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)
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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???
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? 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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Re: QDX - protection of BS17O PA
nvm, I see someone else started a thread with that exact question
|
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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QMX Shipped, panic stage
#qmx
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???
|
I wonder how many of you are using chatGPT/GPT4 etc to assist in various things like Ham radio, programming or work?
Paul DJ0CU G4ADF?
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Re: QDX - protection of BS17O PA
The finals don't need any protection.
As Jim says, just follow the science of what you are transmitting into and make sure all your antenna connections are sound.?
I would certainly recommend some antenna matching unit, I use a home brew Z-match here.
Wild SWRs will do for every transmitter I own, this was drummed into me early on.
73s Ted
2E0THH
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Re: QMX: Kit Build complete - My observations
Hi Steve
Hi all - mine is also complete and working extremely well. Amazing kit and service from Hans so a huge thank you there. Built for 12V, 5W out on all bands except 20m where it's 4W. I made lots of mistakes along the way and the board survived my fixes so that's saying something.
Thanks Steve! Nice to hear of your success.?? ? WSJT-X frequency cal tool shows a df of less than 0.5 Hz - how is it so good??
It's what you get when we put in a 25 MHz TCXO frequency reference which costs me almost as much as the CPU!
73 Hans G0UPL
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Re: Power supply recommendation wanted
If you're looking for more info on those HP and Agilent power supplies, it's now on the Keysight website. Agilent, which was originally spun off from HP when the parent company chose to focus on its computer business, spun off the general purpose test equipment business to concentrate on the medical market and a few other related vertical markets. Keysight is now the company that's most like the original Hewlett-Packard; they make oscilloscopes, spectrum analyzers, logic analyzers, power supplies, signal generators, multimeters, LCR meters, and other things like that.
On Thu, Aug 31, 2023 at 8:45?AM Dave Edwards < kd2e@...> wrote:
I worked many years for HP/Agilent, so you can guess my
suggestion!! Fortunately, it's just a power supply, so not priced
crazy. You can also find cheap (garbage) but workable imported
jobs on Amazon....but, 'ya get what 'ya pay for!
Look for a nice, working, HP 6216A on ebay. And, note that it is
a part of a series (621XA)...various voltages and currents. They
stack, you'll want to get others in the series. They are tiny,
analog meter and adjustable voltage and current limit. My favorite
for watching what an unknown circuit is doing.
A generation newer and more advanced is another rock-solid job,
the HP/Agilent E3615A. Digital reading of current and voltage. Up
to 20 volts/2 or 3 amps (forget which).
Again, there are junky ones out there, but if you want to be sure
of valid voltage/current indications, and DC that is assured of no
spikes, ripple, noise, AC components etc....The HP Agilent ones
are king!!
They are ALWAYS on ebay. But you have to shop. Some are crazy
priced, some are kicked around, cracked, beat up junk.?
But...there are beautiful ones out there as well!!!
I have lots of other HP.Agilent power supplies, as well as a few
B&K ones, but those are the two model numbers that I would
bee-line in on, if I had none!
Good Hunting!!
......Dave? KD2E
On 8/31/23 8:24 AM, Denny WY2A via
wrote:
Sorry Dave. I should have been more specific. I want a test bench
power supply for construction and testing of QRP radios like the
QMX.?
|
Re: Power supply recommendation wanted
I worked many years for HP/Agilent, so you can guess my
suggestion!! Fortunately, it's just a power supply, so not priced
crazy. You can also find cheap (garbage) but workable imported
jobs on Amazon....but, 'ya get what 'ya pay for!
Look for a nice, working, HP 6216A on ebay. And, note that it is
a part of a series (621XA)...various voltages and currents. They
stack, you'll want to get others in the series. They are tiny,
analog meter and adjustable voltage and current limit. My favorite
for watching what an unknown circuit is doing.
A generation newer and more advanced is another rock-solid job,
the HP/Agilent E3615A. Digital reading of current and voltage. Up
to 20 volts/2 or 3 amps (forget which).
Again, there are junky ones out there, but if you want to be sure
of valid voltage/current indications, and DC that is assured of no
spikes, ripple, noise, AC components etc....The HP Agilent ones
are king!!
They are ALWAYS on ebay. But you have to shop. Some are crazy
priced, some are kicked around, cracked, beat up junk.?
But...there are beautiful ones out there as well!!!
I have lots of other HP.Agilent power supplies, as well as a few
B&K ones, but those are the two model numbers that I would
bee-line in on, if I had none!
Good Hunting!!
......Dave? KD2E
On 8/31/23 8:24 AM, Denny WY2A via
groups.io wrote:
toggle quoted message
Show quoted text
Sorry Dave. I should have been more specific. I want a test bench
power supply for construction and testing of QRP radios like the
QMX.?
|
Re: QDX - protection of BS17O PA
The best solution is to use a good, resonant, low SWR antenna. I have made almost 500 contacts with my stock QDX (ver 5) and have had no issues. My QDX is powered by a 12v 1 amp switching supply. Jim WB2LHP
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Re: Power supply recommendation wanted
Denny,
The following are not "Name Brand" that I have purchased and am very happy with the performance:
For a linear supply, I have the following:
For higher current requirements, I use a switching supply that I have not noticed any switching noise (note - I live in a very RF noisy area, so this may not be the same if you are in a low noise area):
Most of the time, I use the?IKococater switching supply.
73
Evan
AC9TU
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Re: Power supply recommendation wanted
Hi Denny, I personally use this one:?
It has a switch which turns off output power (I was surprised to see this was not a common feature on this type of PSU) which is much better than having to unplug connectors or having to remove the input power just to turn off output.
Len? G6YZB
Sorry Dave. I should have been more specific. I want a test bench power supply for construction and testing of QRP radios like the QMX.?
|
Re: Power supply recommendation wanted
Sorry Dave. I should have been more specific. I want a test bench power supply for construction and testing of QRP radios like the QMX.?
|
Re: Power supply recommendation wanted
For what purpose?
rig high power, rig low power, test bench PS? ??
On 8/31/23 7:59 AM, Denny WY2A via
groups.io wrote:
toggle quoted message
Show quoted text
I would appreciate any recommendations for a decent
current-limited power supply. I’d prefer to stick with brands of
known quality, but would appreciate any suggestions you might
offer.?
Denny N2ETZ?
(formerly WY2A)
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Re: QDX - protection of BS17O PA
Hi Bojan,
I've read a number of comments about an adjustable current limiting PS and I am wondering what you and others are using and would recommend.
73 - Jon Halterman - KJ4CRW
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Power supply recommendation wanted
I would appreciate any recommendations for a decent current-limited power supply. I’d prefer to stick with brands of known quality, but would appreciate any suggestions you might offer.?
Denny N2ETZ?
(formerly WY2A)
|
Re: 2nd QMX Build and it wont power on and an update on my old unit...
Even if it seems to be deaf, should I still have audio out of the headphone port of some sort? I do not…
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Re: QMX: Kit Build complete - My observations
Hi all - mine is also complete and working extremely well. Amazing kit and service from Hans so a huge thank you there. Built for 12V, 5W out on all bands except 20m where it's 4W. I made lots of mistakes along the way and the board survived my fixes so that's saying something.
WSJT-X frequency cal tool shows a df of less than 0.5 Hz - how is it so good??
Can't wait for the high bands version and further updates.
73 Steve MW0KST
|
Colin Kaminski
N5SE
Ted 2E0THH
Shirley Dulcey KE1L