Re: Bench power supply for QDX, QMX etc
I have been using the?Korad KD3005D for years now. It has all you need for a nice price (Euro 59) and with a real transformer in it (no switch mode power supply).? 0-30V / 0-5A incl curent linit.? Digital read out and remembers the settings between power cycles.? For example :? --
73 Lex PH2LB?
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Bench power supply for QDX, QMX etc
I'm a bit of a newb.
What bench power supply would you recommend for building kits like the QDX and QMX?
I would prefer to buy a new product (vs used) and if possible like to keep the price to $150US or less.
There are MANY power supplies in this range;? it is hard for me to compare.
If anybody has a suggestion please reply!
Thanks in advance!
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Re: UL3S transmits continuously in RUN mode
Well Andy, I figured it out. Actually I accidentally stumbled onto a solution that causes the UL3S to do what I want it to do.? I've got 13 WPM CW for 1 minute, 30 seconds, then 20 seconds of calibration, about 5 seconds of silence and it repeats.? If anyone else is doing a CW beacon and needs the setup let me know and I'll be happy to share my settings.??
73, Jerry AC5JM
On Wednesday, September 20, 2023 at 04:04:25 PM CDT, Jerry Moyer via groups.io <ac5jm@...> wrote:
I do not want that much downtime.? During 10 meter E-skip conditions propagation can come and go several times in a minute and it decreases the value of having a propagation beacon in the first place.? What I want is 1 - 3 minutes and 50 seconds of CW churning away at about 15 WPM and then at most 10 seconds of calibration.? With a TCXO it surely doesn't need more calibration time than that.? But I still don't grasp the relationships between Frame length, starting time, GPS calibration time, GPS step size, CW speed, and CW message length well enough to make it all work together like I want. It appears to be a complex relationship.? I don't understand how It can work at say 13 WPM but when I increase the speed to 15 WPM without increasing the message length it fails.? I just spent several hours of trial and error and have not been able to figure it out.? I'm just about ready to hook up my Arduino keyer externally instead but I hate to lose GPS frequency sync capability.??
Thanks, Jerry- AC5JM
On Wednesday, September 20, 2023 at 10:13:43 AM CDT, M0RON <eustace.andy@...> wrote:
Progress.?
You also have to take into account the calibration time. If you were to set the calibration parameters to say, 10 060 and frame 02 start 02 it should transmit for your 40 second, calibrate for 1 minute then idle for 20 seconds before repeating.?
Once you understand these 2 menus the rest is easy.?
Andy?
--
The universe is made up of Protons, Neutrons, Electrons but contains only one M0RON.
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Re: QMX Repair - Anyone Interested?
Jim,
Jeffrey Moore has offered to help anyone get their qrp-labs kits fixed. He has the equipment to do it. Shoot him an email.
?
toggle quoted message
Show quoted text
On Sep 20, 2023, at 19:23, Jim Bennett / K7TXA via < w6jhb@...> wrote:
You may have seen a post I did a few weeks ago regarding my QMX kit. After assembling it I discovered the dreaded short between Q103 and Q104. Power has NOT been applied. It is wired for 12 operation. I tried removing 103 but that turned into a disaster. The case came off it it and now I've got an even smaller part to try removing. I'd tried a hot air gun but partially melted the Mic connector - I think it is still OK though. Anyway, I give up - I simply cannot get Q103 off the board. This is really disappointing, as I've built a bazillion kits before including five QCX+, two QDX, and a QCX Mini - all with no problems. This one has me stymied.
Anyone in the group up to the task of removing Q103, placing in a new one (I have two brand new extras), and testing out / troubleshooting the unit? I'll certainly pay for your time and shipping - please let me know.
--
Jim / K7TXA
Eagle, ID
SKCC 10447C
BUG 301
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Re: QMX assembly successful but no receive or transmit
Kieth,
I am glad that you have the radio working.
For the new kits with SMD components, I have bought two tools:
1 - A hot air rework station
2 - A desoldering tool.
For the first, there are several hot air guns on Amazon.? The one I bought is no longer offered.? I would go by the customer ratings and pick one in your budget.? This one looks good.?
However I have not used it to verify it works well.? It only has 54 ratings so it could be a bad deal.? It is returnable.
For the second, there are several choices.? I started with a simple build connected to a soldering iron like this:
Which worked, but I wouldn't say I liked that it was not temperature-controlled.? Then I tried one of the spring-loaded temperature-controlled suckers and found clearing and recocking the spring was a hassle.? Ultimately, I bought a Hakko and have loved it.
If you decide to go with the bulb iron, there is a video that shows how to use it:
It's not the best video, but it does show the basics of how to use the tool.
73
Evan
AC9TU
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Re: QDX FDT86256 Mosfet PA Modification
On Wed, Sep 20, 2023 at 03:22 PM, Muhsin TA1MHS wrote:
Hi
we should be able to use?only one FDT86256 in QCX.
BS170 is 48 pF x3 = 144pF
one FDT86256 is 55pF
may be it might work better
73?
muhsin TA1MHS
Actually BS170 Ciss is 24pf. 24x3 = 72pf comparable to FDT86256¡¯s 54 pf is not too off though QCX class E PA caps still might need some tweaking. 73 Barb WB2CBA
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Re: QMX Repair - Anyone Interested?
I might be interested if I can be of service to you. Meaning I will give it my best. These are too neat of a little radio to just junk. I can appreciate your frustration!
73 Karl
On Wed, Sep 20, 2023 at 19:23, Jim Bennett / K7TXA via groups.io <w6jhb@...> wrote: You may have seen a post I did a few weeks ago regarding my QMX kit. After assembling it I discovered the dreaded short between Q103 and Q104. Power has NOT been applied. It is wired for 12 operation. I tried removing 103 but that turned into a disaster. The case came off it it and now I've got an even smaller part to try removing. I'd tried a hot air gun but partially melted the Mic connector - I think it is still OK though. Anyway, I give up - I simply cannot get Q103 off the board. This is really disappointing, as I've built a bazillion kits before including five QCX+, two QDX, and a QCX Mini - all with no problems. This one has me stymied.
Anyone in the group up to the task of removing Q103, placing in a new one (I have two brand new extras), and testing out / troubleshooting the unit? I'll certainly pay for your time and shipping - please let me know.
--
Jim / K7TXA
Eagle, ID
SKCC 10447C
BUG 301
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Re: QMX assembly successful but no receive or transmit
Oh i see now. That makes sense. The BNC probably was shorted to the sma footprint on the PC board. I only wish I had worked on the BNC connector first. Perhaps T507 was ok after all.
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QMX Repair - Anyone Interested?
You may have seen a post I did a few weeks ago regarding my QMX kit. After assembling it I discovered the dreaded short between Q103 and Q104. Power has NOT been applied. It is wired for 12 operation. I tried removing 103 but that turned into a disaster. The case came off it it and now I've got an even smaller part to try removing. I'd tried a hot air gun but partially melted the Mic connector - I think it is still OK though. Anyway, I give up - I simply cannot get Q103 off the board. This is really disappointing, as I've built a bazillion kits before including five QCX+, two QDX, and a QCX Mini - all with no problems. This one has me stymied.
Anyone in the group up to the task of removing Q103, placing in a new one (I have two brand new extras), and testing out / troubleshooting the unit? I'll certainly pay for your time and shipping - please let me know.
--
Jim / K7TXA
Eagle, ID
SKCC 10447C
BUG 301
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Re: QMX assembly successful but no receive or transmit
With just the jumper o C-C you should not have continuity from bnc
center pin to ground. On the pcb there is a footprint for an sma
connector. Make sure there is not too much solder and making a
connection.
You got this.
-mike/w1mt
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Re: QMX assembly successful but no receive or transmit
For those of you waiting to hear the end of my story ---
I first cut the wires and removed T507. I then checked the BNC connector again and found the the center pin and body were still shorted. So i used a lot of solder wick and successfully removed the BNC connector. I still could not find out where the short was but I put BNC connector back in using MUCH less solder. Then I tried to remove the wires going through the board from the now empty T507 slot. This was a disaster and it may be because the plated through holes would not permit me to unsolder the now very short wire. I thought, well this is it, the radio is done for.
Then it was suggested to jumper the C terminals where T507 used to be. I did this and the radio WORKS!
I owe a great deal of thanks for all the helpful people on this group!? I will keep watching the group and perhaps I can tweak my radio using the terminal and posting my sweep results.
MANY MANY thanks everyone!? This was the hardest build I have ever attempted and I have built a LOT of things! Tomorrow I will be scouring the manual to learn about my new radio.
My best to everyone!? 73? Keith N8CEP
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Re: QDX FDT86256 Mosfet PA Modification
Chuck,
I posted this mod as an open source free mod with the thought that anyone interested can have their pcbs manufactured or get them as a group buy. I have no intention to sell these.
First tests are promising. No compromise on 2nd and 3rd harmonics. I will perform some field tests to evaluate with realtime qsos.
73
Barb WB2CBA
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Wayne, I did get a Linux PC running FLDIGI for FSQ.? Got the Phaser retuned?to 7105 ok.? Antenna is good for 40M. I'm seeing some stuff in the 1500Hz?range but not decoding yet.? I'm sure I have to set something else up.? Not sure if I will just get decodes with out of the box setup?
I will keep working on it and when it looks like working we can try it.? Probably not tonight.
TNX! looking forward to it.??
Bob WA1EDJ
Btw, I'm setup with an NVIS on 40 meters.?
Wayne
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Re: QDX FDT86256 Mosfet PA Modification
Hi
we should be able to use?only one FDT86256 in QCX.
BS170 is 48 pF x3 = 144pF
one FDT86256 is 55pF
may be it might work better
73?
muhsin TA1MHS
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Hello All
My U3S (with QLG2 GPS module) has been working well for several months, day in and day out, 24 hours a day.
However, having had zero hits for the last 24 hours as opposed to the usual handful, I watched the unit's display and I now note that when the Tx countdown reaches the set time (02,12,22 minutes past etc.) the U3S splash screen appears and after about 5s it vanishes, revealing the usual screen which now shows the GPS time and that the next Tx time is ten minutes away.? Clearly the WSPR transmission which takes a good couple of minutes has been interrupted.? The unit recovers, does the cal run, reports the GPS data and time and gets ready to Tx then "crashes" again (reboots, you see the splash screen saying "U3S v3.12 QRP labs 2017").
The original PSU (a USB wall wart) I used still seems to provide +5V and hasn't degraded as far as I can see. The PSU has supplied my U3S which? has worked well for several months, until now.? I tried a different PSU - the USB2 output from a Hewlett Packard server which ought to be clean and also capable of 2A supply. In each case I get the rebooting problem.
At the weekend, I can get a scope onto the PSU rail to see if it is browning out and if so I can try to find a linear PSU to supply the 5V rail? and with plenty of current headroom but before I do so, can anyone confirm that this is a known phenomenon due to poor external power which has been experienced by others (rather than it being some sort of symptom of a fault with the U3S) please?
Thanks!
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Thanks, Garrett! I'm going to check that out.?
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Btw, I'm setup with an NVIS on 40 meters.?
Wayne
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Re: Vacuum-tube final for QRP transmitters?
KD8CGH - I was on that abandoned voyage as well. Alas, I'm not wise to the ways of the 'tube'
--
Dan Reynolds -- KB9JLO
<><
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I just received QMX kit so I took T30-6 and did a very quick test of the LPF. My order for the proper components did not arrive yet, so I just used some cheap 1608 ceramic chips. I only had those in E6 so I had to combine values to approximate my design... so components have errors. I just built it quick, didn't tweak anything, and I left the leads long so that I can actually use them as-is.
The filter deviated from theoretical prediction mostly in the passband ripples and the stopband ripples, but no huge major change in the overall characteristics. That's as expected.
The filter looks a bit aggressive into the 10m (I only do CW so I didn't care about slight loss beyond the CW subband) but at the same time I got pretty decent attenuation at 36MHz, so I might relax the cutoff frequency a bit upward, depending on how the actual emission looks like.
So, I think 60m to 10m implementation of QMX is one step closer.
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Re: QMX assembly successful but no receive or transmit
I will give the jumpers a try!
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Lex PH2LB
Barb WB2CBA
Karl
Dan Reynolds
Ryuji Suzuki AB1WX