Weak receive on QMX version 1 - New build
I finally got around to building the version one QMX I purchased last year at FDIM.? The build went well and I thought I has no problems, but it appears to be weak on receive.
I have 4.95+ watts out
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Gary - W0MNA
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#116765
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Re: 5W mini transmitter for presetting the ATU
Besides being amused by the hard way approach, some thoughts.
The test transmitter has to put out the needed power on all bands
of interest.? ?Easier said than done for many.
I has to be robust,
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ajparent1/kb1gmx
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#116764
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Re: Precision IC socket - QMXable
The downside of the connector is to degrade the heat flow through the leads - a major element of the heat sinking.
A couple of days ago I noticed power out dropped to 2W.? It took *one hour* to open
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Chris KB1NLW
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#116763
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QMX (hi band) new build does not power up
I built a QMX low band in the summer with no issues. So, I bought a high band kit for Christmas and after building it, I see nothing. No bootloader, no start, nothing on the display. Comparing the
By
2e0gwb@...
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#116762
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Re: Precision IC socket - QMXable
No clue why you would do this (I have much experience of sockets getting problematic over time) -? but enjoy . .
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Bruce Akhurst
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#116761
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Re: 5W mini transmitter for presetting the ATU
hi
Forgot:
ATU-10 can tune less than a Watt.
73 de muhsin TA1MHS
By
Muhsin TA1MHS
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#116760
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Precision IC socket - QMXable
Hi
Quick BS170 change
73 de muhsin TA1MHS
By
Muhsin TA1MHS
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#116758
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Re: 5W mini transmitter for presetting the ATU
Sam, et al,
An SWR bridge will protect the transmitter, but it will NOT pass the full 5 W through to the ATU. Probably closer to half that. If the ATU truly needs 5 W, then this trick won't
By
Daniel Walter
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#116757
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Re: QMX Voltages 9 vs 12 vs 13 How to do this?
Jim, a buck converter with current limiting sounds like a great idea for these QRP Labs radios!
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Leigh KG7WED
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#116756
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Re: clock contrast mod
#clock
Thanks Bruce. Good to know. from the schematic I could not see how I could have got it wrong.
Onward and upward. :-)
--
regards,
Bryan, N0LUF
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Bryan Curl
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#116755
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Re: 5W mini transmitter for presetting the ATU
Hi
From the same designer of ATU-100 pls try ATU-10.
https://github.com/Dfinitski/ATU-10-10W-QRP-antenna-tuner
I'm using this tuner for a long time
perfect for QDX, QMX, 705, Hermes Lite 2 vs
73
By
Muhsin TA1MHS
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#116754
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Re: QCX CAT Questions ....
#cat
#qcx
I have used RF shield paint for some projects, but on the QCX, ?I had no issues - 3 mm particle board worked just fine.
--
73, Bernie, VE3FWF
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Ham Radio <bernard.murphy@...>
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#116753
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Re: QCX CAT Questions ....
#cat
#qcx
That's it Bernie! Thanks so much! BTW - I like your laser cut enclosure! Question - is it foil wrapped inside for RF/EMF? insulation? I've thought of using other materials for enclosures but wondered
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Rob - KC4NYK
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#116752
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Re: Excess QRP LABS For Sale
Is the QMX assembled or still as a kit?
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N1EDC
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#116751
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Re: AB4IQ's email address
That's OK. They could just reply to you privately here by clicking Reply and then choosing sender:
73, Mike KK7ER
By
Mike KK7ER
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#116750
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Re: clock contrast mod
#clock
Even with 220K the contrast adjustment is super sensitive
the centre holes are for the jumper or the outer holes for the resistor
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Bruce Akhurst
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#116749
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Re: clock contrast mod
#clock
Looking at the pcb the top 2 holes are joined with a trace. the 3rd hole has a trace running off somewhere and the bottom hole, I can't tell. If it has a trace its on top side.
I tried using hole 2-3
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Bryan Curl
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#116748
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Re: troubleshooting QMX rev 2 high bands transmit
#qmx
#transmitpower
#troubleshooting
Thank you everyone for the tips. I redid the solder on connection C on T507 and voila¡ no more protection mode. Now to the diag fine tune.
I appreciate all the support.
73, Eduardo, KC8R
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Eduardo Carvalho Neto - KC8R
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#116747
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Re: 5W mini transmitter for presetting the ATU
Hello Samantha and Bojan,
thanks for your tips.
Switching the ATU to 1W seems to be a good solution. However, I don't have a programmer, and a good 30€ for a PICKIT 3, well...
Samantha, thanks for
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Axel Kohlgrueber
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#116746
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Re: QMX no Rx after a few days of operation
(Sorry, I meant to say IC402, not IC403.)
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Max VK2XOR
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#116745
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