Ten-Tec 538 Jupiter: Conversations with Paul, GM4ULS

Paul, GM4ULS, and I exchanged several emails in August, 2013, about the Ten-Tec Jupiter, which Ten-Tec lists as their Model 538 HF transceiver. This great rig has been in their lineup for over a decade and was discontinued only recently. You can see what I think of mine here. The Jupiter is an early example of “software-defined radio,” meaning that critical processing steps are done in the rig’s firmware rather than with hardware dedicated to specific tasks such as demodulation. Over the past decade, Ten-Tec has come out with several firmware upgrades for the Jupiter, adding features such as AM, transmit roll-off frequency control, 60-meter operation, and (with a hardware modification), a CW receive capability plus the ability to plug in a PS-2-type keyboard for CW transmit capability. In our conversation we spoke of many features of the radio which may be of use to owners.

As shown below, Paul’s words are in block italics. Mine are in this color green.

Hi, this is GM4ULS here. I was drawn to your site because I have been offered a 2nd hand Ten Tec Jupiter 538 if I can get the money together by Saturday afternoon. It is being held in the second-hand section of a dealership that doesn’t usually carry Ten Tec equipment and therefore doesn’t know much about it. I know less still, and virtually nothing about SDR. I need to know the really dumb stuff like does it have to be hooked up to a computer ALL the time, or just when you’re setting it up? Can you help?

Hi Paul,

The TenTec 538 Jupiter is a stand-alone radio. It can connect to the computer via RS-232 for control if you want to. The TenTec website offers the Pegasus software so that you can control it completely from the computer, but note that the Pegasus software will NOT work on Windows 7. However, a far more satisfactory computer control solution is Ham Radio Deluxe.

If you do get the Jupiter, check the firmware—you may want to upgrade to the latest.

For digital, I use the SignaLink USB. The older Jupiters (mine is older) are exceptionally sensitive to input digital audio, so I have had to cut the level way down with some extra resisters. But it works fine on all digital modes I’ve tried. I generally use HRD/DM-780 for digital.

Hope that helps!
73, de KEØOG.

Hello Dave

A great help, thank you!

I do have HRD on an old lap-top, but I much prefer to operate a rig with my hands, and as my main operation is HF SSB plus some AM on 10m I’m not too concerned about its performance on digital modes – I used to operate RTTY, packet, and more recently PSK31, and may go back to digital one day, but not right now. (All of our computers currently in use here at home are Apple anyway)

How would I check the firmware? What is the physical process? Would I need to connect it to a computer for that? Please excuse the basic questions.

I visited the Ten Tec web site yesterday and did not find any link there for firmware; where should I be looking?

In the world of SDR, therefore, it seems as though the Jupiter is a ‘set-it-up-the-way-you-want-it-by-software-then-run-it’ radio. 🙂



PS. I just found out that the rig I am buying has the internal ATU fitted. Any tips? Can the internal ATU be switched out of line? It also has 5 MHz capability, and I would be using a random-length doublet, fed with ladder line, via an external ATU, for that experimental band.


On the older firmware, the version shows at power-up. For newer versions of firmware, press ALT and then STEP and the screen will briefly display the firmware.

Yes, the Jupiter is an early example of SDR, but it doesn’t allow the flexibility that you’d find in a modern (and expensive) SDR. Still, it’s pretty impressive. I particularly like the wide range of filters. And there are many, many options in the menu.

For the firmware downloads, plus other downloads such as a PDF copy of the manual, go to http://www.tentec.com/pages/Transceiver-Downloads.html.

73, Dave

Hi Dave

The wonderful thing about it is that it is – as near as makes very little difference – the kind of simple rig I would have invented. Many’s the time I’ve lain awake ‘designing’ a rig in my mind, and suddenly I find that it had been out there all the time. Albeit the technology has moved on since the Jupiter was introduced, users whose comments I have seen on line seem to regard it as a very good rig. The only major criticism I have seen was from someone who felt that the multi-purpose knob was a little inconvenient.

The one I have been offered, at less than half the original price, has a built-in ATU, a desk mic, and 5MHz (I’m hoping that this means the UK allocation, not the US allocation as per original firmware); so as long as it sold to me fully-working I think I’m getting a good rig for a good price. I have downloaded the manual and am having a read through. I’m going to see the rig this coming afternoon.



PS. Currently my main HF station is a Yaesu FT-847. I also run an FT-101ZD on 40m. I will be keeping both, as the 847 gives me 4m, 6m, 2m, and 70cm, and the 101 used to belong to my Dad and is a superb rig.


The antenna tuners in TenTec rigs tune up to 10:1 SWR, a much wider range than most. I’ve never tried one—my rig doesn’t have one.

All Jupiters with current firmware have the US 5-MHz band—not just specific frequencies. I don’t know if that is the same band as in the UK.

Note that since the rig is out of production, we likely will not see any further firmware updates.

73, Dave

Hi Dave

It would be a pity if they didn’t do some updates – a bit like stopping making parts for last year’s car!

Anyhow, I have the rig here. it tunes from 5.313MHz upwards, so it lacks the bottom portion of the UK allocations, but it still has a useful and useable part of 60m.

Overall it seems to be a pretty good rig. The only problem I seem to be having is making any great impression on a power meter. Even with PWR at 100%, MIC at 100% and speech processor at 100% (via the menu), I still had to ‘swallow the mic to hear myself on MON over the headphones and to get any respectable PEP. The mic is a Ten-Tec desk mic model 705. Any suggestions? [By the way, I have used two separate external power meters to check the output; both report much lower into my antennas and dummy load than the 847 and 101. I’m wondering what I might be doing wrong.]

I have had three QSOs on 60m and am currently monitoring the UK beacons GB3RAL, GB3WES, AND GB3ORK, which are all well above my noise floor. The QSOs reported that the audio on the Jupiter sounded good. However, I have also tried some HF, giving away points in a contest on 20m, 15m, and 10m, and stations kept asking me to repeat my report; that could have been a totally unrelated factor, but it made me worry a little.

Still, the rig is very easy to learn one’s way around.




One of the items in the menu (MNU button) is “MIC IN BOOST” (way down at the bottom). It defaults to zero. Try cranking that up. For my TenTec 777 DX Pro headset, I need to crank MIC IN BOOST all the way up to 18 dB! Crank up MIC IN BOOST (the menu item, not the button) so that you’re running MIC (the button, not the menu) at about 50% with full power out.

I really don’t hear myself with M-LEVEL at 100% either.

I get good reports on audio quality too.

(Press MNU, use main tuning knob to select an item, and then the MULTI knob to select the options. Press MNU again when you’re done.)


Hi. Thanks, that makes a lot of difference. For a relatively modern, menu-driven rig, the Jupiter is so easy to find one’s way around.

I have also discovered that I can get the rig to transmit over the whole of 60m, so job done.

Thanks a lot for everything. You’ve been very helpful.



Do you mind if I put this exchange up on my website? The items discussed could be helpful to lots of other people.

Enjoy that Jupiter!

73, Dave

Hi Dave.

Just amending what I said previously, I have the whole of the UK 60m allocation except for the two CW segments at the lower end, which are used for CW. As I seldom use the key, this is not a problem. Talking of the key, I plugged one in today to see what the top whack of power was on CW on 5MHz and 7MHz. It seems to be 117W; bearing in mind that it was not measured on the most brilliant meter, that’s still pretty good. And now that you showed me where the ‘mic in boost’ is, I no longer need to swallow the microphone.

Do you know what the companion linear amplifier is/was for the 538, by the way?

Yes, please feel free to quote this conversation. I was about to compose a short report on my first impressions of the rig on my own web site. I realise that there must have been a large number of ‘rig reviews’ when the rig was first rolled out, and I’m not very technical, but it’s something to write about, and of course the rig comes up on the second-hand market fairly often. I’ll give you a summary of my first impressions now and you can include them too. In fact you might be able to put me straight on a number of issues.

The reviews and comments I have read on on-line forums have been universally complimentary about the Jupiter. The one niggle someone raised was to do with the multi knob, and having to shuttle between RF gain and AF gain; he suggested two concentric knobs (each doing half the work of a single multi? Who knows!). I haven’t had the same problem, because I tend to leave the RF gain on full, and press the ATT button if I want to back it off a little. What I do notice, however, is that there appears to be no way of adjusting AF gain, or putting out a TUNE signal, or effecting any other change when one is in memory mode, because touching any front panel control takes the rig out of memory. The only exception appears to be the main tuning control. The trick – unless you know of a better way – is to set AF gain etc before entering memory mode. Same goes for STEP – there’s nothing more tedious than tuning through an AM broadcast band in 100Hz steps!.

A very minor thing: the Bandwidth and PBT controls could do with an indication of ‘dead set’.

I’m currently using an external speaker, actually an old Yaesu SP-901. It’s marginally better than the built-in speaker.

I use the internal ATU when transmitting on 14Mhz to 29MHz. My antenna is a MA5B mini beam, which is a pretty good match, but is not perfect across the whole of each band. For 10MHz down, I switch off the internal ATU and use an external one (antenna is a doublet).

Again thanks for all your help.


[And more, apparently showing that updating the firmware won’t work without the hardware upgrade. (It appears the hardware update is no longer available on Ten-Tec’s website.)]

Hi Dave

Here’s a peculiar thing. I just did a firmware update. 1.32 was the version already in the rig, and I downloaded v1.33. I went through the process as instructed on screen, yet the rig still says 1.32. Could this be because I haven’t reset the rig (power up pressing any function button)? I am reluctant to do this unless I know it will work; it would be unfortunate to lose all my memories if the firmware still won’t be updated.

Any comments gratefully received.


Hi again Dave

I have been trying the ‘hidden menu’ items. I found that they don’t work if you hold down the ALT button, but they DO work if you touch the ALT button so that ‘ALT’ is blacklighted on the screen, and then operate the appropriate button. It’s worth noting that the ‘band up’ command only works once, it doesn’t toggle the band button into going up rather than down.


Exactly. It’s not like holding down the shift key on a keyboard. Press ALT, release, and then press the desired key, just as you discovered.



I haven’t done this in awhile. A look in my notebook shows that the firmware update ends with a master reset. I don’t use memories, so I did a master reset to see what happens. Everything, and I do mean everything, is set back to factory original. That means the memories are zeroed out and all the settings you changed in MNU are set back to factory defaults also.

73, Dave

I take it it won’t matter how long you leave it after the update – the next master reset will do it?

I think the thing to do is make a note of all the menu settings. I already have a copy of my memory channels.


[And added:]

Hi again David

Just letting you know that I did a master reset and ended up with the old firmware still in place. I’m going to try something else and I’ll get back to you.



[And a bit more:]

Hi Dave

Just a note to say I have tried a second update, to no effect. I wonder what I might be doing wrong.

It’s no big deal using the 2008 firmware as opposed to the 2010 – the rig performs very well and does everything I want it to.

Thanks for your continued interest and patience.



I played around with mine a bit. I have the most recent firmware. But mine also has the hardware modification that allows for multiple personalities. There’s also firmware in my machine for a “CW” personality. It allows the use of a standard PS-2 keyboard for CW keying, plus has an intriguing but largely unsuccessful CW decoder that shows up on the screen where the spectrum analyzer normally displays.

It is possible if yours does not have this mod, you may be unable to load the most recent firmware. In terms of the difference it’s made to me, it’s of negligible consequence – sometimes the CW personality is okay to just play with, but mostly I use the standard “538” personality.

73, Dave

Hi Dave

That’s a distinct possibility. I notice that there are three distinct files (I haven’t got a pc running at the moment so I can’t tell you what they are, but they all have the firmware extension) included with the v1.33 package. I guess it’s possible that one has to try to upload those before uploading the one which is most clearly marked as version 1.33

I’m not hampered in any way by the currently-uploaded firmware, except for missing a small portion of 60m, and the fact that although the rig receives on AM it won’t transmit in that mode. The PTT mutes the receiver but doesn’t put out any RF. Again this doesn’t hamper me too much, apart from the fact that I like to operate 10m AM but it makes me wonder whether there’s something I don’t have ‘plugged in’.




You can find instructions for operating the Jupiter on AM at this link.

73, Dave

If you have any additional Jupiter tips, please add them in a comment below.

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8 Responses to Ten-Tec 538 Jupiter: Conversations with Paul, GM4ULS

  1. dcasler says:

    Tim, the monitor function just assures you that your voice is going out over the air–you are monitoring transmit SSB audio. It’s not terribly loud and can be turned completely down if you want to. I much prefer to have monitor ON. Sorry to hear about the tone glitch. I’ve never had that particular problem. Go through the manual line by line. Don’t forget to look at the supplements that came out with firmware upgrades. The only singular issue I had with mine is that the cat threw up all over the screen once, and before I could get it all wiped off, it has gotten down into the front panel controls. That resulted in my sending it back to TenTec for a thorough cleaning and repair!

  2. Tim Young says:


    After getting my ticket a few years ago, my Elmer helped me purchase a Ten Tec Omni D (because I am the LEAST “tech-y” ham anyone in the hobby knows, it was thought that a stout “final” would ward off accidentally frying my rig until I mastered better operating technique). Needless to say, I have become a hopeless knob turner!

    I love my Omni D, but got the itch for digital modes, and suddenly the old tube radio doesn’t appear to be stable enough (although some tell me otherwise, I just don’t have the technical savvy to pull that off). Then my antenna mast experienced a catastrophic collapse – and I wasn’t able to get another immediately back into the air…for the past 3 years I’ve let many things take priority over the hobby that I love…but no more!

    I read your blogpost above, along with some other research on a Jupiter 538 – and decided to purchase a Ten Tec Jupiter 538AT from eBay! It was being sold by a ham who said he was upgrading to a newer rig after several years of happy use. The seller had the paperwork for all repairs, through in a package of cables for numerous digital modes, and stated all the available firmware upgrades had been done. He even posted a video of the Jupiter being tuned up on 40 meters from a dipole (no transmit, just receive). So I don’t think it’s the Jupiter.

    I recently set up my “temporary” QTH in another state – utilizing a fan dipole for 80m, 40m, and 20m. I listened for several days – without the desire to call CQ – when I did finally have the urge (it’s been sometime since I was on the air), I couldn’t seem get the desk mic to transmit? Each time I pushed the PTT button, I got a long, loud tone (yes, I scanned through the manual, and am in the process of re-reading it)!?

    I read the rig has a “MONITOR” mode for listening – but despite reading the manual – I don’t see a way to take the system OUT of monitor (if it even is, in-fact, IN the MONITOR mode)…do you think this might have something to do with my issue?

    I ask because I know you used to have a Jupiter 538 – I was wondering if you might be able to offer some insight?

    By the way – I LOVE the sensitivity and it’s my first experience with a built-in antenna tuner – so I’m not disappointed, just wondering what sort of OPERATOR ERROR may be causing me to limit my fun to RX?!

    I know it’s somewhat off-topic – if you prefer to address by email – I have included it as well.

    I know you’re busy – if you can’t get to my answer I’ll understand – I do so enjoy your YouTube videos, maybe you’ll address it there some day!

    Love your stuff, keep it up!!

    Tim de KK4MEQ

  3. David Casler says:

    Look at your antenna system. The TenTec will “fold back” the power output in the event of an antenna fault. After that, try a complete system reset of the TenTec. If that doesn’t work, you may be looking at having it repaired.

  4. Hi. I had forgotten all about this ‘conversation’. I came across it because I was doing an internet search for loss of power on a Ten Tec Jupiter. Suddenly I’m only transmitting at somewhere between 3 to 6 watts, whether with SSB, CW, or the tune button. The power setting is at 100%. Any ideas? Low-tech preferred hi hi.

  5. Lee--WS4BS says:

    Does anyone know a good place to tap the 45 MHz IF for a pan adapter?

  6. charlie says:

    the serial cable was bad, replaced and it works fine

  7. charlie says:

    i have a jupiter, did a reset, reloaded the latest firmware through a serial cable it took the update, but i cannot get the radio to connect to the computer HRD program, anyone have any suggestions that might help, i am running win 7,

  8. Paul
    I have a problem with a jupiter that I have had on the bench for some time, it has no out put. I thought it was the PA but if I put audio on the J1 pin and push the PTT I can geta 100 watt out put. The circuit board was a 81889 and it was changed to a 81962 board. This is the problem that I have, U18 and U19 were MC1496D’s and in this circuit board that I have now after I sent it in for repair has U18 and U19 are NE612A’s and there was a change in the driver, it had a 2SC1971 in the circuit but was changed to a RD06HHF-1 fet, with other changes to the circuit board.. I would like to know if you know anyone that has this schematic? Having a problem with audio not getting passed Q32 to Q27.. Have any ideas?

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