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Re: QMX short over antenna jack #build #qmx #solder

 

Rico, please read the QRP Labs Wiki document about the PCM1804.
ADC I/Q shows no real RX signal but strong noise. The most probable place for this noise is the PCM1804 itselve.
To check this please follow the Wiki doc.
73 Ludwig
Re: Solder

 

FYI:
The US military requires leaded solder to prevent the formation of tin whiskers.?
Re: QDX Died shortly after arrival #qdx

 

Perhaps, but the two low band QDX's are doing fine with about the same number of hours and using the same antenna, etc. on 20 meters.
Re: Release of version 1.2 of ABS solution for QMX+ (Automatic internal antenna tuner, internal battery and internal speaker with audio amp) #ABS #ATU #PSU #QMXplus

 

As far as I know the first group buy is closed, participants paid their shares and are in the process of getting their kits.
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The best way is to contact Cal (AD8Q) and Stan (KC7XE) by email.
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You can find more group buy discussion (although it is quite outdated at this point) in this thread:
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--
73,
Sardar (AC8L, 4K6SA, VA3DUA).
Re: QDX Died shortly after arrival #qdx

 

The fact thast you've now smoked two radios I would be very concerned about some fault with either the power supply, antenna, swr meter and/or dummy load.
QDX Died shortly after arrival #qdx

 

The 12v QDX HB that I ordered pre-built arrived Monday the 23rd of Dec. It is replacing the rev. 5 QDX HB that I bought pre-built in May '23 that has developed an aversion to heat - it stops TX after it gets warm. I think a SMT component is lifting as nothing seems to be an issue otherwise (Jeff Moore looked at it three times).
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I tested the new one into the dummy load at 11 volts (how I operate these) and confirmed nice power out on all bands with 3.7 watts on 10 meters via "tune". On FT8 into an antenna at an SWR of 1:1.2 I was seeing 3.4 watts out. It worked fine for two hours the first afternoon and another hour the next afternoon when I noticed the power out rose to 4.0 then dropped to 3.8 on one CQ call.
On the next cycle the magic smoke escaped, JTDX offered to reconfigure because the radio had disappeared, and I saw that the QDX was drawing the max of 1 amp at 5 volts from the Drok buck/booster supply.?
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I cannot see what burned nor where the smoke came from. I can smell the smoke stronger on the top of the board than on the bottom this morning. I tested the Drok with the QDX LB and it is working fine. I then connected the smoked QDX HB to the Drok and it again hit the amps limit of 1 and volts dropped to 5.?
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I am rather disappointed in the three hour life of this new QDX and don't know where to start looking for the short/fault - source of the smoke. I submitted a support ticket today, but hope no one is reading them now!
Re: Happy holidays!

 

开云体育

Happy Holidays to all you rascals finding the best value in ham radio today!

Here’s a crescendo for ya!


Paul Wamble
K5EBP?
214-405-5876 cell?


On Dec 25, 2024, at 10:01?AM, Robert AG6LK via groups.io <amrmedic@...> wrote:

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Happy Holidays to all and may 2025 be happy and prosperous to all.

Re: Solder

 

Don, if you dig into the details, 60/40 is better for tinning, since it has a plastic range, and 63/37 is better for everything else, since it does not. Yes, this thread sent me that far down the rabbit hole. :)
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Merry Christmas & 73 de AI7SY

Re: QMX short over antenna jack #build #qmx #solder

 

Hi there,
I've run some tests now.
Measured the output power with almost 5W at input voltage of about 9.1V into a dummy load.
I tested for continuity on all the coils. The soldering here seems to work fine.
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I post some pictures of the test-screens...
Hopefully these pictures lead to the problem somehow
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LPF
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image sweep
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RF filter
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audio filter
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test ADC I/Q
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Re: Solder

 

On Wed, Dec 25, 2024 at 12:43 PM, stan timmerman wrote:
But probably - when no one is looking - you will pull out the 60/40 (lead) solder you have been hiding from the goverment.
Or even better, 63/37 (eutectic) alloy with RMA flux core.
73, Don N2VGU

Re: WSJT-X on Raspberry PI 3B and QMX+ unstable

 

It could be a faulty USB cable, but I would check your antenna from end to end and the transmission line first. I was having some strange issues recently and discovered my counterpoise had fallen into the snow.
--
73, Dan - W2DLC

WSJT-X on Raspberry PI 3B and QMX+ unstable

 

The setup of this combination has been working just fine with FT8 and WSPR for a while. All of a sudden, tx stopped working while rx still works, including bandhopping. After resetting and restarting sometimes both tx and rx work, then. again suddenly tx quits. Any advice? Could it be a falty USB-C cable?
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Hiroki AH6CY
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Re: Solder

 

I would not agree to the statement that it won't work with lead free solder.
You should use a soldering station anyhow for the multilayer boards and with a good alloy there is no problem.
I'm using Stannol HS10 Sn95,5Ag3,8Cu0,7 which is so far the best lead free solder I used and I tried quite a few.
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If you use a low cost alloy without silver it makes things more complicated.
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KR
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Dirk

Re: Solder

 

The water spec is common for what's also referred to as deionized water in industrial applications. We had a plant at pppl.gov that made thousands of gallons, since we used it to cool a number of? of high power devices like 8974 2.5 MW tube amplifier modules...
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While that NASA soldering spec dates from 2006, SN60/SN63 remains to this day in the NASA supply chain. Aerospace material suppliers still sell it. SAC305 (tin-silver-copper) is the current recommended replacement, at 4-5 times the cost.
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Re: QMX and FLDigi - MFSK modes

 

Has this been fixed or are these the same modes that work? Is there a way to do RTTY?

Re: Solder

 

Hint for new builders:
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If you? build with lead free solder your radio will probably not work.
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Maybe if you? have a lot of experience and? very nice equipment you could make lead free work.
But probably - when no one is looking - you will pull out the 60/40 (lead) solder you have been hiding from the goverment.

Re: Release of version 1.2 of ABS solution for QMX+ (Automatic internal antenna tuner, internal battery and internal speaker with audio amp) #ABS #ATU #PSU #QMXplus

 

If anyone is building more than 1 and is willing to sell the other one, I'd love to volunteer! Interested in the full monty — the board with ATU, battery, and speaker. 73, Merry Christmas,
Randy K7RAN
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Re: Should I be disappointed?

 

On 25/12/2024 11:04, David Wilcox K8WPE via groups.io wrote:
There should be a diagnosis title for that condition
Now then Dave, a chance for you to write a scholarly article about this and submit it to The Lancet or such. As a doc, you have the qualifications. Maybe they'll publish it and it can become known as Wilcox Syndrome. ;-)

Andy

Happy holidays!

 

Happy Holidays to all and may 2025 be happy and prosperous to all.

Re: Should I be disappointed?

 

On 25/12/2024 13:22, terompet via groups.io wrote:
a few db of gain can make a difference.? I am looking at the 10 watt amplifier kit.
As Greg says the QRP Labs 10 Watt amplifier is not suitable without modifications to reduce its gain. Basically that is best done by removing most of its circuitry. (Or the QMX PA.)

And, following the theme 3 Watts to 10 Watts is just over 5dB, maybe worthwhile but you will want more and more.
On the other hand if you don't feel you will live long enough to do it with 3 Watts go for 1.5KW and then give up radio:-)

73 Alan G4ZFQ

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