The much-anticipated Ten-Tec Model 539 QRP transceiver and Model 418 100 watt amplifier are described in the following interview with Ten-Tec conducted by Tom Witherspoon, K4SWL, of QRPer.com. For those who are interested, the “Ten-Tec” in the following interview transcription is actually a collective of three gentlemen, namely,  Ten-Tec representatives Jack Burchfield (President of Ten-Tec), John Henry (Ten-Tec Software Engineer), and Stan Brock (Ten-Tec Sales/Marketing). 

Model 539 QRP transceiver

Frequency Coverage/Bands

QRPer: Will the 539 offer 160 meters? Some readers noticed that the Model 418 amplifier lists 160M as a feature, but the Model 539 doesn’t.
Ten-Tec: 160 Meters is a possibility on the Model 539, and Ten-Tec is looking into it.

QRPer: Could the 539 offer 6 meters at some point?
Ten-Tec: We doubt this will be included.

QRPer: How about 60M?
Ten-Tec: Probably not.

QRPer: One reader asked if ithe Model 539 would have the 0.5 to 1.6 MHz AM broadcast band. Is this a possibility?
Ten-Tec: Yes, though still to be determined, it may be possible to receive well into the AM broadcast band. The Model 539, of course, will be optimized for the ham radio bands, thus audio fidelity from an AM broadcaster will be somewhat compromised.

Pricing

QRPer: We know it’s early days, but what’s the target price for both the Model 539 and 418?
Ten-Tec: These are early days, indeed, but we believe the Model 539 transceiver will probably sell for less than $1000 US. As for the Model 418 Amplifier, pricing is yet to be determined.

Features

QRPer: Will the Model 539 have accessibility built in for the blind operator?
Ten-Tec: The Model 539 will be a computer controlled transceiver. Many of our visually impaired operators, use, for example, applications like Jaws to adapt our Ten-Tec gear for accessibility.

QRPer: Will the Model 539 have a built-in antenna tuner? Or as an option?
Ten-Tec: Due to size constraints, we currently have no plans for this option. Following the legacy of the early Argonaut transceivers, where simplicity and performance were key, we would not want to compromise the radio’s size to add a mediocre ATU.

QRPer: Will AGC also feature an “Off” position?
Ten-Tec: The Model 539 is a DSP-based transceiver, as such, there is no real “Off” position. This is really true on all HF DSP transceivers. The AGC function is a part of the DSP algorithm. With that said, if you turn down the RF gain far enough, it will act like a normal analog radio: it will not start AGCing until maybe S7 or S8. The Model 539 will have a selectable AGC with slow through fast speeds.

QRPer: So, will the Model 539 have RF as well as AF gain controls?
Ten-Tec: Yes.

QRPer: Will it offer front panel adjustable side tone for both frequency and volume?
Ten-Tec: Yes.

QRPer: Will it have user selectable tuning rates?
Ten-Tec: Yes.

QRPer: Will it have easy-to-set VFO A=B from front panel to work split?
Ten-Tec: Yes, just like all other Ten-Tec transceivers.

QRPer: Will the Model 539 have a keyer built in, and will it have memories?
Ten-Tec: Yes, it will have a built-in keyer, but no memories at this point.

QRPer: An attenuator? Available on the front panel?
Ten-Tec: You will have the ability to turn on or off a pre-amp. However, there will be no attenuator.

QRPer: That leads to my next question: one reader asked if the rig will have RF GAIN control rather than an ATTENUATOR, which is on the 516?
Ten-Tec: Yes, with our RF gain control.

I/O:

QRPer: Will the rig offer a line-level audio-out jack independent of the AF volume control?
Ten-Tec: Yes, the connector is the same as the Ten-Tec Eagle.

QRPer: Computer control port? Computer controllability?
Ten-Tec: Yes, the Model 539 will have a USB port for PC control.

QRPer: IF out to connect to SDR Rx for band scope use?
Ten-Tec: This is to be determined.

Modes:

QRPer: True FSK RTTY? Not forcing the use of AFSK.
Ten-Tec: There will be capability for a sound card device that can plug into the back for PSK and RTTY. At this point, it will be AFSK only.

QRPer: How about water resistance?
Ten-Tec: Let’s put it this way…if you get it wet, dry it off quickly!

Filters

QRPer: Good choices, even if they are extra cost plug-ins: Xtal and/or DSP?
Ten-Tec: This is the neat thing about this radio, Tom. This will be a reflection of the Eagle. We are going to give you a roofing filter in the first IF stage. There will be two additional slots for crystal filters. We will offer 6 kHz, 900 Hz, and if you want to, you could use filters from the Eagle as they have the same board. Additionally, it will have all of the DSP filtering the Eagle has. You’ll essentially have 3 roofing filter slots and over 100 DSP filters 100 Hz to 6 kHz in roughly 25 Hz steps for the first 120 or so.

QRPer: Will these be Ten-Tec proprietary, or may third-party filters (W4RT, etc.) be used?
Ten-Tec: Any third-party filter made to work with a Ten-Tec radio will work in the Model 539. The manufacturer would have to take the initiative to build the filter to match our radio. Inrad has a long tradition of working with Ten-Tec in this respect, for example.

Output Power

QRPer: How about easy power output control?
Ten-Tec: Yes. Selectable from 1 watt to 10 watts in 1 watt increments. Zero watts for CW practice.

QRPer: Can power adjust down to the QRPp milliwatt levels?
Ten-Tec: In its current state, the rig is 1-10 watts adjustable. That is something we could look at.

Performance

QRPer: Will the 539 be tested for RF immunity when used with portable (hfpack) type operation?
Ten-Tec: It is possible that these conditions could be mimicked during beta testing. We can say that all proper FCC immunity testing will be performed. Of course, it will meet or exceed all spurious emissions requirements.

QRPer: How is the rig cooled? Is it a fan that can be fully controlled, or is there a heat-sink–of substantial size to accommodate the rig when mated to the amp?
Ten-Tec: With the Model 539, heat is not a major issue. It will have a heat-sink, not a fan.

QRPer: Several readers emphasized the importance of minimizing the current drain on standby and receive. They felt this was the Achilles heel of the Argo V. Is this a consideration?
Ten-Tec: Current drain is a consideration, but we place the most emphasis in the following areas: performance, sound quality and ease of use. We will certainly take current drain into consideration, but will not compromise the radio’s performance in the process.

Availability/Distribution

QRPer: Would you consider distributing through HRO or AES?
Ten-Tec: Ten-Tec is a factory-direct retailer. We do, however, have two very unique ways to assist future customers who cannot easily drive to our retail/factory store here in Sevierville, TN. Firstly, we are unique in the industry in that we give buyers 30 full days after purchase to use our radios hooked up at their home, to their own system and antennas. If, for any reason, they are not satisfied, we will take the radio back and give them a full refund less the shipping charges. Secondly, we have a very active Ten-Tec Ambassador program with ambassadors in literally every state of the US. Simply contact an ambassador and they will help you in any way possible to get a feel for our radios. We know of no other manufacturers or retailers who offer these options.

Model 418 Amplifier Questions

QRPer: A QRPer would like the Model 418 to be easily interfaced with other QRP radios and kits with a drive level low in the one watt range. Is this possible?
Ten-Tec: This is a good point, and a strong point with the Model 418 amplifier. The Model 418 will be adaptable to any QRP transceiver out there.

QRPer: Will all modes be accommodated as well? (AM, CW, SSB, RTTY, PSK, FM), including those with full duty cycle?
Ten-Tec: Yes.

QRPer: For desktop use, one QRPer suggested TT could add the tuner into the amp, if there’s no room in the 539.
Ten-Tec: No, we would not put a tuner inside the amp.

QRPer: What are the minimum and maximum drive levels for the 418? One QRPer has a SDR project that will output 0.5 – 1.0 watts, but also would like to use it with a 516. Assuming that with the 539 output of 10w, it outputs 100w, but what might one get with one or two watts? Are there attenuators that could be switched out for this purpose?
Ten-Tec: Again, the Model 418 will work with any transceiver out there. You must keep in mind, though, that it will adhere to FCC regulations regarding amplifiers. As such, it cannot produce more than 15db gain. Five watts in will produce 100 watts out. If your transceiver produces more than 5W in—and that’s perfectly fine—the Model 418 attenuates, so that no more than 100 watts leave the amplifier.

General Questions

QRPer: In your view, how will the receiver compare to an Elecraft KX-1 or KX-3?
Ten-Tec: Honestly, we’re not comparing it to any radios out there. The Model 539 will be a Ten-Tec radio, as such it will be a performer, it will have excellent audio fidelity, and the Model 539 will be easy to use—at home or in the field. It is a continuation of the Argonaut legacy and has been in the works for quite some time.

QRPer: Finally, on the business side: Ten-Tec is successfully manufacturing in the US, keeping people employed in a profoundly strained economy while so much manufacturing has been relocated to Asia and the far east. How do you do it? How does Ten-Tec keep going, creating great technology instead of bending to these powerful economic pressures?
Ten-Tec: Let’s face it. These economic conditions are tough for any manufacturer and we’re certainly not immune to it. Though the amateur radio market is an active one for us, we also have military and commercial contracts. We also have an enclosure business. We’re well enough diversified that if one market suffers, we have business in other markets.

The Model 539 and the Model 418 will be designed, produced and manufactured here in Sevierville, Tennessee, in the US of A.

QRPer: Jack, John and Stan—I gathered these questions from hams who contacted me through QRPer.com and I also queried several email lists. I can say that there is a lot of excitement surrounding this radio—I sorted through and compiled these questions from literally a hundred or so. Thank you so much for allowing me to approach you with these questions and for your thorough answers.

Ten-Tec: Thank you, Tom, for the opportunity. This feedback is important and it’s our pleasure to provide it.

Post script

When I traveled last week to the Ten-Tec Hamfest in Sevierville, TN, and snapped a few photos of the Model 539 and 418, I had no idea that the response from my ensuing post on QRPer would receive the attention it did. It’s truly been extraordinary.  Immediately after making this post, questions about these two prototypes started piling up in my inbox.

I compiled these questions and approached several email lists to ask if they had questions. Again, the response was overwhelming.

I approached Ten-Tec with the landslide of inquiries. But, fortunately, Ten-Tec was up for the challenge, and I’m very grateful they were able to provide dedicated time to provide some answers.

While this remarkable rig cannot provide everything to everyone–and none can–my overall impression from the interview is that the Model 539 transceiver really will offer excellent performance characteristics at a reasonable price. Ten-Tec has proven with their Eagle, OMNI VII, and Orion series that the company is responsive to customer needs and updates firmware very readily.  This could be a winner.

I also came away from the interview with the strong sense that, though a lot of emphasis is now being placed on the Model 539, the Model 418 amp could be, in its class, the dark horse that finishes first.  Yet what would it run against? Indeed, I know of nothing else like it on the market. Speaking for myself, I have several QRP radios in both the shack and the pack that could certainly benefit from the extra watts it could provide, should conditions prove unfavorable during a rag chew.

You might just note that I’ll continue to keep in touch with Ten-Tec and provide any public updates here on QRPer.com. Please subscribe to our RSS feed or follow us on Twitter.

73/72,
Thomas
K4SWL