Re: #qmx #SSB Firmware beta 1_01_003 release
#qmx
#ssb
I wouldn't worry to much. Hans wrote regarding the calibration "The results are markedly different by band, this is normal. " and "Some phase error measurements do have weird glitches."
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73 Ludwig
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Re: QMX(+) Build experience, Poor Audio Filter Sweep/RF Filter Sweep/Image Sweep/ADC IQ test and resolution with new PCM1804
Finally got a 14.074 mhz signal into the QMX+ at about 17 mv. My Rigol DS1102E scope may be insufficient for this task but I can display the 17 mv signal at the BNC? but nothing at pins 1 and 7 on either IC405 or 406. So my problem? is likely back towards the BNC...
--
73
Karl
KI4ZUQ
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Re: #qmx #SSB Firmware beta 1_01_003 release
#qmx
#ssb
Hi Guys!
I managed to install the 1_01_003 SSB Beta on the weekend and
just took a few screenshots to provide another data-point for a
High-Band QMX.
Calibration was ok, but 20m and 10m look a bit suspicious. I still
need to build / adapt an external microphone.
All snapshots of my initial build and the SSB calibration on my
Google drive:
If the link gets filtered out, i give you the 20m picture inline
here:
10m looks similar
17, 15, 12, 11m more normal, as there is a dip with a clear
minimum visible in the graph.
No idea if my results are good, bad, normal, abnormal. Just
providing another set of measurements for you and Hans.
73 de Tobias DL3MHT
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First success yesterday with SSB on my QMX+ on 40m. Worked GB70RS at around 64 miles. He said the audio sounded good but to be careful of chewing the mic!
73
Tony
G3OVH
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Re: QMX+ Initial Power Up Display Shows Only Boxes
Hi Don,
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I just finished my build of the QMX+. I have completed two other successful QMX builds.
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So, today I applied power as suggested and wound up with the square box display. I figured it was the interface between the display board and the main board. I got the iron hot and reflowed as many joints as I could. After eliminating 99% of the possible I went back to the inside top header. So looking straight on from the front, over the top edge, start counting from the left to the right and pin #5 is the one. After I got the solder to flow from the pin to the pad?? --->? new QMX+ is on the air.
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Hope that helps.
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73, Dean/ N2TNN
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Re: Leaving 50-watt amplifier in-line but off
Hi Jim,
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I do not believe the PIN diodes have enough bias (reverse and forward) to allow the external transmitter to work.? It should be easy to install a relay that bypasses the amp altogether.
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73
Evan
AC9TU
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Re: #qmx #SSB Firmware beta 1_01_003 release
#qmx
#ssb
Dear all.
on my QMX, Rev2, 80m-20m, the diagrams for the ‘phase error vs DAC’ do not correspond to Hans' example. I have performed a factory reset. I have adjusted the band configuration: start, end and centre. See screenshot. I have disabled ‘20/80 BPF TXswap’ in the menu.
I would be grateful if someone could post the band configuration for a QMX 80m-20m as an example in this forum.
Stephan, DD6DO
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Re: Can't get SWR sweeps to be 1:1 with dummy load
Back on the air :)
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I chose in the end to just replace ic 402 and 403, and everything seems to be working fine now.
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I'm still not sure what exactly killed the chips. The limiting diode and the receive switching fet seem to be functioning correctly, but it's certainly fixed for now.
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Thanks all!
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Greg,
N1TR?
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Re: Qmx Single versus double click volume.
I actually removed the knob completely and it did not solve the issue.
so I have confirmed that there is no travel issues due to the ?knob restricting its ?movement.
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I used two different wires - The one that Hans provided and this one: . I did that in order to maintain color coding for the P and S wires. The P wire is the Amazon wire. At the very least, I seem to have cleared enough enamel to establish continuity between the center tap and the P on the other side. I'm going to try some more when I get home. Here is what I have:
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?
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On Tue, Mar 25, 2025 at 09:10 AM, Stan Dye wrote:
On Tue, Mar 25, 2025 at 08:57 AM, Chuck Harris wrote:
Unless you are using some exotic insulated wire, a few
seconds of exposure to the flame of a butane lighter will
easily burn off the enamel.
My experience is different, Chuck.? A simple roll of wire (certainly not exotic) I bought on Amazon from a quality manufacturer happens to have a high-temperature enamel.? So yes, I can burn it off, but only with with a high-temperature butane torch, but not a simple butane lighter flame nor any soldering temperatures.
Other wire types do have enamel that is specially formulated to burn off with solder or at low temperatures - you can often see it in their specs.
The .6 wire that Hans originally provided is somewhere between the two - if I didn't scrape it at least some amount, to significantly fracture its surface, it wouldn't burn off for me with soldering nor a simple lighter flame.? And I don't like to use a high-temperature torch.
Stan KC7XE.
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K used a lighter and tried scraping as well. I'm going to try with some hot solder. Thanks!?
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On Tue, Mar 25, 2025 at 08:57 AM, Chuck Harris wrote:
Unless you are using some exotic insulated wire, a few
seconds of exposure to the flame of a butane lighter will
easily burn off the enamel. After you have done that,
there will be a little oxide and smutz on the wires, so a
gentle pull through a folded piece of sand paper will
clean that right off.
Way easier than scraping, or sanding the insulation off.
-Chuck Harris, WA3UQV
On Tue, 25 Mar 2025 08:31:25 -0700 "Stan Dye via groups.io"
<standye@...> wrote:
If you didn't scrape the enamel off the newly-twisted 'A' center tap
on the right side, those two wires won't contact each other, and you
won't have continuity between the two left 'A' points - even if you
scraped the enamel off the outside of the twist. If you have the
finer-gauge wire, you can burn the rest of the enamel off with solder
and a hot soldering iron, if you have the thicker .6 wire, you need
to un-twist the A center tap and scrape the wires first, then twist.
Stan
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You're referring to the leads on the right (primary center tap), correct? If so, I did that, which I believe is how I'm getting continuity from left to right. However, I'm going to apply some solder to the twist in order to make sure that I'm not getting a false positive by touching one lead or the other. Thanks!
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On Tue, Mar 25, 2025 at 08:04 AM, <john.runchey@...> wrote:
You won't have continuity between all the P points UNTIL you twist those 2 P leads together. This threw me as well for a bit.
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In Washington DC on a beautiful day! Now to find my paddle so I can send anything apart from messages!
De AC3K
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Re: Leaving 50-watt amplifier in-line but off
Hi Nate.
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Transmitting and receiving.? I'd like to put a switch on the PTT going to the amplifier so that if I want the amplifier in the circuit, all I do is flip the PTT switch so that the amplifier will see 5V when the QDX transmits.
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I don't mind keeping the amplifier on all the time as the current used is nil.
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Jim
K8DDV
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On Tue, Mar 25, 2025 at 08:57 AM, Chuck Harris wrote:
Unless you are using some exotic insulated wire, a few
seconds of exposure to the flame of a butane lighter will
easily burn off the enamel.
My experience is different, Chuck.? A simple roll of wire (certainly not exotic) I bought on Amazon from a quality manufacturer happens to have a high-temperature enamel.? So yes, I can burn it off, but only with with a high-temperature butane torch, but not a simple butane lighter flame nor any soldering temperatures.
Other wire types do have enamel that is specially formulated to burn off with solder or at low temperatures - you can often see it in their specs.
The .6 wire that Hans originally provided is somewhere between the two - if I didn't scrape it at least some amount, to significantly fracture its surface, it wouldn't burn off for me with soldering nor a simple lighter flame.? And I don't like to use a high-temperature torch.
Stan KC7XE.
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Unless you are using some exotic insulated wire, a few seconds of exposure to the flame of a butane lighter will easily burn off the enamel. After you have done that, there will be a little oxide and smutz on the wires, so a gentle pull through a folded piece of sand paper will clean that right off. Way easier than scraping, or sanding the insulation off. -Chuck Harris, WA3UQV On Tue, 25 Mar 2025 08:31:25 -0700 "Stan Dye via groups.io" <standye@...> wrote: If you didn't scrape the enamel off the newly-twisted 'A' center tap
on the right side, those two wires won't contact each other, and you
won't have continuity between the two left 'A' points - even if you
scraped the enamel off the outside of the twist. If you have the
finer-gauge wire, you can burn the rest of the enamel off with solder
and a hot soldering iron, if you have the thicker .6 wire, you need
to un-twist the A center tap and scrape the wires first, then twist.
Stan
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Re: #qmx #SSB Firmware beta 1_01_003 release
#qmx
#ssb
On Tue, Mar 25, 2025 at 06:57 AM, Joel W9JFK wrote:
trying hard not to do a second transistor transplant. Not sure the patient would survive
Joel, when replacing the transistors 'next time' if there is one: just cut off the body of the bad transistors, leaving most of their lead-length in place and soldered to the board.? Then lay the new transistor in place, on top of the still-soldered leads, and solder the new transitor to the old leads.? Much easier, in my opinion, that cleaning out those vias.
Stan.
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If you didn't scrape the enamel off the newly-twisted 'A' center tap on the right side, those two wires won't contact each other, and you won't have continuity between the two left 'A' points - even if you scraped the enamel off the outside of the twist.
If you have the finer-gauge wire, you can burn the rest of the enamel off with solder and a hot soldering iron, if you have the thicker .6 wire, you need to un-twist the A center tap and scrape the wires first, then twist.
Stan
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Re: Leaving 50-watt amplifier in-line but off
Jim, are you talking transmitting through it, or just receiving?
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Nate
N8BTR
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Karl
DD6DO
Howard Lamhut