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Re: Tariffs?
Radio-related aspect... Heard island is on the tariff list, I was reading this BBC article? and thought woaaahh, no humans have visited in over a decade? But I well remember the Heard island DXpedition, specifically because a QRP Labs Ultimate3S was on the ship and tracked the position accurately to 6-char Maidenhead grid subsquare resolution every 10 minutes reliably en route. Didn't seem that long ago! But I looked it up and indeed, it was 2016. How time flies! Then read further down the article and indeed it does say the last humans to visit the island were some amateur radio enthusiasts in 2016! 73 Hans G0UPL On Fri, Apr 4, 2025, 14:14 Greg McCain via <gamccain50=[email protected]> wrote: Well ... |
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On Fri, Apr 4, 2025 at 11:11 AM, Matti OH6BEX wrote:
0.8 A is to much. To start the controller you need Vdd at around 3 V. This voltage could be produced by IC101 but I guess there is a fault in the chain before. Pleas read QMX QMX_plus Startup to find this chain. A broken D109 is affecting Vdd. These values are not so bad and affected by the broken diodes. I guess you destroyed the PA and because of high current Q507 was following the PA in dead. Please don't transmit with a broken Q507 and read QMX QMX_plus PA problems, broken BS170 . Go to Terminal - Diagnostics (the controller will set a signal to switch off the PA voltage) and check voltage at D, G and S of Q507. If all values are nearly the same and high the Q507 should be broken. For more debugging check the Wiki page above. ?
73 Ludwig
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Re: Tariffs?
Well ...
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The newly signed hit list showed 10% for Turkey. But so far the reality has been changing almost daily. Bumpy road ahead is about all I'm sure of to be honest. I did see that there are entities on the list where the non existent populations are subject to tariffs. So ....? At this point, Who knows if the order and list are even accurate?? Or if the in place exceptions for small quantities/values still apply. Or if it all just grinds to a halt. Interesting times. Be careful what you wish for.? Try to have some radio fun today.? Support Hans where you can.? GREG
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Re: Tariffs?
Turkey isn't part of the EU And it isn't clear if or when or how much, tariffs will apply to small personal imports. There was an attempt in February to abolish the $800 deminimis for small personal imports but this was abandoned for reasons of impracticality. It remains to be seen whether this will be implemented and how. No US government website makes anything any clearer.? So in the end, wait and see is the only option.? 73 Hans G0UPL On Fri, Apr 4, 2025, 13:56 John Pokluda via <john.pokluda=[email protected]> wrote:
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Re: QMX won’t power up
Thanks Stan.
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That power supply was labeled as 12 VDC output (just a wall wart). I was a bit surprised to measure 13.4. The reminder and caution on using it is appreciated. It isn’t the one that was being used for operation, that one was flaking out so I had to swap a different one in. May be time for a real power supply.?
I’ll get inside and do the additional diagnostics. |
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Hello Stan, Ludwig and Kevin,
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I did'nt give up!?I ordered a mid-band QMX kit and it works good (but produces little bit too much power (6+ W) on 60 and 15 meters).
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The QMX+ rev 3 does not start. With power button pressed, it takes 0.8 A current which slowly decreases to 0.5A.
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Vcc and Vdd are around 0.1 V.
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Testing diodes with a DMM: D108 shows 0.17V and 0.2V, D109 shows 0.11V and 0.12V.
meaning that both diodes are damaged. But as the diodes are in-circuit, these values are probably meaningless.
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Resistances:
Vdd - GND 184 ohm
Vcc - GND 2.4 kohm
Vdd - Vcc 9 kohm.
These were measured with the DMM black probe at GND or Vcc.?
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But when I swap the probes, the readings are
Vdd - GND 1.2 kohm
Vcc - GND 313 ohm
Vdd - Vcc 1 kohm.
Why?
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I also received some spare SMPS'es and installed those to the older QMX+ rev 1 which I broke by accidentally inserting faulty SPSM'es from another faulty QMX.
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Receiver works ok.
Diagnostics page is all OK except TX Voltage which is RED showing 10.4 volts (DC input is 12.2V)
Pressing "T" changes TX voltage to GREEN 9.8 volts, power 0.0W and random SWR values.
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Apparently something in the TX chain is destroyed.
I have no oscilloscope. Is there something that I could check with an ordinary DMM?
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73 Matti OH6BEX |
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Re: Another QMX+ became SSB capable
Hi Jack,
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Did you go through the calibration cycle or just run with default calibration settings?
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It's just that I can get my QMX+ to do a complete successful calibration run and resulting in distorted audio.
Running the rig with default calibration settings (returned it to factory default settings), I don't get audio distortion, but mic volume is low. Increasing the mic gain then generates undesirable background noise. But that's a desperate challenge is need to resolve...
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Cheers,
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Mel. M0KMD |
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Re: RTC battery mistake
On Thu, Apr 3, 2025 at 11:50 PM, Paul G8MAD wrote:
The problem for me is that no matter what the ‘Real time clock’ is set to at power down the clock is always 00:00 at power up.What is the voltage on the VBAT line?? This is available on JP218, the three pin connector under the GPS module, the pin labelled 'Batt'.? It needs to be about 3V from the CR2032 battery, even when the power is off. ?
Chris, G5CTH |
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From my experience, it seems random. I got it to complete to about 2000 on one occasion after tinkering with the band settings for 20m. Without changing anything else, the next run only got it about 600 and was not able to get another complete run.
You can see my plots just a few posts below. /g/QRPLabs/message/142310
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@Hans, any theories as to why this is happening?
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Cheers.
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Mel. M0KMD.
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The LPF graphs give the impression that the LPFs aren't working, that there is a short bypassing all the LPFs regardless of the band selected.
One check would be to look for the 3rd harmonic being transmitted.? Do you have a receiver with a waterfall display? A SDR perhaps?? Try a test transmission into a dummy load and see if you can receive it at the fundamental frequency and 3 times that, for example 7.074 MHz and 21.222 MHz.? The dummy load will probably radiate enough that you can receive the signal locally.? If you get a significant signl on the 3rd harmonic then the LPFs aren't working. ?
Difficult to see why, other than some major miswiring.
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Chris, G5CTH |
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QMX+ low(ish) power output
Hi all, first off, thanks to Jeff Moore who helped my QMX midband, and noticed my silly mistakes.? Second off, I've just finished a QMX plus and am fairly happy with it except for the fact im getting 2-3 watts, leaning closer to 2 on all bands except 160m. I've reflowed all LPFs, PA, and tri toroids. Any ideas on where to look next? I dont think i have any failed finals or shorts.? |
Charles Schuler
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