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Issue #8: QRO with the Legal Limit Mercury LUX

Discussion in 'Trials and Errors - Ham Life with an Amateur' started by W7DGJ, Jan 18, 2023.

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  1. AC9YY

    AC9YY Platinum Subscriber Platinum Subscriber QRZ Page

    Does anyone know or has tested the 1dB compression point for the LUX. On the Mercury IIIs I found it to be right around 1 KW on 40 meters (15 watts in), so I typically run at that level or lower to reduce distortion.

    [​IMG]
     
    K9UR likes this.
  2. K0UO

    K0UO Platinum Subscriber Platinum Subscriber QRZ Page

    Rob Sherwood has been speaking at many events about this in the past few years.
    Pre distortion technology with SDR equipment is here to stay, and should be the BEST Practice of every ham.
     
    K9UR and W7DGJ like this.
  3. W7DGJ

    W7DGJ Platinum Subscriber Platinum Subscriber QRZ Page

    Steve (and Joe) -- I deleted the whole "RFKit" discussion from this thread, where it doesn't belong. If you'd like to post those issues on the general QRZ forums, they're wide open for you to do so. I am moving to a format here that is "only topics covered in the article" for discussion purposes. Thanks for your understanding. RFKit, Pure Signal and so on . . . they can go into another forum, Thanks.
     
  4. K2CD

    K2CD Premium Subscriber QRZ Page

    EDIT
    Never mind. Got it to work by tapping while I was transmitting.

    I can't get the analog meter to display. I've tried double tapping the Forward Power bar. Any other suggestions?
     
    Last edited: Feb 22, 2023
  5. W7DGJ

    W7DGJ Platinum Subscriber Platinum Subscriber QRZ Page

    No problem, there's a little spot on the peak power bar about a third of the way in . . . just touch that spot, and you'll see this Easter Egg
     
  6. AD4C

    AD4C XML Subscriber QRZ Page

    I do have the Mercury Lux and the Mercury AT and I am running up to 1300W to the tuner, it works fine with no arc so far, I am not running full legal power because the balun on my dipole antenna will not stand it and might burn but so far tuner has handle that power without a problem.

    AD4C
     
  7. W7DGJ

    W7DGJ Platinum Subscriber Platinum Subscriber QRZ Page

    I am doing the same thing, with the same amps. Dave
     
  8. K6JH

    K6JH XML Subscriber QRZ Page

    I'm sorry, Dave. But I'm not ready to let go of the Rf Kits vs Lux discussion. I'm a retired electrical engineer, and hate to see half truths spoken here.

    Yes - NXP doesn't make the BLF188XR anymore. They spun off the RF division to Ampleon in 2015. https://en.wikipedia.org/wiki/Ampleon

    Ampleon currently lists the BLF 188XR as "This product is not recommended for design-in." But it IS available for purchase. It is NOT discontinued. Manufacturers typically do this when there is a newer superior part available that would be a better choice for a new design, but they realize that their customers may incur considerable cost updating (potentially new matching circuits, FCC tests, etc), so they keep the old part available. As an example, my (former) employer uses many TI parts with that warning, has for many years, and has no plans to update - and TI is OK with that. Obsolescence is a fact of life in the modern electronics industry without exaggerating the actual problems.
    https://www.ampleon.com/products/extremely-rugged/50-v/BLF188XR.html
    Replacement ART1K6FH: https://www.ampleon.com/products/extremely-rugged/50-v/ART1K6FH.html

    Using a Raspberry Pi is not an advantage, considering they are unobtainable recently due to production issues, although I understand they are prioritizing their industrial customers. https://rpilocator.com/ Software is upgrade-able using a Pi or a microcontroller, and I've heard of Kenny sending out updated firmware when an amp wouldn't take a particular callsign entry. And once they get the firmware right it shouldn't need many upgrades anyway. (How many upgrades has my IC-7300 gone through? A much more complex product.) The Lux uses an ARM Cortex M7, but they don't say which manufacturer. Most semiconductor companies are so big they could wallpaper a company the size of KM3KM with chips, but of course shit happens these pandemic recovery days. I just don't see the Pi advantage. In fact the Pi itself has more parts to break, has cooling issues, etc. I think it's a huge overkill. While it might be nice having a web interface for remote control, I would be happy with an amp I treat as a black box. One can turn things on and off via a wifi AC switch, which gives me a way to master reset the station. Granted I'm using my one good laptop at my current station, rather than a dedicated desktop PC, so I'm not planning to go remote soon without a PC acquisition (IC-7300 remote requires a PC). YMMV.

    QSK? If you need it you need it. But PIN diodes, being semiconductor devices, are themselves an additional reliability risk compared to relays. Pick your poison. I'm not a CW guy, so...

    I don't appreciate hearing RFKits is blaming amp failures on "user errors". One of the major selling points of LDMOS is they are extremely rugged devices tested to 65:1 SWR or more. And a modern amp is supposed to be well protected against user error. Or is this just a manufacturer cop-out to blame users for design problems? It's kind of difficult to figure out the truth considering we don't have failure rate info, or knowledge of what parts failed, etc. Generally it seems to me that RFKits has had more failures, but my perception could very well be wrong. My impression is Kenny has bent over backwards to give priority customer service when users have a failure, while RFkits has to go through Island Amplifiers who handle other amp lines also. And I'm still wondering why DX Engineering ditched RFkits (I'm sorry - a cheap shot! But I still wonder!)

    Adding a $50 RF sampler coupler is a pretty easy way to implement "pure signal" in ones station, and avoids the potentially wrong signal level for ones particular SDR transceiver. Not particularly an advantage to be built-in. And considering the number of rigs that have actually implemented pre-distortion it's not an issue.

    Yes Kenny chose not to implement a built-in tuner in his amps. And the external Tuner he has available is rated for the IIIs, not the full power output of the Lux. If that's important to you factor that into your decision. I'm hoping a matching legal limit tuner is soon to be available, just for completeness. But there goes the Lux cost advantage. Of course not everyone needs a tuner, but my antennas typically need trimming, at least at the band edges.

    Both manufacturers have amps with dual LDMOS devices, which I think is an advantage compared to single device amps like the IIIs. More headroom, less dissipation per device (more reliable?). I haven't seen IMD measurements on the Lux or the RF2K, but I hope they're better than on the Mercury IIIs. I just haven't decided if it's worth the money for me to go legal limit.

    Yes, KM3KM delivery is an issue. But I'd rather get on a list than see them ramp up their production too fast, only to see the market slow once the backlog is satisfied. I want to see their business be there for the long haul. If delivery time is an issue for you, take it into consideration.

    Personally I need to improve my antennas before I go for amps, but I find the Mercury amps intriguing. I'm mostly doing FT8 these days anyway. RFkits seems nice but I'd rather deal with a small US company than a small German company. Both seem to be leading choices at the moment. Palstar not as much amplifier for the money. Acom having solid state amp issues, Flex is flex. Yaesu, Icom, Kenwood don't seem to have their hearts in amps anymore. MFJ? yeah right... Is Alpha really in business anymore?

    Choices are good!
     
  9. W7DGJ

    W7DGJ Platinum Subscriber Platinum Subscriber QRZ Page

    Thanks Jim for coming back to this thread. You write very nicely so it's hard to tell which side of the "debate" you are on, but anyone could appreciate the input. Once again, as a "user experience focused ham," I would point to the eHam reviews. There isn't anyone who has rated either Mercury amp at less than 5 stars. I'm sure there will be someday, but it's a grand statement of customer satisfaction that's for sure. John at Island Amplifiers is a great guy and just as qualified as Kenny to be fixing issues, but there are apparently more issues for RF-Kits and he's saddled with other work as well (he restores old gear, fixes all manner of radios, and has stuff stacked everywhere for service. Kenny gets one in, he does it that day and returns it!). Dave
     
  10. K6JH

    K6JH XML Subscriber QRZ Page

    I only know about Island Amplifiers from what John has put in his QRZ bio. Doing Island Amps as a retirement business out of his house. Several amp lines, and a repair business as well will keep him pretty darn busy. I wish him well. It's more than I can handle at a similar age.

    And Joe, K9UR, appears to be a well experienced ham also, who can bring his perspective to the mix. Certainly more experience than me. Especially from the CW and DXpedition end. I really didn't want to sound like I was coming down on him too far. He's just had great experiences with RFkits and wants to share. I hope his KM3KM order isn't cancelled - it would be nice to have a head-to-head comparison.

    I note Joe already has a pair of RF2K-S amps, paired with Palstar HF Auto and AT Auto tuners (in a SO2R setup?). Apparently the RFkits internal tuner isn't wide range enough for his antennas, the kind of thinking that went into the Mercury amp designs. My thoughts are it was probably a good idea to leave it out of the IIIs being a lower cost unit, but the Lux is a higher end fewer compromises amp and probably should have had the tuner built-in. And QSK. But it would drive costs up for everyone, even those that don't need the features. Lux Plus anyone? Or wait for the MercuryAT Plus?

    BTW, I was reading the QST review of the RFkits amp. Seems the imd was -33dB without pre-distortion. Unfortunately kind of typical for solid state amps, Mercury IIIs included. It improved to -45dB at only 1000W out. We all wish it was better at full output, but there's no way it's going to equal a good 8877 tube amp. And I'd rather be trying to buy obsolete BLD188's than obsolete 8877's these days - good tubes are becoming unobtainium!

    Kenny and Angel get to make their company choices and we all get to vote with our pocketbooks. From an equipment standpoint it's a good time to be a ham. Modern electronics is marvelous!
     
    W7DGJ likes this.
  11. W7DGJ

    W7DGJ Platinum Subscriber Platinum Subscriber QRZ Page

    I just reviewed an inexpensive ($200+) "folded dipole" cobweb antenna from Poland in the latest issue of T&E. Just ran some LUX numbers to see what kind of drive I needed to get 500-600W output.
    6 Meters - 24 W = 500+ W
    10 Meters - 12W = 500+ W
    12 Meters - 12W = 500+ W
    15 Meters - 9 W = 500+ W
    20 Meters - 8 W = 500+ W
    all of the above were under 1.6 SWR, and then I used the Mercury tuner on 40
    40M - 9 W = 500 W

    Nice amp, 500 W for this antenna is just pussy footing along.
     
  12. N8RT

    N8RT Ham Member QRZ Page

    Recently I saw a mercury 3s for sale on qth.com for $2900.00.
    I found out that the 3s on qth was a built from a kit and was about 2 yrs old. The kits back than, were priced at $2500,plus tax, plus shipping.
    I was tempted to buy!
    SO, I contacted km3km and asked what the difference is between the older 3s kit and a new one.
    This was the response their response:

    "Not many differences, one is that in the newer versions have FCC certification number and serial on the case and you can change your Call Sign via setup, the kits needed a file to change it.
    See you on the Air!!!
    Angel Ruiz N2PTB

    I have been on the wait list for a new 3s since June 2022.
    So I decided to just wait for my turn sometime in July 2023 for a New Mercury 3s , my cost would be very close to the used 3S.

    Rob N8RT
     
  13. W7DGJ

    W7DGJ Platinum Subscriber Platinum Subscriber QRZ Page

    Hi Rob -- There are a lot of bandits out there selling used IIIS and thinking they can make a profit. I sold mine to my buddy for $2300. I paid $2500 for the kit, had a blast building it, and operating it for a couple of years before my LUX came in. I consider that a bargain. I'm a very happy Mercury KM3KM customer, for sure.
     
  14. K7JQ

    K7JQ Ham Member QRZ Page

    Regarding the comments here that the LUX doesn't have a built-in tuner:

    The last thing I would want is a high power tuner in the same compact cabinet as a 1500W amplifier. Cooling the PA section and PS is tough (and loud) enough, without adding an additional heat source and circuitry of a tuner. As far as I'm concerned, you're looking for trouble down the road.

    A long time, quality company like Acom doesn't incorporate a tuner in any of their amps (and they're quiet). Flex Genius doesn't have one. At least Elecraft, with a tuner, has a separate PS with its own cooling. Plus, if you have a problem with the tuner, you have to send in the whole amp for repair. And if you have resonant-enough antennas that a SS amp can handle (SteppIR, etc.), you don't need a tuner...extra money spent for something not needed.

    Just my opinion;).
     
    W7DGJ likes this.
  15. W7DGJ

    W7DGJ Platinum Subscriber Platinum Subscriber QRZ Page

    Hey Bob, thanks for being here. I completely agree. There's no way I want a tuner built into my SS power amp, or any power amp for that matter. If you open the lid of a LUX, there's not much room in there. KM3KM has put a lot of good quality components into the box along with just enough cooling. Start to add more components, no matter WHAT they are, and you'll end up with trouble at some point. Dave, W7DGJn (PS Bob loved the desert antenna shots. Reminds me of my home.)
     

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