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.?
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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.?
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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:
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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)
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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
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Re: #qmx QMX and waste heat from the finals
#qmx
Thanks, Cliff. I don't have any left over from my RPIs, but I found something on Amazon. I'm going to give that a try.
Wayne KB4DSF
On Wed, Aug 30, 2023 at 11:59?AM Cliff < ae5zaham@...> wrote: Wayne,
I had it lying around from a Raspberry Pi 3B that I had put in a different enclosure with different cooling so the heat sink wasn't needed anymore. Wish I had more of them.
Thanks, Cliff. You've been a tremendous help on this. Where did you find the heat sink you have on top of the finals?
Wayne KB4DSF
On Wed, Aug 30, 2023 at 11:41?AM Cliff < ae5zaham@...> wrote: Wayne,
There is just a hole through the plate to hold it in place and a foot that you can't see almost at the left hand edge under the plate the same as the one that is visible on the right hand side. It was made from a piece of aluminum molding that happened to have those two feet in the right place. I may try to put a piece of it under the finals on the QMX, but without the feet, as I'm sure there isn't enough room for the extra height of the feet.
I also added the diode across L14 so hopefully it will be as bullet proof as I can make it and baring operator "destructive" testing should last a long time.
Here's the reference from John Z to the diode "fix" in case you are interested.
The diode simply is in parallel with the 47uH inductor L14, with the
orientation shown in the photo provided by Paul W9AC. Cathode towards
the power supply connection, anode to the transformer center tap.
Any of the diodes he mentioned ?(1N4448, 1N4148, 1N914) will do a fine
job of absorbing the end-of-transmission voltage spike it produces.
I have used a 1N914.
/g/QRPLabs/message/105256
Hey, Cliff. How did you mount the plate under your finals?
Wayne KB4DSF
Wayne Greene
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Re: QMX - smoke - another C107/Q108 failure
Thanks Hans,
A friend of mine recovering from two strokes built the QMX before joining this group (showing all the issues) and it worked to his satisfaction. He is sending it to me as a gift as he doesn’t like digital modes. ?I have the kit I purchased from you (unbuilt yet) at Xenia and was just wondering…. I don’t turn things on and off quickly as that will cause more problems with computers than it’s worth but just had to ask.
Dave K8WPE since 1960 David J. Wilcox’s iPad
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On Aug 31, 2023, at 5:49 AM, Hans Summers <hans.summers@...> wrote:
? Hello Dave
I don't think that is necessary.?
With a lot of effort, messing around with a poor intermittent 12V power supply connection, while simultaneously holding the left knob (power on/off) pressed, I was able to kill the 5.6V zener. But I don't think it is a major risk. You really had to try hard, to do it. On Thu, Aug 31, 2023 at 12:43?PM David Wilcox K8WPE via <Djwilcox01= [email protected]> wrote: In this line of emails does it mean one should not turn the power ON and OFF in rapid succession or even semi quickly because it takes a few extra milliseconds for the power supply controls to do their job?? IE turn on, let it run a few seconds before turning off….. about the time needed to smell or see the magic smoke. ?
Dave K8WPE? David J. Wilcox’s iPad ? What a complete detailed response and education for everyone. I am impressed with your bandwidth and expertise relative to this wonderful QMX product.
Hi hi, bandwidth and expertise? You should ask my family, how often I showered, shaved, even SPOKE to them in the last few months! It's by far the biggest project I've ever done. So yeah I know every resistor and every line of code! I could probably write it all out from my head with very few errors!
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Re: QMX: Kit Build complete - My observations
Hi,
these are my first QMX HW test measurements.
73 Bojan S53DZ
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Re: QMX - smoke - another C107/Q108 failure
Hello Dave
I don't think that is necessary.?
With a lot of effort, messing around with a poor intermittent 12V power supply connection, while simultaneously holding the left knob (power on/off) pressed, I was able to kill the 5.6V zener. But I don't think it is a major risk. You really had to try hard, to do it.
On Thu, Aug 31, 2023 at 12:43?PM David Wilcox K8WPE via <Djwilcox01= [email protected]> wrote: In this line of emails does it mean one should not turn the power ON and OFF in rapid succession or even semi quickly because it takes a few extra milliseconds for the power supply controls to do their job?? IE turn on, let it run a few seconds before turning off….. about the time needed to smell or see the magic smoke. ?
Dave K8WPE? David J. Wilcox’s iPad ? What a complete detailed response and education for everyone. I am impressed with your bandwidth and expertise relative to this wonderful QMX product.
Hi hi, bandwidth and expertise? You should ask my family, how often I showered, shaved, even SPOKE to them in the last few months! It's by far the biggest project I've ever done. So yeah I know every resistor and every line of code! I could probably write it all out from my head with very few errors!
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Re: U3S No Power Troubleshooting
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Re: QMX - smoke - another C107/Q108 failure
In this line of emails does it mean one should not turn the power ON and OFF in rapid succession or even semi quickly because it takes a few extra milliseconds for the power supply controls to do their job? ?IE turn on, let it run a few seconds before turning off….. about the time needed to smell or see the magic smoke. ?
Dave K8WPE? David J. Wilcox’s iPad
toggle quoted message
Show quoted text
On Aug 30, 2023, at 10:33 AM, Hans Summers <hans.summers@...> wrote:
? What a complete detailed response and education for everyone. I am impressed with your bandwidth and expertise relative to this wonderful QMX product.
Hi hi, bandwidth and expertise? You should ask my family, how often I showered, shaved, even SPOKE to them in the last few months! It's by far the biggest project I've ever done. So yeah I know every resistor and every line of code! I could probably write it all out from my head with very few errors!
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Re: U3S No Power Troubleshooting
?KI7MWA
This may help you troubleshoot
To measure? "rf"? I use this circuit and a common dc Volt meter (DVM)
At 10 mHz and 5 Volts and one BS170
Measure at output of C5 with filter removed
?? IF????? R5 is set to measure much over 1.5 V rms at C5 with filter removed?
THEN? one BS170 goes from warm to hot
P = (E^2) / R
(1.5 X 1.5) / 50? =? 0.045 W?? (45 mW)
72 73
John
N3AAZ
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Re: QDX - protection of BS17O PA
Hi Pierre,
my QDXs are built for +12V.
I am using these practices:
- added an antiparallel 1N4148 to L14,
- using a good +12V PS with a 1A current limit (and no higher voltage),
- matching the antenna before using QDX's TX.
73 Bojan S53DZ
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QDX - protection of BS17O PA
Finally what is the best solution to protect the BS170? Solder a 1N4448 or 4148 or 914 in parallel to L14? I read also 2 Zener diodes alongside T1? What should I chose?
73 - Pierre - FK8IH
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Re: QMX - sockets for BS170s
On Thu, Aug 31, 2023 at 12:52 AM, Reinhard Gr?nz wrote:
The QMX will not work without an adapted antenna.
How does it work with a resonant antenna that requires no tuner such as a dipole or K6ARK End Fed??? ? -- Compton VK2HRX Sydney, Australia
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Re: QMX - sockets for BS170s
Thank you all for your helpful input.??
Cliff - I'd be interested to hear how you get on, if you are inclined to let us know.
73
Chris? G4CWS
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Not sure how it will work but would the type C allow the clock to be set by connecting it to a phone/PC?
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David Wilcox K8WPE
Pierre - FK8IH
Compton