Ten-Tec Jupiter: My faithful HF radio for a decade

My Ten-Tec Jupiter Model 538 HF Transceiver celebrated its 10th anniversary in my ham radio shack. I wrote a review of it for the May, 2001, issue of BARC’s Bark, the newsletter of the Boulder Amateur Radio Club. I include here that review verbatim as it shows my thoughts after having the radio for a couple months:

KEØOG Takes Leap to Software Defined Radio!

I’ve been operating the same HF radio for twelve years. My “old faithful” rig has been a Yaesu FT-747, originally designed as a very simple mobile HF rig. This great little radio has been my faithful companion for SSB, CW, AMTOR, PacTOR, PSK-31, and even shortwave listening. I’ve added a number of accessories, including an electronic keyer, a direct-entry keypad, an SWR meter, and a DSP audio filter. For the past five years or so, the rig has operated entirely from a solar power setup consisting of photovoltaic panels on the roof that charge a pair of large, deep-cycle batteries next to the rig.

So why upgrade? Well, the FT-747 is a pretty basic rig. Although it has a nice CW filter, I have to use the SSB filter for digital modes. There are no bells or whistles and, well, it was just time. I’ve been surveying the market for a few years and had pretty much settled on the Kenwood TS-570 [as of 2011, the TS-590S] when my eye caught the ad in the December QST for the new Ten Tec Jupiter. The Jupiter is the same radio as the Ten Tec Pegasus, which is a software-defined radio that operates strictly as an accessory to your PC (see the QST review of the Pegasus on page 63 in the February, 2000, issue). The exception is that the Pegasus has been “wrapped” in a package that allows it to operate as a stand-alone radio. I had been interested in the Pegasus, but did not like the idea of being tied to the PC for all operations. The Jupiter looked quite attractive. It has many features, including full control from the PC a la Pegasus, but has the ability to stand alone. The target market for the Jupiter matched my needs well–a mid-range HF rig with an excellent receiver, 100 watt transmitter, and excellent filters for a variety of operating modes. The fact that the Jupiter (like the Pegasus) is entirely software-defined was also attractive. That means that Ten Tec can upgrade the radio at any time. New capability is just a download away.

I had a major concern, however. That is my solar power supply. Since the new rig would have to operate from my battery supply, it would have to provide reliable communications at a range of voltages that would go from 12v to 14.4v (the higher voltage is the voltage in full sun). The Jupiter web site (www.tentec.com) said that the max voltage for the Jupiter was 14v. So, I sent an inquiry to Ten Tec explaining my situation. Scott Robbins, W4PA, the Ten Tec amateur product line manager, fielded my query. After a few e-mail exchanges, he offered to loan me a Jupiter to try out with my solar power supply! How could I turn down an offer like that?

A few e-mails later and the Jupiter was at my doorstep. The Jupiter looks like a cross between a radio and a computer. The usual array of knobs is present, but they’re labeled a bit differently. A reassuringly large tuning knob is placed prominently on the right. But there aren’t as many buttons as one might expect–that’s because many of the buttons that one normally sets and forgets are activated via menu functions. Three knobs that see extensive use are labeled “bandwidth” (actually a rotating selector to choose between 34 different bandwidths!), PBT for passband tuning, and the ever-useful “multi” knob. There is a series of buttons that determine the function of the multi knob. It can be, in turn, AF gain, RF gain, mic gain, power output, keyer speed for the built-in keyer, squelch level, monitor volume, or menu selector. That’s a mouthful! On the one hand it unclutters the front panel. On the other hand, there are times when I’d like to twiddle between the RF and AF gain controls a little faster without having to punch a button between.

The major feature of the front panel is a large (2-1/2″ x 4-1/2″) backlit LCD display. This display is home to every conceivable type of information, including frequency, mode, a simple spectrum scope, memory information, and the state of various buttons that can be pushed. One nice feature is that settings of the multi control are shown at the bottom of the screen both in graphical and numeric forms–it is now possible to set keyer speed to exactly 15 wpm, for example. The “meter” portion of the display provides signal strength both graphically and in numeric S-units–a nice touch! In transmit, you can choose between power and SWR. There’s a “tune” button that can be pressed to determine SWR. The Power output setting of the multi knob reads power numerically in watts–another nice touch.

The rig has all the features one would expect from a mid-priced radio. These include the ability to work “splits,” store frequencies in memory, VOX, RIT and XIT. The rig has a built-in ALC on transmit to keep the signal from splattering.

The DSP features are remarkable. Not only can the receiver bandwidth be set from 300 Hz all the way up to 8 KHz (sometimes useful for shortwave listening) but the SSB transmit audio bandwidth can be varied as well! The passband tuning control is available at the touch of a button. Holding the button down for a bit longer will reset the PBT back to zero (it does this on RIT and XIT as well). I found the PBT, coupled with the narrow 300Hz filter, to be very useful for honing in on a single PSK-31 signal. This takes some practice, but really helps pick a signal out of the mud.

The rig also includes an automatic notch feature as well as digital noise reduction. I found that the noise reduction feature will make weaker signals sound a bit “grainy” and is more useful under crowded band conditions.

The tuning rate for the tuning knob can be set via a button plus the ever-useful multi knob. I find that setting it at 100 Hz is the most useful for all-around work. For CW I might want to set it down to 10 Hz to be able to get the pitch just where I want it. There’s a nice spotting feature, too–just press another button and a tone comes on to indicate where the transmitted signal will be. The volume of the spot tone is variable (the menu plus the multi knob again) and the CW offset is also variable.

Hook the Jupiter to your computer via an RS-232 cable and, presto!–it’s a Pegasus! It’s really that simple. I like to use computer control when shortwave listening, as I can enter all sorts of information into the memory list and a station is just a click away. And, I can enter frequencies directly from the keyboard. I also find it very convenient to operate PSK-31 in Pegasus mode, since the radio is across the room from the computer and hard to reach. In Pegasus mode, I can do everything except actually turn the radio on from the computer screen. I found that the Pegasus software requires a COM port and the Digipan software requires another COM port (for the transmit/receive switching signal), so I had to purchase an additional COM card for my computer to get the extra port. And, it’s hard to purchase a long RS-232 cable these days. They’re sold now as mouse extenders–I had to string four together to get to my radio. (Yes, I know I could have built my own!) Note that the Pegasus feature is entirely separate from the built-in control capabilities–you can’t set a memory from Pegasus mode and have it be there in Jupiter mode, for example. [As of 2011: the Pegasus software does not work with Windows 7. However, you can use the excellent Ham Radio Deluxe software to control the Jupiter directly—without going to Pegasus mode. It offers better control than the old Pegasus software, plus I can make adjustments either at the radio or on the computer and they track each other!]

Judging from Ten Tec’s ads, they feel the Kenwood TS-570 is one of their direct competitors. It certainly was a competitor for my dollars! So how do they compare? Well, the TS-570 has somewhat older DSP technology–the Jupiter seems to outshine the ‘570 in that department. The ‘570 sports an internal antenna tuner the Jupiter lacks. The ‘570 has direct frequency entry the Jupiter lacks, but I use that for SWLing and do that from the computer (I’m listening to the BBC on 5975KHz as I write this). And, since the Jupiter is a software-defined radio, it can be upgraded at any time.

Let’s talk a bit about the upgrades. I’ve done two of them since I got the radio. Out of the box, the radio had firmware version 1.4 installed. Version 1.7 was available on the web. After making sure the radio worked, I downloaded and installed 1.7 through the RS-232 cable. Voila! The Jupiter now had a speech processor for transmit audio and an adjustable noise blanker. Just this evening I downloaded version 1.8. Voila again! The Jupiter now has AM transmit capability.

Since the radio was defined with digital modes in mind, there’s a separate connector on the back to connect to the computer’s sound card. I used the same interface box I’d built to connect the Yaesu to the computer sound card, though I did have to tweak with the levels a bit. The Jupiter even comes with a special cable to make the interfacing easy. The selection of which transmit audio to use (microphone or computer) is made via a menu entry (or via the Pegasus software).

Enough about features! How does the Jupiter perform on the air? In a word, phenomenally! I have a small antenna–a Butternut HF-9V ground-mounted vertical antenna up against a fence in between houses and trees–hardly optimal. I’ve never found this situation satisfactory for HF SSB, particularly on 20 meters. In fact, I’d pretty much given up on HF SSB with the Yaesu. Imagine my pleasure with all the HF SSB QSOs I’m suddenly getting. When the speech processor firmware upgrade was installed, I did some tests on the air with a ham in the Southeast to check out various settings. He reported it really punched up my audio without distorting it. I found a setting he liked the best and I’ve left it there ever since (for PSK-31 operation I leave it off). In fact, a universal feature of all the SSB QSOs I have is the comments about the excellent audio. During my very first QSO with the rig, I was informed I had “excellent audio quality.” The next QSO said my audio was “perfect.” One ham told me my audio was “clear as can be.” Another told me I had “nice and mellow audio.” And one ham responded to my telling him that the rig was a Ten Tec by saying that explained why my audio was so good.

Do I get out with my vertical and 100 watts? Well, since mid-February, I’ve worked all over the US and Canada as well as Japan, Australia, Russia, France, Germany, South Africa and Cuba. Not bad for casual DX!

So what don’t I like? Well, the manual looks a lot like an old military tech order. That’s understandable, since Ten Tec sells lots of general-purpose radio equipment to the government. But more pictures and diagrams would be helpful, as would an index. A separate manual, available on-line in PDF format, describes using the Jupiter in Pegasus mode–it’s odd this is not fully described in the manual that comes with the rig. And–and this is a major problem–manual updates are not issued when the firmware is upgraded. So I’m on my own to figure out the speech processor and the noise blanker. Ten Tec really needs to place something at the bottom of each page that describes which version of firmware the page is for, and change pages need to be issued as appropriate. Given Ten Tec’s reputation for excellent customer support, perhaps this is around the corner. On the plus side, the manual has complete schematics and parts layout diagrams as well as a complete bill of materials. I’ve set up a three-ring binder with the manual, the Pegasus emulation mode instructions, and the firmware upgrade notices to keep everything together.

Well, how did the test come out? After all, I obtained the rig on loan to see how well it would work with the solar power supply. The answer? It works very well indeed! So well, in fact, I bought the rig rather than send it back. Do you think Scott Robbins thought the rig might sell itself? I would imagine so!

Ten Tec sells only directly via mail order. That means you can’t go to your local ham radio store and test drive the rig. You’ll have to go out of your way to encounter a Ten Tec. Aficionados will tell you that Ten Tec rigs have phenomenal and very quiet receivers. I like mine! You can check out their web site at www.tentec.com. Price: $1189 [as of 2011 the price is $1595], which puts it right in the low-to-mid range for HF transceivers. I also purchased the 701 hand microphone for $28 [as of 2011 the price is $39.95 for the model 703]. The rig is offered with a 30-day money-back guarantee, less shipping.

Dave Casler, KEØOG, has been a ham for over 25 years. He enjoys HF PSK-31, CW and SSB and dabbles in every new mode available, especially if sound card software is available. He powers his ham station using solar (photovoltaic) power. You can see his article on solar power for ham radio in the April, 1996, QST. Dave is also the author of The Fox Hunt Adventure, a ham-radio adventure novel, available through MFJ or the Barnes and Noble website. Dave is a volunteer examiner, has been a BARC Junior elmer for several years, and wrote about BARC Junior for QST in the September, 1997, issue. Dave is a past treasurer of BARC and has coordinated several no-code tech classes for BARC.