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On Mon, Jan 1, 2024 at 05:20 AM, Hans Summers wrote:
Which is normal because QMX uses DSP filtering.
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...is it possible to set the center frequency for either of the QxXes? Happy New Year to all of you! 73 de Razvan dl2arl
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For accurate power measurements you need a 50 ohm output impedance, a short cable to a good through line meter and a high quality 50 ohm load right on the meter output (or a terminator type meter)?
if you have the equipment replace the above with a T adapter in the Tx output, the 50 ohm load on one port and a 100MHz or better digital scopes¡¯ x10 probe in the third port so you can use the scopes RMS output figure for your calculation ( fir extra points add a filter to be sure you¡¯re only seeing the fundamental frequency power)
if available see if if a 3dB attenuator on the TX output half¡¯s the power etc ?(if not somethings not 50 ohm?
with non 50 ohm outputs, different loads, different meters and different cables/connectors/lengths I can get any number of different power ¡®readings¡¯ you like?
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FB, Hans !
72,
Bill, WB4HIO
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I've spent some time this afternoon identifying bugs with the 1.00.014 firmware. This is what I have found:
- calling CQ on 30m CW into a well matched antenna (SWR circa 1.2:1), towards the end of my CQ call the QMX stopped transmitting and all I heard was a continuous tone. The only way to clear this was by entering the menus and existing them without making any changes. However on exiting the menus a very loud click occured.
- semi QSK does not work - setting the option to either on or off has the same effect (of full break in). The manual does not say that this feature is not implemented.
- SWR protection enabled and it trips on an antenna matched at 1.2:1, the swr bar graph shows 1 and occasionally 2 bars when transmitting, with the swr threshold set to 3. If I change the threshold to 6 it still trips.
- what is incredibly frustrating is that each time I change bands the default frequency that is set is the FT8 frequency. This is not good for my ears. I thought that there was a default frequency per band but can't see that this is editable anywhere.
Last week I made a couple of cw qso's but gave up because of the keyer behaviour. When doing the tests above I was on 30m and no-one answered my CQ calls but in my CQ calls I didn't really encounter any odd behaviour (what I did encounter I attribute to my keying).
In my opinion changing bands would have been better implemented by a single press of the encoder. It is all too easy to accidentally change to digi mode by a single click and get deafened. Hindsight is wonderful!
Attached are a couple of screenshots of my keyer and protection settings.
73 Simon
G0FCU.
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That sounds similar to what happened when I fried my output transistors.
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Hello all,
I have a Rev2 board that I wish to run on the high bands and can't identify, from the schematics, the processor pin that needs to be grounded.?
Any clues please?
73 Phil G8DDN
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Thank you to everybody. ?I figured the response might be ¡°That sounds about right¡±. ?I just wanted to double check. ?I have a QMX that my son finished building yesterday and I was comparing them side by side this morning. ?It was apparent there was a difference between the two, but I knew the filtering was all DSP on the QMX.
Tnx agn and have a happy new year.
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On Jan 1, 2024, at 7:20 AM, Hans Summers <hans.summers@...> wrote:
? Hi Danny, Peter, all
Attached is a comparison of the QCX vs QMX CW filtering. These are actual measured responses. Not simulation or calculation. It's quite clear how much steeper the QMX filter edges are. Which is normal because QMX uses DSP filtering.
73 Hans G0UPL
On Mon, Jan 1, 2024, 3:37?PM Danny Bower < m0sdb@...> wrote: On Mon, Jan 1, 2024 at 12:10 AM, Peter GM0EUL wrote:
Are you sure there's something wrong with it? In my experience the CW filter on a QCX is very soft compared to my K2 and KX3.
Agree. The first time I used a radio without really sharp filtering it was quite a shock just how much activity I could hear above and below the frequency I was tuned on.?
The QMX is pretty good. I was using my Kanga Rooster yesterday though and there was a cacophony of dits and dahs either side of me.?
These days I don't think anything of it but it is distracting at first, particularly to a newcomer to CW :)
Danny M0SDB?
<cw comparison thick.png>
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Re: QMX SWR meter gone mad (SOLVED)
Good to hear it's working!
Having a slightly higher SWR on 20m is normal, try moving the 10 turn windings as far as possible from the 1 turn ones, it should improve it a bit. In my case, I couldn't make it go lower than 1.12.
73,
YO3GFH
op. Adrian
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Hi Danny, Peter, all
Attached is a comparison of the QCX vs QMX CW filtering. These are actual measured responses. Not simulation or calculation. It's quite clear how much steeper the QMX filter edges are. Which is normal because QMX uses DSP filtering.
73 Hans G0UPL
On Mon, Jan 1, 2024, 3:37?PM Danny Bower < m0sdb@...> wrote: On Mon, Jan 1, 2024 at 12:10 AM, Peter GM0EUL wrote:
Are you sure there's something wrong with it? In my experience the CW filter on a QCX is very soft compared to my K2 and KX3.
Agree. The first time I used a radio without really sharp filtering it was quite a shock just how much activity I could hear above and below the frequency I was tuned on.?
The QMX is pretty good. I was using my Kanga Rooster yesterday though and there was a cacophony of dits and dahs either side of me.?
These days I don't think anything of it but it is distracting at first, particularly to a newcomer to CW :)
Danny M0SDB?
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On Mon, Jan 1, 2024 at 12:10 AM, Peter GM0EUL wrote:
Are you sure there's something wrong with it? In my experience the CW filter on a QCX is very soft compared to my K2 and KX3.
Agree. The first time I used a radio without really sharp filtering it was quite a shock just how much activity I could hear above and below the frequency I was tuned on.? The QMX is pretty good. I was using my Kanga Rooster yesterday though and there was a cacophony of dits and dahs either side of me.? These days I don't think anything of it but it is distracting at first, particularly to a newcomer to CW :) Danny M0SDB?
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- ..-
-.. .? -.-. .... .-. .. ...
-- .-? ..- ... .-
--
Chris / W2BPL
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Re: QMX order form problem (kit/assembled)
#qmx
On Fri, May 26, 2023 at 03:25 AM, Iosephus wrote:
How would this kit be compared in difficulty with the truSDX? (My last successful kit)
The QMX is much more complex than the truSDX. There are many more components and the boards are much tighter. There are more complex windings to do as well.? However, if you have done a nice neat job of the truSDX and assuming you take your time and *follow the instructions TO THE LETTER * you should be fine. Just be aware just how tight some of the components are squeezed in and name sure you have a good soldering iron and a magnifier of some sort to help you.? The QMX is a more capable radio once finished and requires far less fiddling around tuning all the coils etc as well so it has distinct advantages.? I have both and the QMX is the one that gets used the most :)?
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Re: QMX output power 40 m vs 20 m (JS8Call)
SOLVED
After I fixed SWR bridge transformer, output has changed (and increased) on all bands.
With a fully charged Li-Pol battery and dummy load:
80 meters: 6 W out
60 meters: 6.5 W out
40 meters: 5 W out (~5.2 est. on 20 W scale)
30 meters: 5 W out (~5.1 est. on 20 W scale)
20 meters: 4.5 W out
Obviously, I have to think about the Si diode trick for a fully charged battery. Optimum supply voltage seems to be 11 volts, only 5 MHz output is then 6 watts, the rest is 5 watts or less.
73, de Jindra OK4RM
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Re: QMX SWR meter gone mad
I don't see how there can be any confusion.? Each end of the 10 turn winding has a wire that comes out of each end of the toroid and there is a hole for the 10 turn winding next to it. The obvious thing is to solder that wire into that hole.? Are people really deciding to loop both ends of the 10 turn wire back over the toroid and into the hole at the other end?
The pictures and text on section 2.14 of the assembly manual show this clearly.? The binocular toroid with the 10 and 1 turn pairs coming out of the toroid, not coming over the top.
Chris G5CTH
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Re: QMX SWR meter gone mad (SOLVED)
P.S. now I realized that in Power/SWR display the TOP bar is power and the BOTTOM bar is SWR (BTW I think this is not explained in Operation manual). With my SWR transformer screwed the top bar was very small (1-3 pixels wide in the first rectangle) while the bottom was showing "full throttle" - it was the SWR! Now it is exactly opposite: top shows full output, bottom remains empty when transmitting into dummy load.
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On Mon, Jan 1, 2024 at 11:56 AM, ok4rm wrote:
Hello, Adrian, thanks for the link!
I checked the windings. They look the same as in NorCal power SWR meter as well as the photo in assembly manual.
So then the only other possibility was that one end of one of the 10-turn windings, the ground connection, had no contact. When I looked in the schematic diagram, this seems to be the only possibiity, because then all continuity testing goes through other windings and there is apparent break in any of the windings.?
I gave all solder points some more heat, for the 10-turn windings I added a micro droplet of solder and heated the hole until I noticed that the solder was sucked in - this means that the enamel insulation has burned and the "naked" copper surface accepted the solder.
And voil¨¢ - dummy load shows SWR almost 1 (it gets worse towards higher frequencies, but still shows something about 1.17 at 14 MHz).
Uff, I am so happy :-D
73 + HNY de Jindra
On Mon, Jan 1, 2024 at 11:10 AM, Adrian YO3GFH wrote:
Ahoj!
I found a bit clearer description of the SWR bridge winding process in the Norcal powermeter assembly manual, page 10:
You should also check if the 1 turn windings are as far as possible away from the 10 turn ones.
Hope it helps!
HNY!
YO3GFH
op. Adrian
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Re: QMX SWR meter gone mad (SOLVED)
Hello, Adrian, thanks for the link!
I checked the windings. They look the same as in NorCal power SWR meter as well as the photo in assembly manual.
So then the only other possibility was that one end of one of the 10-turn windings, the ground connection, had no contact. When I looked in the schematic diagram, this seems to be the only possibiity, because then all continuity testing goes through other windings and there is apparent break in any of the windings.?
I gave all solder points some more heat, for the 10-turn windings I added a micro droplet of solder and heated the hole until I noticed that the solder was sucked in - this means that the enamel insulation has burned and the "naked" copper surface accepted the solder.
And voil¨¢ - dummy load shows SWR almost 1 (it gets worse towards higher frequencies, but still shows something about 1.17 at 14 MHz).
Uff, I am so happy :-D
73 + HNY de Jindra
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On Mon, Jan 1, 2024 at 11:10 AM, Adrian YO3GFH wrote:
Ahoj!
I found a bit clearer description of the SWR bridge winding process in the Norcal powermeter assembly manual, page 10:
You should also check if the 1 turn windings are as far as possible away from the 10 turn ones.
Hope it helps!
HNY!
YO3GFH
op. Adrian
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Jim,
Thanks for your advice. I decide to leave it there for now. I might try the adding capacitor method when I feel it's necessary.
73 de Lun BD8BTE
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Re: QMX SWR meter gone mad
Ahoj!
I found a bit clearer description of the SWR bridge winding process in the Norcal powermeter assembly manual, page 10:
You should also check if the 1 turn windings are as far as possible away from the 10 turn ones.
Hope it helps!
HNY!
YO3GFH
op. Adrian
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Re: QMX SWR meter gone mad
I checked continuity and all four connections are OK.?
So when I look at the schematic the most likely error is 10-turn winding orientation (A-A and D-D). The assembly manual does not specify winding orientation and honestly, I was not sure which direction is right. That could probably explain "infinite SWR" when connected to the dummy load.
OTOH why it shows more or less reasonable SWR with real antenna is a mystery...
73 Jindra
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Bill, N4QA/QRP
DL2ARL
Bruce Akhurst
Chris / W2BPL