Re: Introducing QMX CARROT
When developing the QMX Carrot, I was initially concerned about whether the internal 1500mAh LiPo battery was sufficiently dimensioned. After all, the amplifier for the speaker still needs power.
Today I activated it for 1.5 hours and had 22, of which were 13 S2S with 61 points, and consumed only 386mAh at an average of 7.9V. Theoretically power for 4h more.
The QMX is a power-saving miracle with maximum of 3W out at 8V!
73 Chris
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Re: QMX+ Broken Toroid Core
Hopefully the HarborFreight superglue works!
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Re: FDIM 2025 - Bringing SSB to the QMX (Hans's presentation)
Hi all
I have just uploaded the 33-page PDF article which accompanied my FDIM seminar presentation. It provides some additional detail on the topics discussed in the talk. See?
On Sat, May 24, 2025 at 2:21?PM Hans Summers via <hans.summers= [email protected]> wrote: Hi Dave
Polar Modulation generated SSB is mathematically the same in the end as SSB generated by traditional filter methods or traditional SDR modulator methods. It sounds the same. The point isn't that polar modulation generated SSB sounds different, it doesn't. The advantages of polar modulation are that the efficiency is high, therefore smaller heatsinks are required and the lower power consumption (for a given RF power output) also presents potential operational advantages. Lower cost is also a result. For example Flex use the same heatsink in the new 500W Aurora, as in their current 100W transceivers. Abandoning the requirement for linear power amplifiers also means lower cost parts can be used and higher performance (lower intermodulation products) is easier to obtain.
Controlled Envelope SSB (CESSB) is a different topic. The amplitude envelope of speech is spikey. Unfortunately when speech is modulated to SSB, then it is mathematically inevitable that it gets even more spikey. The average power of the transmission is much less than the Peak Envelope Power (PEP). If you have a 100W transmitter the average power of SSB may only be around 15W. CESSB is a way to remove the additional spikeyness inflicted by the SSB modulation, without causing distortion or any other disadvantage. This increases the average power of the transmission by typically 4-5dB. Which gives it another S-point or so. A 100W CESSB transmitter typically has the average power equivalent to a ~250W SSB transmitter. CESSB again won't sound different other than it will be around 1 S-point louder, which could make all the difference in DX conditions etc.?
Parametric equalization is used to adjust the relative bass and treble content of the audio. That could be used to correct microphone response. More typically it is recommended to boost treble content and reduce bass content of speech, because the bass tones apparently contribute little to intelligibility. Of course this adjustment makes the speech sound less natural. So it's a tradeoff.?
Compression boosts the quieter parts of speech relative to the loud spikes. Which also increases the average-to-peak power ratio so gives more capability to break through in DX conditions etc. But causes distortion. So again a tradeoff.?
73 Hans G0UPL
On Sat, May 24, 2025, 12:29 David Wilcox K8WPE via <Djwilcox01= [email protected]> wrote: I have held this question in until now. I don¡¯t even know the correct way to ask Google, but with all these different ¡°improved¡± methods of generating SSB can the average ham (let alone the 80 year old like me) tell the difference when listening on the air?? Does it make a difference? Does the envelope hold open longer to increase power out or something like that. From what Hans has explained I get the feeling that some of the newer methods do increase the power out.
Thanks for any explanation or reference to a easily understood answer. On May 24, 2025, at 12:50?AM, Shirley Dulcey KE1L <mark@...> wrote:
? Did anyone out there notice that FlexRadio is now copying QRP Labs? Not really, but their latest product (the Aurora series, announced right around Hamvention and scheduled to ship in 4Q25) is using EER?(aka polar modulation) generation of SSB. They worked with K1KP, the developer of the Polar Explorer that was demonstrated in 2019, to integrate the technology into a transceiver.
Of course, Guido PE1NNZ and his uSDX beat both products to market. Hans explains it so well, I almost understand it.?
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Re: QMX+ Broken Toroid Core
Ed, I believe you can stick it together with super glue if it¡¯s a clean break. The toroids are made from a suspension of ferrite material in epoxy resin. So gluing it shouldn¡¯t be a problem nor should it affect performance.?
If you decide on a new part you can get one from?
Back in the early days of QRPLabs when I was part of the business that¡¯s where we bought our toroid cores from.?
73 Steve G0XAR
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Re: QMX+ Broken Toroid Core
Not really a master...it's just that I've broken enough to know they can be superglued together!
Jack, W8TEE
On Saturday, May 24, 2025 at 03:10:12 PM EDT, Ed Meyer, WG5F <groupsio@...> wrote:
Yes, Jack... Just two big halves... that's a great solution from the Toroid Master!
72,
-Ed, WG5F-
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Re: QMX+ Broken Toroid Core
Yes, Jack... Just two big halves... that's a great solution from the Toroid Master!
72,
-Ed, WG5F-
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QDX Low Receive but Xmit fine
GM QDX¡¯ers. I was gifted a QDX still in kit form so I spent a day building it this week. Except for one band, 80M, I got between 4.8 and 5.4W output which is optimal. The cure for that was to just put some more heat and re-solder leads on the inductors. I get reports of anywhere from -2 to -20.
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My issue seems to be with the received signal getting into WSJT-x. Although I¡¯ve made a dozen or so contacts on 20M and 30M, the db meter (I¡¯ll call the S meter) barely hits 15db maybe 20db on a real strong signal. Never higher. Most signals reports I give out are in the -17 to -10 range which would correlate with the db meter. I know from experience it should be a lot higher than that. I¡¯ve seen no signals decoded on 40M or 80M but I haven¡¯t listened at night which is going to be the most likely time to see those out in the NW.
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I¡¯m using a retired MacAir as the computer using OSX. All radio and audio settings are set to the QDX settings and to full audio by default. The Radio is set to a Kenwood TS-440. It gives the impression there is not enough signal/audio getting into WSJT-x but I¡¯ve got no way to adjust that. The antenna is a hexbeam for 20M and a 100ft high loop for 30/40/60/80
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The version of QDX is 1.4
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Any insight into this receiver issue would be greatly appreciated. I can live with the way it is now but I think with the receive signal stronger, it will show me a lot more stations. ?It may be MAC thing. I just don¡¯t know. Thanks.
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John / K7RLD
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Re: QMX+ Broken Toroid Core
KitsAndParts.com
On Saturday, May 24, 2025 at 02:36:16 PM EDT, Ed Meyer, WG5F <groupsio@...> wrote:
I'm in the midst of assembling my 2nd QMX+ and I just busted one of the Shiny Black T37-10 Toroid Cores...? DAGNABBIT!!!!
So, where's the best place to by only one or two Toroid cores in the US?
73,
-Ed, WG5F-
Tulsa, OK
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Re: QMX+ Broken Toroid Core
If there are just two large pieces, you can superglue them back together and it should work fine. If there are multiple chunks, things get a little dicey.
Jack, W8TEE
On Saturday, May 24, 2025 at 02:42:56 PM EDT, Ed Meyer, WG5F <groupsio@...> wrote:
Had all 24 turns of L512 wound and was trying to verify the turns count. ?Had it on a 3-D printed fixture and pressed down too firmly¡
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Re: Solder pot for toroid leads
I wanted a tool, but not something that would take up room on my small workbench. ?So I purchased a?
KNIPEX Tools - Coated-Wire Stripping Tweezers (1511120)
from Amazon, which is more expensive than a solder pot, but safer than a knife, which could potentially nick the wire (or fingers). ?A few swipes with the Knipex tool removes a good percentage of the ename. ?And it allows safely stripping only 2mm or so away from the toroid.
73, Ron, N6YWU
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Re: QMX+ Broken Toroid Core
Had all 24 turns of L512 wound and was trying to verify the turns count. ?Had it on a 3-D printed fixture and pressed down too firmly¡
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I'm in the midst of assembling my 2nd QMX+ and I just busted one of the Shiny Black T37-10 Toroid Cores...? DAGNABBIT!!!!
So, where's the best place to by only one or two Toroid cores in the US?
73,
-Ed, WG5F-
Tulsa, OK
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Re: QMX SWR measurement is not correct while using with PA
Correction:? You also need to know the phase difference between the voltage and current.? That's why you need two oscilloscope channels.
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>? If you find the magnitude of the voltage? and the current at the amp input port
>? using a two channel oscilloscope? and a series resistor to help measure the current,
<? then you have all the information you need to compute the complex impedance and the swr.?
?
On Sat, May 24, 2025 at 11:17 AM, Jerry Gaffke wrote:
If you find the magnitude of the voltage? and the current at the amp input port using a two channel oscilloscope and a series resistor to help measure the current, then you have all the information you need to compute the complex impedance and the swr.?
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Re: Solder pot for toroid leads
I wantched a youtube on the "$20 Amazon solder pot" and it looks like he had to fill the solder pot with almost a complete 1 lb(?) bar of solder, which seems to be about $30.
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So, I went looking a bit more and I found some google articles on building a small solder pot using a spare soldering iron (I know we all have those) and using a copper or brass cap with a copper bolt thru it. As a proof of concept, I built one. Cost for a new 25 watt Harbor Freight soldering iron and the brass cap and screw was about $9. The small cap obviously requires a much smaller amount of solder (than the 1 lb bar). I tried it on some extra wire and it seemed to work fine.
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I've wound toxoids before and used the scrape the wire and then blob on soldering iron tip before, but I never felt 100% that scrapping the wire was a bit of a pain.
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Time will tell if I actually use my small soldering pot or the scrap/blob method.
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Thanks for everyone's help.
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Roy de K2RMA
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Re: QMX SWR measurement is not correct while using with PA
Petrov,
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If you find the magnitude of the voltage? and the current at the amp input port using a two channel oscilloscope and a series resistor to help measure the current, then you have all the information you need to compute the complex impedance and the swr.? However the gates of the FET's present a non-linear load, the harmonics resulting from that will be seen at the input to the amp making this business of measuring amplitude and phase of the voltage and current problematic.? It could be argued that an SWR value for a non-linear load is undefined.? Many amps include a resistive attenuator to make the input look more like 50 ohms resistive, at the expense of reducing power available at the gates.? If interested in the many ways of measuring SWR and the math behind it, see my old thread at /g/BITX20/topic/94794749
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Jerry, KE7ER
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On Fri, May 23, 2025 at 11:24 PM, Petrov Sergey wrote:
Yes, looks like it is not correct to use Nano VNA for impedance measurement for PA. Thank you! Is it possible to measure imaginary and real part of impedance for PA in some other way?
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Re: QMX+ SSB audio distorted on one band only
I have a 20-10m QMX which I ran beta SSB firmware on. 20m wouldn't calibrate, but I tried Ellis Simon's band edge and band centre values and then the rig calibrated fine.
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I've just upgraded the firmware to 1.02 and I've hit the same problem of the 20m band not wanting to calibrate. I was a bit out of the loop but my rig was initially acting weird after the firmware update, I think I'd read somewhere about having to do a factory reset, but maybe I dreamt that, anyway, after a firmware reset, the rig now works fine. I figured after the factory reset, I'd have to do a recalibration.
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I'd like to try the different band edge / centre settings as I did before, but unfortunately the group has stripped the screen shot of the settings.
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Can anyone please share 20m band settings that worked for them?
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Thank you.
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Colin
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Dean,
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there is a fault in the SWR tune function (until now). If you start the SWR tune function your last VFO frequency is shown but a per band default frequency is used. Please rotate the frequency encoder to see the real frequency and tune to your wanted f.
As far as I know this problem is on Hans list.
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73 Ludwig
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Re: QMX won't start after firmware update to 1_02_000
Power down by removing the power plug. Then see if it will power up normally.?
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Stan, thanks for your answer.
Hans the creator hopefully sorts this firmware thing out one of these days (hint hint :))
Ari OH9VL
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Thank you Roger!!
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I was surprised to see the results into a dummy load so I went back to the original configuration and back to the same problem. So just curious to see my wattage I inserted a Barb-A-Watt meter in line. Now no problem with a fault.
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I guess it was a bit of rfi on the coax tripping the SWR protection. Simple solutions to simple problems.
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Thanks again, Dean
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Chris
Ed Meyer, WG5F
jjpurdum
Roy Ashkenaz