Re: #qmx video: 52 tips for building your QMX successfully
#qmx
Just one more comment on the excellent "52 tips for building your QMX successfully" youTube video: With regard to the BNC connector, if you test its output to ground, you will see a short even though there is no actual short on the BNC.? That's because T507, the VSWR Stockton bridge transformer, has a winding that goes directly from the output to ground.? Either just inspect the BNC connections carefully for any shorts or mount the BNC before mounting T507.? Note that the pad from the hot side of the alternate SMA pads is very close to one of the ground pads of the BNC so this is good to carefully inspect.
-Steve K1RF
------ Original Message ------
Date 8/27/2023 10:14:59 AM
Subject Re: [QRPLabs] #qmx video: 52 tips for building your QMX successfully
Hans says it’s best to do it as he shows in the video to keep the boards properly oriented. Looked really easy to do the way he demonstrated. It’s an ongoing process of finding the best solutions and updating the manual.?
Ron So to clarify - The manual at Rev H currently says to burn or drill out the center of the spacer nuts on the power board - That is no longer recommended according to the video?
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Re: QMX Shipped, panic stage
#qmx
Hi Billy, my QMX worked just fine from the first power up.! There are still a few bugs that Hans will smooth out over the next firmware updates.? AGC, eratic volume control...to mention a few..? ?but the rigi is a great piece of engineering,? fully useable. and will only get better. best regards Scotty
On Thursday, 31 August 2023 at 16:05:53 BST, Ken W4KAC <oldjoeclark@...> wrote:
Just take your time Billy.? I spent about an hour a night for nearly a week.? QMX #332 worked right off the bench with no problems. Go slow and double check everything as you go so there is no doubt.? ?I have made many CW contacts with it since late July including every contact for the NAQCC letter challenge, and the NJQRP Skeeter Hunt this past Sunday.? Chased lots of POTA and SOTA and had some ragchews with it in the meantime.? Great radio, and I can't wait to hit the summits with it as the wx cools down.? Good luck with yours.
73 Billy, and many thanks to Hans!!
Ken, W4KAC
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Re: 6 and 8m QDX prototype
This prototype can be used only on 6m! 6
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On 31 Aug 2023, at 15:03, Afghan Kabulldust via groups.io <kabulldust@...> wrote:
? Actually I stuffed up again. The 8/6m QDX LPF Is this? 6
On 31 Aug 2023, at 14:30, Afghan Kabulldust via groups.io <kabulldust@...> wrote:
? Schematic that was missed off last email
Next I’ll send the 80m only QDX 6 On 31 Aug 2023, at 14:18, Kabulldust <kabulldust@...> wrote:
<image0.jpeg>
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Bob, Jim, et al,
Further to the 8/6m prototypes I previously posted, I’ll now post the details of an 8m only prototype.
Schematic
Analysis
Implementation
BPF is 11t on an T50-6, squashed up so probably 12 loosely wound may do the trick and a 30pF cap
RF Filter sweep
TinySA measurement
Sent from my iPhone 6
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Pacific Antenna also offers a "Mini SWR Indicator Kit" for $5. Works great.
73 Kees K5BCQ
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Re: QMX Shipped, panic stage
#qmx
Just take your time Billy.? I spent about an hour a night for nearly a week.? QMX #332 worked right off the bench with no problems. Go slow and double check everything as you go so there is no doubt.? ?I have made many CW contacts with it since late July including every contact for the NAQCC letter challenge, and the NJQRP Skeeter Hunt this past Sunday.? Chased lots of POTA and SOTA and had some ragchews with it in the meantime.? Great radio, and I can't wait to hit the summits with it as the wx cools down.? Good luck with yours.
73 Billy, and many thanks to Hans!!
Ken, W4KAC
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Re: QMX Shipped, panic stage
#qmx
Billy, my QMX worked properly from the moment I fired it up. 100% smoke free! Just some minor screen issue that was my fault, and I soon corrected. One of my friends, who ordered a QMX kit two or three weeks ago, got his assembled and running last week, enjoying every step of the process.
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Re: 6 and 8m QDX prototype
Actually I stuffed up again. The 8/6m QDX LPF
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Show quoted text
On 31 Aug 2023, at 14:30, Afghan Kabulldust via groups.io <kabulldust@...> wrote:
? Schematic that was missed off last email
Next I’ll send the 80m only QDX 6 On 31 Aug 2023, at 14:18, Kabulldust <kabulldust@...> wrote:
<image0.jpeg>
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Re: #qmx QMX and waste heat from the finals
#qmx
Before making a radical change to the PA transistor (BS170s) thermal design it is necessary to fully understand the the thermal parameters.? As Hans ha pointed out:
- The six layer board conducts heat very well and is designed with lots of copper in each of its layers.? You may of noticed how much harder, time/temperature, it is to solder parts than the QCX and QDX kits.
- Under the flat surface of the BS170s is a large heat sinking layer.
Background:
? ?BS170 Thermal Resistance
? ? ? ? 220C/W? ?(package only)
? ? ? ? 175C/W???(plated through-holes)
? ? ? ? 145C/W???(plated through-holes and?0.25?inch sqr ?per lead)? With the multi layer board this is probably equivalent.
It appears that the thermal path from a TO-92 (BS170) package is lowest through the pins. This is demonstrated by the significant improvement to 145C/W with good pin heat sinking. (From my investigations it appears that more than 50% of the conduction is through the pins). FYI conductivity of copper is ~400x that of epoxy.
With a fast electrical transient thermal capacities may attenuate any observable rise outside the transistor chip before it fails.
Adding an additional structure under the transistors is questionable:
? ? ? ? Added interfaces to between the transistors and the PC board/case primary heat sink
? ? ? ? In the cramped area of the heat sink there will be little air flow.
? ? ? ? I would strongly recommend against adding anything between the pins and the board.
Test
Good engineering practice mandates measuring the temperature of the current heat sink under the BS170s and comparing the temperature of the proposed heat sink.? Must be done in a full assembled QMX.?
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Re: QMX Shipped, panic stage
#qmx
Hans,
Well, you did it.
- I will carefully read the messages from now on - many have some germ of good info.
- Right, why waste time posting when you have better things to do.
- Telling my self about that repeatedly.
- Watched it three times already. Read assembly instructions three times. Read operating manual twice.
- Right, it is my baby! And i will take good care of it.
- How in the world could I forget that. I AM A TEXAN - enuf said.
Thank you very much, Sotty I bothered you with this.
Billy (N5SE)
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Hello Billy
1) You're reading the wrong messages. There have also been several nice reports of success stories.?
2) You also need to remember that all mailing lists have an inherent negative?bias, in so far as people are far more likely to post about a problem they are looking?for help solving, than they are when everything is fine. And rightly so, since?with 7,541
members here on this group, if everyone posted something when they were successful, and the fact we shipped an average 800+?orders per month in the last 6 months, many of which contain multiple kits, we'd soon be overloaded with emails. So keep the misery
posts in perspective.?
3) Bear in mind the only known issue is that the Q103/Q104 transistors on the 5V SMPS board are a little close together and due to manufacturing tolerances, a proportion of boards have unfortunately got a solder bridge between the two drains; HOWEVER,
we are already testing all shipped boards for this fault and correcting it pre-shipment if we find it.?
4) Watch my "52-tips" video? while waiting for your QMX to arrive.?
5) If you take care and observe all the precautions mentioned, there is a VERY high probability of success. Remember, component and manufacturing failures are rare. It's largely in your hands!
6) You're a Texan. Texan's can deal with anything.?
On Thu, Aug 31, 2023 at 4:48?PM N5SE < bwmoore@...> wrote:
Hans,
Received message my QMX shipped today. Thought I would be excited. But instead, I am reaching panic stage. With all the misery I have read in the last week, I figure my chance of ever getting it to work is somewhat less than zero. Guess I am looking for a little
assurance.
-- Billy (N5SE)
N5SE
Billy Wayne Moore
7066 Shady Knoll Ln
Willis, TX 77318-6324
Phone: 936-537-2975???
-- N5SE
Billy Wayne Moore
7066 Shady Knoll Ln
Willis, TX 77318-6324
Phone: 936-537-2975???
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Re: 2nd QMX Build and it wont power on and an update on my old unit...
If you want to send it to me, I’m sure I can help out. ?At this point I’ve fixed over 20 QMX rigs. ?Contact me for details of where to send it.
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Re: 6 and 8m QDX prototype
Schematic that was missed off last email
Next I’ll send the 80m only QDX 6
toggle quoted message
Show quoted text
On 31 Aug 2023, at 14:18, Kabulldust <kabulldust@...> wrote:
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Re: #qmx QMX and waste heat from the finals
#qmx
I believe Chris is correct.?
Me personally, I have never added a heatsink to any of my QCX, QCX+, QCX-mini, QDX and QMX, and I have yet to burn up any BS170s other than that night earlier this year when I lay in bed half-asleep at 4:30am in the morning listening to a massive thunderstorm crashing around, failing to calculate which flash belonged to which boom and therefore was it coming or going, and failing to quite motivate myself to get out of my nice warm bed and haul myself up to the lab and unplug the antenna coax.?
In my opinion you're looking for solutions to a non-existent problem. On the other hand, it's harmless, and if it makes you happy, well, live and let live ;-)?
On Thu, Aug 31, 2023 at 5:14?PM Chris KB1NLW via <chrisrey1= [email protected]> wrote: Before making a radical change to the PA transistor (BS170s) thermal design it is necessary to fully understand the the thermal parameters.? As Hans ha pointed out:
- The six layer board conducts heat very well and is designed with lots of copper in each of its layers.? You may of noticed how much harder, time/temperature, it is to solder parts than the QCX and QDX kits.
- Under the flat surface of the BS170s is a large heat sinking layer.
Background:
? ?BS170 Thermal Resistance
?220C/W??(package only)
175
°
C
/
W
?(plated through-holes)
145
°
C
/
W
?(plated through-holes and?
0.25
i
n
c
h
2
?pad per lead)
|
Sorry iPhone sent by a light touch of finger by mistake.?
Bob, Jim and others,
Here’s a pic of the 6m prototype. Firstly, I printed my own T50-0 toroids; secondly, you’ll note the T50–6 in the BPF; thirdly, you’ll note the binocular is not the glossy 43 mix rather a BN61-202; and, lastly, the Tx phase splitters is also a T37-61.? Output transformer is wound for 12V as a Really Weird Twisted Sisters Transformer (search for my previous posts in io).? Attached: Design schematic for LPF Analysis of design.?
Implementation Pic of prototype? T50-0 printed toroids T37-17d can be used: Input L 10t T37-17 Trap L ? 9t T36-17 BPF L 11t T69-6? BPF C ?22pF
Measurement: Rf Filter sweep ? 6m 8m
TinySA both done with 35dB in-line 6m spectrum - quite good.? 8m spectrum the 8m spectrum is borderline
?but after more squeezing/splaying of LPF turns may improve harmonics
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Yes try GPT4 its much better, and as from yesterday they are offering an Enterprise edition that keeps all company data private and safe.
Its loads better than chatgpt but costs $20 a month, well worth it.
But, everything has crashed as the USA came online, probably due to the new enterprise edition.
Paul DJ0CU.
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Re: #qmx QMX and waste heat from the finals
#qmx
Before making a radical change to the PA transistor (BS170s) thermal design it is necessary to fully understand the the thermal parameters.? As Hans ha pointed out:
- The six layer board conducts heat very well and is designed with lots of copper in each of its layers.? You may of noticed how much harder, time/temperature, it is to solder parts than the QCX and QDX kits.
- Under the flat surface of the BS170s is a large heat sinking layer.
Background:
? ?BS170 Thermal Resistance
?220C/W??(package only)
175
°
C
/
W
?(plated through-holes)
145
°
C
/
W
?(plated through-holes and?
0.25
i
n
c
h
2
?pad per lead)
|
Re: QMX Shipped, panic stage
#qmx
Hello Billy
1) You're reading the wrong messages. There have also been several nice reports of success stories.?
2) You also need to remember that all mailing lists have an inherent negative?bias, in so far as people are far more likely to post about a problem they are looking?for help solving, than they are when everything is fine. And rightly so, since?with 7,541 members here on this group, if everyone posted something when they were successful, and the fact we shipped an average 800+?orders per month in the last 6 months, many of which contain multiple kits, we'd soon be overloaded with emails. So keep the misery posts in perspective.?
3) Bear in mind the only known issue is that the Q103/Q104 transistors on the 5V SMPS board are a little close together and due to manufacturing tolerances, a proportion of boards have unfortunately got a solder bridge between the two drains; HOWEVER, we are already testing all shipped boards for this fault and correcting it pre-shipment if we find it.?
4) Watch my "52-tips" video? while waiting for your QMX to arrive.?
5) If you take care and observe all the precautions mentioned, there is a VERY high probability of success. Remember, component and manufacturing failures are rare. It's largely in your hands!
6) You're a Texan. Texan's can deal with anything.?
On Thu, Aug 31, 2023 at 4:48?PM N5SE < bwmoore@...> wrote: Hans,
Received message my QMX shipped today. Thought I would be excited. But instead, I am reaching panic stage. With all the misery I have read in the last week, I figure my chance of ever getting it to work is somewhat less than zero. Guess I am looking for a little assurance.
-- Billy (N5SE)
N5SE
Billy Wayne Moore
7066 Shady Knoll Ln
Willis, TX 77318-6324
Phone: 936-537-2975???
|
? Bob, Jim and others,
Here’s a pic of the 6m prototype. Firstly, I printed my own T50-0 toroids; secondly, you’ll note the T50–6 in the BPF; thirdly, you’ll note the binocular is not the glossy 43 mix rather a BN61-202; and, lastly, the Tx phase splitters is also a T37-61.? Output transformer is wound for 12V as a Really Weird Twisted Sisters Transformer (search for my previous posts in io).? Attached: Design schematic for LPF Analysis of design.?
Implementation Pic of prototype? T50-0 printed toroids T37-17d can be used: Input L 10t T37-17 Trap L ? 9t T36-17 BPF L 11t T69-6? BPF C ?22pF
Measurement: Rf Filter sweep ? 6m 8m
TinySA both done with 35dB in-line 6m spectrum - quite good.? 8m spectrum the 8m spectrum is borderline
?but after more squeezing/splaying of LPF turns may improve harmonics
|
Re: QDX - protection of BS17O PA
nvm, I see someone else started a thread with that exact question
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I have used it to generate outlines of Python code. It speeds up the initial process when I don’t know what libraries I need to use. My first try was a 3D water fall plot from a wav file of passing APT weather data.?
At work I have been using it to generate templates for corporate documents. Part of my job is to figure out problems when we have a company emergency and we don’t have a person in staff qualified to fix them. This week I have had to generate a departments SOPs. Getting a template from chatGTP and then editing it to fit our processes has greatly sped up the process.?
It is really important to understand it’s very big limits. Take a subject where you have some expertise and probe it’s knowledge. It is often very wrong! I spent 10 years making holograms as an example. If you ask it simple questions about the process it spins very inaccurate responses. It doesn’t know what it doesn’t know.?
--
Colin - K6JTH?
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N5SE
Colin Kaminski