Yes Paul, there is a DC short between the center pin and ground of the BNC……but NOT at RF.
Len KJ9E
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Re: Full Band Coverage QMX+
Trevor,
I am not sure what you mean by not being able to cycle through all the bands but that you can see all the bands.
I would try Roger’s suggestion of a factory reset and make sure you select QMX+ to enable 160-6. If the previous owner disabled bands that they were not interested in, the reset should change those back enabled status. Just be careful of transmitting on bands where your antenna is not resonant.
You should be able to receive and transmit on ALL the bands 160-6, presuming that you have appropriate antennas. Tweaking of the toroids might improve your power output on a particular frequency but even on the bands with “lower” output than I might like, I still have lots of worldwide contacts with a vertical antenna.
Len KJ9E
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Hi
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Stan
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I removed and resoldered L502, checked reheated T501 and T507 at 370c for 10 seconds, and then checked with a multimeter in Ohm’s mode; all made good connections.
I have uploaded some pictures to ?
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There is a short between the BNC's centre pin and the ground. Is this normal? There is still no Tx, and the SWR is random.
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Cheers
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Paul
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M0PNN
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Re: A question about L401 windings QMX v1 vs QMX v2
No problem Charles...glad it worked out!
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I know the L401 winding question has been beaten to death, but I haven't quite found the differences between version boards...
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Anyway, all the best for the new year.
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Scott VY1CO
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Re: QCX Mini 20m - help please ??
Thanks! I will open it up and inspect the BNC connector. I'll start there.?
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Re: QCX Mini 20m - help please ??
Lidiette,
It does sound like you are getting some RF back to the rig from somewhere. Maybe a wire is broken on your antenna, or the feed line has come loose, or the BNC connector has broken or come loose, but it's something like this that could have changed and is causing the problem.
--
73, Dan - W2DLC
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On Sat, Dec 28, 2024 at 05:46 PM, Sergei Ivanov wrote:
https://www.nonstopsystems.com/radio/frank_radio_antenna_SM0VPO.htm
?Thank you!
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Re: Diagnostics fail with no BS170s installed
#qmx
Hi Chris,
Well done, excellent news. It was definitely a strange fault and worth noting for future reference.
73, Dave
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QCX Mini 20m - help please ??
Hello everyone,
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I have been having an issue with my QCX Mini 20m where I am unable to access any of the menu or even change the tune rate. This happens after I start transmitting (calling CQ CQ). The antenna that I am using is resonant to 20m. I have even used an antenna tuner as well. ?I used this radio without having these issues for a while. I am not sure what I could have done that is causing this problem.
Any suggestions on how I can try to fix this issue??
Thanks everyone in advance,
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Lidiette
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Re: Diagnostics fail with no BS170s installed
#qmx
On Sat, Dec 7, 2024 at 02:18 PM, Chris wrote:
I've got 10 MS5351Ms on their way from China.? Not holding my breath.
?
?
Finally summoned up the nerve to replace the MS5351 IC.
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This is a tiny IC, 0.5mm pin spacing, I'll describe what I did:
before:
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I used a soldering iron with a chisel tip bit, about as wide as the IC pins.? Board fixed down, lots of light started with two pairs of +3.5 reading glasses (as well as my normal ones)
I attacked the IC one side at a time, flooded the 5 pins with solder and lifted the pins a little.
Then the same on the other side, and after a bit had the old IC off,
Cleaned the pads solder and flux, then solder wick to remove excess and IPA.
Then the tricky bit.? Held the IC in place and tried just to touch one corner to get a few pins located and fixed. once lined up flooded both sides with solder, not worrying too much about bridges.
Then removed excess solder with wick, several times.? Inspected and tested for the absence of bridges.
I didn't look at this photo before declaring it finished, pins 1 to 5 aren't perfectly aligned.
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Still testing shows that all three clocks are the correct frequency.? All the diagnostics work, and it reports about 1.2W out running on 7.5V.? The scope shows the correct frequencies out.
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So it was a faulty MS5351.? Really strange.
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Chris, G5CTH
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Re: QMX+ Receiver MDS measurements. (noise bandwidth of a FSK signal) (coherent CW)
Hello Eduardo,
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Using a linear phase filter, ringing is not an issue, even with a 10 Hz bandwidth.
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It can also be done in software, e.g. Linrad can be used for single side-band CW reception in a 6 Hz bandwidth, plus the ability to use as many notch-filters in the same bandwidth as you like.
This is insane, yet I have used it to achieve aural copy of very weak non directional beacons? at long-wave? sitting very close to adjacent carriers.
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73,
Roelof, pa0rdt
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?
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Taken completely from here: https://www.nonstopsystems.com/radio/frank_radio_antenna_SM0VPO.htm . 14 MHz option. Coaxial cable about 10 m through RF choke.
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Re: Full Band Coverage QMX+
Hi
You probably need to do a factory reset from.the menus, and select QMX160-6 when it restarts.
73
Roger
8P6RX
Get BlueMail for Android
Do I understand the manual, that using all bands is not practical as one has to tweak the band pass filters for specific bands? Example 80-20 only, not 160-6. ?I see I can select all bands, but my rig won’t cycle through all bands. ?I purchased this QMX+ used, and just started using it. ?Thanks for the input. ?
--
Trevor (N0YMA)
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Re: Full Band Coverage QMX+
Do you have it set as the QMX+ in settings?
On Sat, Dec 28, 2024, 11:14?AM UPNORTHOF48 : via <trevorogden66= [email protected]> wrote: Do I understand the manual, that using all bands is not practical as one has to tweak the band pass filters for specific bands? Example 80-20 only, not 160-6.? I see I can select all bands, but my rig won’t cycle through all bands.? I purchased this QMX+ used, and just started using it.? Thanks for the input. ?
--
Trevor (N0YMA)
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Do I understand the manual, that using all bands is not practical as one has to tweak the band pass filters for specific bands? Example 80-20 only, not 160-6. ?I see I can select all bands, but my rig won’t cycle through all bands. ?I purchased this QMX+ used, and just started using it. ?Thanks for the input. ?
--
Trevor (N0YMA)
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Looks great Sergei, congratulations! What are your dimensions for the wire frame, and how do you feed it?
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73, Peter HB9EBE
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Re: 12V battery not playing well with QMX
I use this without any problems:
works very well since a year in shack and portable
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may you give it a try?
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vy 73 de Udo DF4BJ?
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Hi Evan,
The IFR510s have been on my prime suspect list. I replaced them a while back from digikey and all seemed well. I put the thing on the shelf and just picked it up recently to play with and notices this problem.?
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It doesnt seem to make too much heat to get started. The heat sink barely seems warm. In fact, the insides get warmer overall than the heatsink.?
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Also watching the power drop with a scope, it can be seen in the circuit all the way from the input bnc through the entire amp. Would that make sense?
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Qcx+ by it self is not doing this so I think the radio is okay.
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Could a cap be thermally affected this way? Could a winding short do like that?
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I dont mind shotgunning some but would like to avoid board damage removing parts as much as possible. So hoping to narrow this down somewhat.?
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What would one replace these thermal insulator pads with?? Ones I have aren't beat up too badly except a little chewing around the screw holes. Thermal paste? Yuk ...hate to go there but I could.
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regards,
Bryan, N0LUF
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So, I have a new favorite toy - QMX+. From order to receiving the kit - 7 days. Assembly took two days. Thanks to Hans's comprehensive instructions, assembly did not cause the slightest difficulty. The controller already had the latest firmware, and after adjusting the contrast of the LCD display, everything worked like a charm. I made an output transformer for 9 volts. The output power was slightly underestimated, but if you use 10.5 volts, the output power is from 3 to 7 watts. When using a wire frame for the 14 MHz range, 9 V power supply and an output power of about 3 watts, reports from Europe are very good in FT8 and FT4. I am very pleased. Many thanks to QRP LABS and Hans personally for an excellent product!
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a soldering station option
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Lidiette Lacalle
Daniel Conklin
Peter HB9EBE
UPNORTHOF48 :
Udo Die?elberg DF4BJ