Re: Tone or birdie every 500 Hz in USB mode
If I disconnect the antenna, the birdies appear in the FT8 waterfall. When I connect the antenna, they disappear, presumably because the atmospheric noise swamps them. Maybe the AGC is a factor as well. I have a 1 meter loop and an active whip. The loop has
much lower output on 10 meters. On 10 meters I see birdies with the loop but not with the whip. I am talking about the 500hz spaced birdies on FT8.
I find it interesting also that Hans mentioned 500hz birdies coming from the ADC built into the microprocessor. They affected his microphone for SSB. I can't make a connection between that and the RX birdies but it keeps rolling around in the back of my mind.
Tony
AD0VC
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I think it can be corrected with filters or settings somehow. When I change to DIGI mode on the QMX, a lot of these noises disappear. In the image below, the bottom portion was DIGI, the top portion USB on the QMX+ (Pressed the Mode button just as green
line appeared to change to USB RX)
Whatever filtering or settings are different between USB and DIGI, the RX looks a LOT better in DIGI. Notice the lines at 750, 1250, 1750, 2250, 2750 are non-existent in DIGI. The lines at 500,1000,1500,2000,2500,3000 appear unchanged by this, but there
is definately something different between RX in DIGI and USB.
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In this picture, I cycle back through USB to LSB. The bottom half is USB, the top is LSB.
Notice that when I switch between USB and LSB the tone or noise at 1500 and 3k both become more pronounced (stronger signal indicated by line turning red instead of yellow) Also the lines at 500 and 250 get stronger (solid yellow instead of broken yellow).
Earlier today the LSB side was showing a pulsing tone at 750 almost like carrier from CW, but not in any CW pattern.. I did not get a screen shot of that while it was happening, but I now suspect it may have been an external signal. Note that all these signals
I am highlighting are with the radio connected to a dummy load with a 36" piece of RG-8x
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Re: QMX+ rev 3 freezes shortly after boot
On Tue, Apr 1, 2025 at 03:43 PM, @Ludwig_DH8WN wrote:
Michael, where did you connect the GND probe of your Meter to the QMX GND?
Could you measure VDD. You may use JP105 to contact VDD.
Could you measure the supply current from the beginning until the QMX stops?
Could you check temperature of IC101? But please take care it could be hot.
Thanks Ludwig! To answer the above questions:
- When connecting to GND I used either a GND port on one of the JP nodes, or the bar on the edge of the board
- Measuring through VDD showed the same results as when I measured R105 (which I had previously measured directly, one probe on either side of the resistor)
- during normal/healthy operation, it showed ~3.3V, and during the frozen state it showed ~4.5V
- I don't have an inline ammeter to measure supply current yet, but I have one arriving either today or tomorrow and can provide those readings at that point
- Temperature of IC101 was cool enough that I could touch it with my fingertip and and it felt about the same as room temperature, so about 17°C / 63°F
73, Michael
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Re: Tone or birdie every 500 Hz in USB mode
That confirms what I thought. It still seems like there is something firmware that could change how this behaves. Was just hoping there was a quick, easy solution. With these here decoding MFSK modes like MSK144 and VARA becomes difficult unless you have a strong signal, and MSK144 is a weak signal mode to begin with.?
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Re: QMX+ rev 3 freezes shortly after boot
Ok real help has arrived! CUL.
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Re: Low current BIAS SMPS
Q501???
Nice find.
Reminds me why carefully inspecting the whole board under magnification is so important.?
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I would like to purchase an assembled (working) 10 watt linear hf amplifier
I would like to purchase an assembled (working) 10 watt linear hf amplifier.
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Thanks,
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AC4OW, Sam
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I have ordered a low pass filer from eBay:
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Assembled 12v 100W 3.5Mhz-30Mhz HF power amplifier low pass filter LPF Kit
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Re: QMX+ rev 3 freezes shortly after boot
Also do you have the internal GPS? if so unplug it.
Also is it in a case? If so remove it.?
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Re: QMX+ rev 3 freezes shortly after boot
On Tue, Apr 1, 2025 at 07:54 PM, Michael Shiplet wrote:
However, the measured voltage across R105 went from ~3V (normal operation) to ~4V (frozen)
Michael, where did you connect the GND probe of your Meter to the QMX GND?
3 V ... 3.3 V would be ok. This signal comes direct from a controller I/O-pin and the controller runs from VDD 3.3 V. 4 V is wrong. Maybe VDD is going wrong after a few minutes. This would be dangerous for some IC especially the controller. Could you measure VDD. You may use JP105 to contact VDD. But TAKE CARE not to connect VDD to "+12V". This would destroy some important elements.
Could you measure the supply current from the beginning until the QMX stops?
Could you check temperature of IC101? But please take care it could be hot.
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I would avoid to transmit in the moment.
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73 Ludwig
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Re: QMX+ rev 3 freezes shortly after boot
Also replug the front panel and look at the display connection and while it's out check for a tiny bridge or a whisker that may be in there. That will answer a lot of questions before real assistance comes!
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Re: QMX+ rev 3 freezes shortly after boot
Alright, did the reset, correctly selected the QMX+ version from initial selection, and had about 2 minutes of solid listening time to a QSO on 20m. Thought maybe the reset was going to fix it until I went into the menu to change my keyer setting and it froze on me ?
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Re: QMX+ rev 3 freezes shortly after boot
Will try doing a reset next.
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Re: QMX+ rev 3 freezes shortly after boot
Just tried it - the board gave me enough uptime that I could send a few dahs. It looks like I'm barely putting out any power, but I did see the FWD meter on my ATU bump a little bit. I didn't wait long enough for the radio to freeze out though, so I was at least able to give it a gentle shutdown this time ?
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Re: QMX+ rev 3 freezes shortly after boot
Also is there time to do a reset before the pro analysts see this post? That will give you a headstart! I did notice a little quirky behavior on mine, right after I first powered it up.?
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Re: QMX+ rev 3 freezes shortly after boot
Do you have enough time to transmit into a dummy load on 20?? Does it kick out, immediately??
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Re: QMX+ rev 3 freezes shortly after boot
I have a rev.3 I didn't burn in yet. So let me see if it is working HiHi. You made me think ??
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Re: Tone or birdie every 500 Hz in USB mode
That pulsing signal like CW is what I get too, so I don't think it's external. It doesn't change with tuning, so it seems like something getting injected into the audio.
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73, Dan - W2DLC
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Re: QMX+ rev 3 freezes shortly after boot
Hi George,
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The 12V power source is a 6000mAh Talentcell rechargeable battery. To connect power to the radio, I'm using the included DC plug that I got as part of my kit, which I've joined to one of the barrel connector wires that came with the battery. So the battery's barrel connector connects to the battery, and the QMX+'s barrel connector connects to the QMX+.
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For the 9V, I just used an off-the-shelf 9V battery with a 9V battery-clip-to-2.1mm-x-5.5mm barrel plug.
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73,
Michael
N7WTM
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Re: QMX+ rev 3 freezes shortly after boot
Hi Michael,
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Please describe the power source in detail.?
Including DC plug.?
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73,
George?
K3GK
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Michael Shiplet
Braden Glett
Sam Hanie
Daniel Conklin