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QMX Plus in contest
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Hi all,
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someone stated elsewhere, that the QMX+ was a good rig for contest. Not really I think. I just used it in the CQWPX as well as my Flex 1500. Well the waterfall is a + for the flex ( I dont want tb buy? more hardware to have one for the QMX) and changing the filters directly on the Hercules console is way quicker. I have not updated to the SSB software yet. The 300 hz filter is vy wide on the high side. Strong signals can be heard widely. Nothing after 0 beat.? Also strong signals seem to saturate the rx and that was a problem especially on 40 m? CW clicks are not nice but that is known. 160 m when the band is used above 1.840 is not workable as all stn from below have a similar signal there again. And then I have still to figure out how to set up the AGC. The hang time on strong signals is too long and that makes life difficult. On the positive side I prefer the audio sound of the QMX+ to the flex.
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I dont't want to be too critical and I never had a newer state of the art rig to compare.? Years back I had a TS 830 and liked that.? S next up is the region 1 FD for the QMX+
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Martin
DK3UW |
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You do give good information about some possible firmware changes to the QMX.
However, you're comparing the QMX to a rig that costs 15 times as much.
One would hope the Flex 1500 might be a little bit better in some respects.
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Jerry, KE7ER
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On Mon, May 26, 2025 at 07:23 AM, Martin DK3UW wrote:
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Jerry,
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I used a QMX+ as well in the WPX contest, which yielded 560 Q's working search and pounce; 5W into a 2 x 16m doublet up 11m.
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I have fitted a small board with an electronic T/R switch inside the case, that feeds a RSP1A SDR, controlled by N1MM's Spectrum Window feature.
This is mandatory for working S&P with 5W as the spectrum window shows how strong a paticular station is coming in, enhancing the chance he will hear you.
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Martin, I do not have the CW filter issue, but I am using as speaker a CW GUN, tuned to 700 Hz, which provides extra filtering, which might cover this issue up.
I noted some issues on 40M as well and will look into that. If it is really due to overload, I will build an attenuator with an electronic by-pass switch, controlled by PTT.
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Why? Because the QSK of the QMX+ is awesome and helps to win in a small pileup competing with much stronger stations.
Turn around time is very short and I am? heard often before anyone else has started yet, resulting in? .--.? .-? ..--..?
The QSK is just as good as in my RGO-ONE, which also features electronic switching only.
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Regarding high end radios, I sold my FTDX3000, which has very good filtering and noise reduction, yet suffers from listening fatigue and due to using relays has less than optimum QSK.
I have now three (QRP) contest radio's: the RGO-ONE, QMX+ and Elecraft K2, though the latter's QSK leaves a bit to be desired. The audio from all three radio's is excellent.
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My fasted rate in S&P mode was 40 per hour.?
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73,
Roelof, pa0rdt
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you are in my log your Nr. 557? Roelof.
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I had no rate of 40 but some over 30 but the high bands were painful. I ended up with 700 QSO's. Mixed QMX and Flex 1500. QSK is perfect on the QMX+ and Latency on the Flex is terrible. good, that the sidetome comes from the Winkeyer.? Unfortunately there is no really good QRP Rig available. I would love something with more buttons avoiding all these menue functions.? KX3? ?
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My antenna is a 160 m loop with ladder line and Johnson Viking Matchbox So band change takes time.
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Martin
DK3UW |
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Hello Martin,
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Using a spectrum display like the N1MM's Spectrum Window / RSP1A, it is obvious that quite a few strong stations have key-clicks that extend the transmit bandwith up to 5 kHz or more.
No receiver filter will get rid of these key-clicks. However, I found that with the QMX+ I can still listen a few hundred Hz from such stations.? Of course you will notice the key-clicks, yet it is possible to listen through the racket and work someone.
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I don't think that a perfect QRP contest radio can be found on the market, at least not at reasonable cost.
I have never used a KX3, but a K2 works also very well indeed for CW.
It needed some work for my style of operation. I have added a USB port and a RF-out port.
It is the basic version and has no fan which is a big plus as I don't use headphones.
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The RGO-ONE is excellent as well, though it has its quirks as well. The CW filter's far off attenuation is best using CW-R, yet N1MM set it to normal CW mode any time you click on the waterfall or type in the frequency and / or change bands. I have solved this issue designing and building a dedicated 6 pole 300 Hz wide 9MHz filter to replace the 4-pole Jones filter.?
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Maybe I will build a dedicated CW contest radio for 160, 80, 40, 20, 15 and 10M. For 6 bands it is very doable to use separate high efficiency power amplifiers for each band, like used in the QCX.
The receiver part is not too difficult and I have already build a nice 6 pole 5MHz 300 Hz CW filter. The main problem for me is implementing CAT control. I gather someone has already figured this out, though.
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I can changed bands very quickly as I am using a LDG Z-100 auto-tuner. The shack is upstairs and the open feeders of my doublet antenna enter the house at ground level. This way I have the maximum length for use on 160M, where the feeders are strapped together.
Measuring the antenna current in the feeders, showed that the LDG Z-100 followed by a good 1:4 balun, provided the same or better results than a manual balanced tuner. There is 10m coax between the radio and the LDG Z-100, which is activated by a separate cable and push button. On 160m the LDG Z-100 is by-passed via remote relay switching which engage a home made L-network tuner.?
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Regarding the RIT / N1MM issue, all OEM radios provide the RIT value as a plus or minus offset from the transmit frequency. As I understand it, the QMX+ uses a different approach: it provides the actual frequency the RIT is tuned to, rather than the offset. Anyway, the QMX+ is an amazing piece of kit!
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73,
Roelof, pa0rdt |
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