the TT340 (only use of the SE-3 on the WJ gave it the audio edge over the TT340 --- without this accessory the WJ is far behind the TT340 in LSB recovery of this signal). The 340 outperformed the WJ on the recovery of Fiji on 1467 Khz, but surprisingly did not hear as well as the WJ the weak signal of R. Western on 3305 kHz, nor the weak signal recovery of Ngada on 2899 kHz.

The PBT on USB operates as one expects --- + numbers are higher frequency and - numbers on the display are lower frequency. Unfortunately, the LSB is reversed from this, which leads to confusion for newbies as well as the need to remember which mode you are in while tuning. This is documented in the manual but does lead to confusion on the receiver --- this could easily(?) be reversed by TenTec in the firmware.

**Tuning Increments**

Both receivers allow the user to select a tuning rate. WJ allows either selection via decimal places or through an infinitely selectable randge (so you could decide to use 8.33 kHz as the tuning rate for whatever reason). Unfortunately the 340 allows only a limited set of 8 selections - 1, 10, 50, 100 Hz, 1,5,10,100kHz and 1 MHz. REMARKABLY the TenTec must not consider itself as capable of penetrating the foreign MW market as they have left out the obvious 9kHz tuning rate needed for foreign AM station spacing.(We use 10kHz here in North America). I am hoping that future microcode can fix this oversight.AGCAll of the four selections on WJ are programmable.

The TT340 has 3 fixed and one programmable – with the possibility of programming the attack, hang and delay. I found that the fast mode supplied by the 340 was adequate for the listening conditions I experienced. The TT340 also has a DUMP feature - which removes the AGC whenever it is pushed and held in. I had no occasion to utilize this feature although there could be a use with a weak signal buried within a very strong one.

**Memory functions**

Operated similarly to the WJ. Only difference is in storing options. I really appreciate the option to automatically find the next available slot (starting from 0). A downside was the number of buttons required to overwrite an existing channel - I had to push store - the channel number (2 digits) - and then store. Much simpler to be on the channel in the WJ and simply push store (as well as doing it the way described for the 340). Perhaps this exists on the 340 but I have not yet found it.The only bug I have located to date is in the memory storage --- I expect that it will store all the parameters set on the receiver. While it selects only a subset, it also selects the wrong value for the IF width. If I put the minimum for SAM in the receiver (4000 Hz), and store in memory, the memory location saves 6000 Hz. While this may be acceptable in some cases, it would cause a problem where signal spacing is only 5kHz.

My usage of the memories is through the use of the TUNE or SCROLL functions - both of which were adequate to scan through the Indonesian and Papua New Guinea frequencies during the Dxpedition (I located 23 different RRI transmitter sites and 17 different PNG transmitter sites using the 340. Similar results were found using the WJ. The only difference was a weak R Western that was not well resolved by the 340 in LSB, USB nor SAM modes)

**PC-based RS232 Remote Control**

I am a user of ERGO for controlling the HF1000As and 535D’s. I find this software to be outstanding for propagation prediction as well as the world map and use of the ILG (and self created) 232 port to control multiple receivers! If you are planning on setting up a multi-receiver listening post, you can control all the receivers without resorting to switching the 232 line or having multiple PCs.

There is another significant difference between the WJ and the 340 in the front panel disable when in remote control. The WJ can be toggled in and out of remote operation from the front panel. The manual for the 340 indicates that the front panel remote button cannot be used to take the receiver out of remote operation if the remote was entered through the RS232 control port! I use the remote disable on the front panel of the HF1000A to be able to offset the tuning while using the SE-3. I also wonder what happens to the 340 if the PC goes “bluescreen” while the receiver is in “remote”--- can the user override or must you reboot the PC operating system to reassert control? Something to try shortly!(of course, your version of Windows operating system never goes blue screen nor suffers from memory leaks, right?)

**Noise Blanker and Squelch**

Since the listening location was relatively quiet, I never had need to use the noise blanker (which of course did nothing for the normal tropical band noise found at frequencies less than 5000 kHz). Since I was Dxing and not program listening, Squelch was not used, although it was tried and found to work adequately (not a feature I will ever use )

**Use with an auxiliary DSP unit**

I use the Timewave DSP-599ZX to clean up a lot of the noise and heterodynes. This unit works very well using the headphones output of the WJ (avoids the issues with audio out of the “D-plug”. Using the 599ZX with the 340, I note that the audio phones output level is not great enough to match the input requirements of the 599ZX (fails to illuminate the light). I will have to see if some of the jumpers can be changed within the 599ZX --- as the user programmable gains were not sufficient. The output of the 599ZX was quite usable for both program listening and for driving several brands of Minidisk recorder.

**Use with an Sherwood SE-3 unit.**

Robert Sherwood assures me that the SE-3 as setup for the WJ (there is an internal gain adjustment) is quite adequate. I have found that the SE-3 works exceptionally well with the 340, just as it does with the WJ, to provide PBT using the SAM mode. The only advantage that the WJ has is that the SAM mode IF filtering can be reduced to the more usable 2.4 to 3.2 kHz that eliminates near-frequency interference.

Both receivers come with an BNC output of the 455kHz IF required to use the SE-3. In addition, the 340 offers an additional 3 BNC 455kHz with various combinations of AGC, etc. One of these is designed for the addition of a signal monitor (I’ll have to try my WJ signal monitor to see how this operates).

**OVERALL ASSESSMENT**

I am greatly impressed with this receiver - it is a significant advancement in the availability of “premium receivers” to the general hobbyist market. TenTec has had a good track record of upgrading the firmware for its Ham Radio (the Pegasus and Mark Fine (Fineware) to helped debug their remote control programs.)

**It’s a keeper!**

I expect that there will be significant interest amongst the aging population of enthusiasts that now have sufficient disposable income for the 4K pricepoint.

**I would like to thank TenTec for taking on this project in light of the recent departure of WJ from the market segment of high-end hobbyist commercial grade receivers.**


**This report is copyright 2000 by Donald Nelson. You are granted usage only if reproduction includes appropriate credit.