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Re: QMX mid band build - Continuity between A and B points
If you do make another order from qrp-labs.com,
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In addition to a few extra bs170 and toroids, buy the
$8.50?
50-ohm 20W QRP HF Dummy Loadvery inexpensive and very useful.
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If you like building kits consider:
$40
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Hans has a video on how to tweak the toroid coils for maximum power.
He uses a scope,? but if you do not have a scope the? above device will read out watts.
It does not matter if it is accurate.? It only matters in determining if? collapsing winding? ?is better than spreading winding.
The above device can be used for that measurement.
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If you are into qrp from remote sites the following
kit tuner was nice:
$45
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stan ag5vh
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Re: QMX mid band build - Continuity between A and B points
Wind toroids using the chopstick method others have recommended.
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Only wind toroids over carpet floors.? Inevitably, you and everyone else will drop them.
They are ceramic and will shatter if you drop them on a tile floor.? Hans buys them in? the thousands, you will not find replacements easily.
If you have a reason to make an extra order from qrp-labs.com buy some extra from the spar parts section.
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Those 47uh axial are more delicate then similar sized resistors -bend leads without applying pressure to body.
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Everybody including me have been fixated with heat dissipation of the bs170.? Don't bother with extra heat sinks.
Some of the problems with? damaging the bs170 was from very early software versions.? Newer software versions
have high SWR protection.? Just do not disable the SWR protection.? ?The heat is dissipated thru the leads and not the plastic.
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Some of the assembly has to be done in the exact order.? Solder has both an electrical, and mechanical purpose.
If you solder before everything is aligned? it will not end well.? I am referring to the connectors on the two power boards,?
and the connectors that extend thru the optional case.? ?
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You have one chance to bend the leads of the encoder in the correct direction- which is probably opposite of what you would think.
I think I just soldered scrap wire to make the connection?
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stan ag5vh |
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Re: Question about bands for "50W Amp for QCX-series"
Hans has posted design info somewhere on its max useful frequency. It's limited by the inexpensive power transistors.?
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It's also a class C design, not suitable for SSB.?
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Note also the low pass filters need larger toroids and wire than the qrp filters qrp-labs sells. A few folk have built theirs to use external low pass filters, or even cascading a second external one.?
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Curt
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Question about bands for "50W Amp for QCX-series"
What is the? highest? frequency for the 50 watt amp ?
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When the 50 watt amp came to market it was when the QCX was out.
I have built the QCX and the documentation says it can do "single band, 160, 80, 60, 40, 30, 20 or 17m"
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Since then Hans has come out with the QMX - of which I have built both the high and low band version.
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I have recently finished the 50 watt amp.? The lowpass filter section matched the needs of the QCX.
I have been using the amp with my low band QMX.
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My question :? Can I use my 10meter QMX with appropriate lowpass filter with the 50 watt amp.
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Can someone explain what is the limiting factor?
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I very much appreciate Hans'? qrp-labs.com? I have learned a lot.
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stan? (ag5vh)
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QMX mid band build - Continuity between A and B points
Hello fellow hams,
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I started my QMX build today. I followed all the steps and I did all the checks mentioned in the instructions.
Also checked every solder joint before proceeding to the next one.
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After building, checking and soldering T501, I checked the continuity between the A and B points as per manual.. and there is continuity.
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Any advice on how to troubleshoot? Any probable suspects?
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Thank you!
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Pedro F4JAW |
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Re: QMX+ Low Image rejection at 160m,
Hello Trevor If you look closely at it with some optical magnification you'll see that there already are thermals. And they're on all layers. Just that with 6 layers and thermals every 90° that means up to 24 thermals per ground point.? 73 Hans G0UPL On Thu, Sep 26, 2024, 16:42 Trevor Shackleton via <trevorshackleton=blueyonder.co.uk@groups.io> wrote:
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Re: QMX+ build: so close, and yet....
I'm pretty sure I did add that jumper....but that doesn't mean it's right :-D I will check it! On Thu, Sep 26, 2024, at 10:37, Greg McCain via groups.io wrote:
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Re: Production seems to have slowed significantly
Thanks for the reply Hans.
I just really hope I get it before the snow hits, and in Canada that could be tomorrow for all we know hehe. Damn labour laws .. Can you tell all employees all hands on deck until I get my order shipped, and also stop innovating until then ? I never take leave(unless forced), because when I come back there's just too much work waiting for me, and I've forgotten how things work (Kind of like a vacation hangover). ?
These were my observations.?
The average change of my position between August 7 - August 28 (21 days) was ~ 14 per day The average change of my position between September 6 - September 26 (20 days) is ~ 7.27? That's close half of August's output so far... |
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Re: Using .33mm/AWG#28 for everything in the QMX+?
I’m taking Hans at his word that “… we'll switch to 0.33mm for everything.“ Even though the photo in the assembly manual shows the thicker wire used for the single turn in T507, I used the same 0.33 mm and assembly was easier.?
I am at the point of switching tips and temperature to work on the back panel connectors, so I have a while to go before I can apply power and see how well my build works. It sure looks neater than my last one!
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Joe KA1ZNA |
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Re: QMX+ build: so close, and yet....
I'm afraid I must say that I don't know yet! I was only using a dummy load, in my basement. I don't have an actual shack in my house -- I'm all portable, all the time -- and I reached this particular juncture at 2300 local time! :-D It's a good question, though, and another thread to pull on. I will see if I can make time this evening to actually get an antenna up and see what/if I can hear. On Thu, Sep 26, 2024, at 09:11, Ian G4GIR wrote:
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Re: QMX+ build: so close, and yet....
开云体育Michael,
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Is it receiving? If not is the link fitted at the Aerial socket?
If all bands exhibit no output and all sweeps are up the swanny.
My guess is CLK2 is missing.
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I had the same problem.
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73
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Ian G4GIR
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Re: QMX+ build: so close, and yet....
Jeff, I have no doubts at all about that last part. Anything not working here is on me and my relative noviceness! The kit is great and the instructions (mostly) very clear! T501 And L502 make sense as starting points. Thank you. Just needed a thread to start pulling on. Michael WD0OM On Thu, Sep 26, 2024, at 05:45, Jeffrey W Moore via groups.io wrote:
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Re: QMX+ Low Image rejection at 160m,
Thanks Hans,
Great kit with excellent support. I look forward to the firmware updates in due course, appreciating that they take time to develop and test.
As an aside I do wonder if you considered adding thermal reliefs on the ground plane connections (on all layers). From experience they make reliable soldering (and a better chance of successful rework) much easier. I would have thought that the tiny increase in inductance would be insignificant at HF.
73 Trevor G6PSZ |
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Re: QMX+ Low Image rejection at 160m,
Hello Trevor 160m image rejection is a known issue and I will fix it as soon as I have done the SSB firmware update. It's not a hardware issue, it's firmware. If all the other bands are correct then you don't need to worry! 73 Hans G0UPL On Thu, Sep 26, 2024 at 3:12?PM Trevor Shackleton via <trevorshackleton=blueyonder.co.uk@groups.io> wrote:
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QMX+ Low Image rejection at 160m,
Hello,
My newly built QMX+ is showing poor image rejection in the test suite, but only when for 160m, other bands look OK.
The image at 160m indicated -3.7, with both wanted and image around -16.
Looking at the Test ADC I/Q, the two signals show almost in phase when they should be 90deg apart for quadrature (other bands show quadrature as expected). The Q waveform is?
only about half the amplitude of the I waveform (again only on 160m, other bands having equal amplitude as expected).
I suspect both the above are different views of the same issue, but I am not sure where to look to further investigate the cause.
Any suggestions appreciated.
Best regards Trevor G6PSZ
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kf7rcm@yahoo.com
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