Re: WSPR - Did the CME finally arrive
good morning everyone, I received a 20m reception report from Vk and W about an hour ago.? While 17 is open for Europe, at least for me.? still the propagation is closed.? 73 de iu8eun Joseph
Il gio 4 nov 2021, 14:40 Jim Sheldon < w0eb@...> ha scritto: OH Yeah, with a vengeance!? Right now (13:30 UTC) the Kp Index is over 7!? I'm just now starting to hear signals weakly on 40 meters.? 20 is still dead as a hammer as is anything above there.
Jim, W0EB
------ Original Message ------
Sent: 11/4/2021 8:26:38 AM
Subject: [QRPLabs] WSPR - Did the CME finally arrive
I am running a U3S on 40 meters and a band hopping receiver on the other HF bands and getting about 3 spots an hour.? I had thought the CME was supposed to affect this past weekend's signals.
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Re: SCRAPING AND TINNING #28 WIRE QDX
It makes sense to me. You scrape/burn off the enamel and then tin the copper wire, wiping it off quickly. ?Shouldn¡¯t be any or much thicker than the varnished wire diameter. Come to think about it I have used that technique when removing a toroid or cap in the past and then reinserting it into the same holes. Sure resoldered quicker that way too.
Dave K8WPE David J. Wilcox¡¯s iPad
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On Nov 4, 2021, at 8:59 AM, George Korper <georgekorper@...> wrote:
?Hello,
It has been suggested that the holes are too small in the PCB,
to accept tinned #28 wire. If you quickly remove excess solder with
a? paper towel so the tinning is smooth, the wire seems to fit fine.?
L14 which is a tight fit with #22 wire can also be tinned, but is a tight
fit with or without tinning.
The PCB may not be fresh, so a little alcohol rub to remove "whatever',
seems a good idea.
I didn't tin T1 and I wish I had. Didn't feel like the flow was as it should be.
Wish holes were a little bigger!
73,
George
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Re: WSPR - Did the CME finally arrive
OH Yeah, with a vengeance!? Right now (13:30 UTC) the Kp Index is over 7!? I'm just now starting to hear signals weakly on 40 meters.? 20 is still dead as a hammer as is anything above there.
Jim, W0EB
------ Original Message ------
Sent: 11/4/2021 8:26:38 AM
Subject: [QRPLabs] WSPR - Did the CME finally arrive
I am running a U3S on 40 meters and a band hopping receiver on the other HF bands and getting about 3 spots an hour.? I had thought the CME was supposed to affect this past weekend's signals.
|
WSPR - Did the CME finally arrive
I am running a U3S on 40 meters and a band hopping receiver on the other HF bands and getting about 3 spots an hour.? I had thought the CME was supposed to affect this past weekend's signals.
|
Re: QDX Surface Mount inductors
Hi all,
Thanks for your responses, I do have have a number of spectrum analysers, and I have a surface mount work station, I can remove the inductors with a hot air pencil, and fit different ones with ease. After I have built the kit with originals parts, I will measure the harmonic content, let's assume the power is 37dBm, then 60dBc would be -23dBm (25mW), I would like to see harmonic content -36dBm (250nW), or -54dBm (3.98nW), this may be a tall order?
I have HF coupler and some high pass filters and HF notches, for HF so can make the measurements. What spec are we supposed to meet?
Yaesu FTDX 10 is quoted at -50dBc for 100 Watts! on HF!
Hans, what was the original manufacture part number of the inductors you were using? I would like to look up the spec sheet.
RF design, does have a tendency to bite you!. all part of the fun
73 G8UUG
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Even if the filters are perfect, the passband is not perfectly flat. If we were using Butterworth low pass filters it would be, but most of our ham designs are Chebyshev or Cauer filters that have some passband ripple. With ideal components the ripple would be only a fraction of a dB, but it could be larger if the component values are not perfect. Optimizing the filters could be?moving the ripples around so that the desired output frequency is at one of the peaks.
Hi Wes ? Syd, adding turns to a inductor used in a LPF will NEVER result in increased output. Take a look at the response curve for a LPF, there is a knee in the curve, below which there is full output, and above which the output reduces. All that happens when you add turns is the knee frequency decreases, when you remove turns the frequency increases.?
Respectfully I disagree... What?really happens in practice is that quite often you find that increasing the inductance does increase the output power. I see this all the time. *IF* an LPF is perfectly designed and perfectly?constructed with perfect components, and with perfect 50-ohm source and load, then yes the frequency response will be a flat line until there's a knee and at that point there will be an increasing attenuation with frequency; the 3dB point is called the cut-off frequency.?
If the inductances are anything off perfect, then you can easily end up with a response which has a peak in it, and a few dB insertion loss at lower frequencies. If that peak of the response is not aligned with the operating frequency then you see low power. If the inductances are too low for the design, then increasing them to the design value can definitely increase the output power.?
What happens in QCX is even more complex because there is normally not a perfect impedance match between the PA and the LPF input. When you tweak inductance values the output power can be increased if the impedance match is improved.?
Practically speaking, when tuning up QCX LPFs I have often found that increasing the inductance of L2 improves everything. I know it is slightly counter-intuitive but this is the reality.?
Generally I think the correct approach is to see what happens to the output power when you squeeze the turns and when you spread the turns. If the power increases as you squeeze the turns, this means that increasing inductance is increasing the output power. If the maximum output power occurs when you bunched together the turns as much as you could, then the tuning range available from turns squeezing is not enough; so in that case try adding on another turn or two, then try again. Conversely if the maximum power occurs when all the turns are spread out evenly around 100% of the toroid core, then this means that the adjustment range is not enough in the other direction - and in that case try removing a turn or two, then try again.?
73 Hans G0UPL
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SCRAPING AND TINNING #28 WIRE QDX
Hello,
It has been suggested that the holes are too small in the PCB,
to accept tinned #28 wire. If you quickly remove excess solder with
a? paper towel so the tinning is smooth, the wire seems to fit fine.?
L14 which is a tight fit with #22 wire can also be tinned, but is a tight
fit with or without tinning.
The PCB may not be fresh, so a little alcohol rub to remove "whatever',
seems a good idea.
I didn't tin T1 and I wish I had. Didn't feel like the flow was as it should be.
Wish holes were a little bigger!
73,
George
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I got my QDX by TNT today. Shipping started 30th October. Within 1 Week. I hopefully will start building the QDX up next weekend.
73 de DL1SER
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Hi All,?
Back in the day when Royal Mail had the job of getting the kits to you the loss rate was about five percent if my memory serves me well. I had the job of putting the parts in the bags and taking them to the post?office. You get a much better service now, with fewer missing parts.?
Steve G0XAR (co founder of QRP Labs, now retired )?
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Re: John Palese, Jr, WB8JPH SK.
Sorry to hear it. I notified QRZ. It's my second time this week. I just cleared out a shack for a man that passed away 11 years ago. His widow never stepped foot in it since he passed. Great finds, but sobering nonetheless.
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Re: Hints for successfully building the QDX
It also says to cut the three lengths of enamelled wire to 20cm. I did this, then with the screwdriver turned it 60 times, to find it was only long enough to get seven turns, possibly eight with short tails, on the toroid. Luckily I had a?filter kit untouched so raided that to try again, making the lengths 30cm, and this time there was about 5cm sans tails over after the ten turns. It might be wise to put 25cm as the length in the manual as it's always easier to remove than to add ;)
Robbie M1ROK
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Re: Hints for successfully building the QDX
When soldering through hole leaded components i was taught to place tip of iron, pre tinned, to the pad first, wait for 3 seconds, slide iron to junction of pad and lead, apply solder then slide tip of iron up component lead and away.?
I cringe when I see soldering where both iron and solder are both applied at the same time and then both are immediately removed from joint.?
Andy?
--
The universe is made up of Protons, Neutrons, Electrons but contains only one M0RON.
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Re: Hints for successfully building the QDX
As excellent as Hans' build instructions are, I feel there is one page which could do with a bit of clarification.? That is the one dealing with winding the trifilar transformer T2.? It is absolutely critical that the start and end of the windings are identified along with the continuity checks with a multimeter. If you get a start of winding mixed up with an end, you will get no phase reversal going into the QSD inputs and it just won't work!? (Strictly speaking, this only applies to the centre-tapped secondary windings, the primary phasing is immaterial.)
I have roughly modified the pages from version 1.04 of the manual, to hopefully make this clear.? There's a couple of pictures attached...
--??
Peter Lee
G3SPL
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Re: Hints for successfully building the QDX
I reached stage 2.11 yesterday before other matters intervened, so hopefully today will be the day...
These hints may be blatantly obvious but here goes.
1.? My first step was to remove the four SMD inductors for no better reason than I could do it with the board flat on my work surface at that point.? Tweezers were helpful for two but the others came off stuck to the ball of solder on the tip of my iron
2.? If you are concerned about how much wire you need for T1, then wind L14 first and put it aside until needed.? Then you know how much you have left.? The inventory says 50cm is supplied, but the length in my kit was a generous 60cm and I had 18 cm (say 7") left at the end of my 3:3 transformer despite leaving longer tails than Hans suggests.? So you will have plenty.
3. I have several tips of differing sizes for my soldering iron, so I changed to a larger one for T1 and L14 for better heat transfer - there is room to wield a bigger tip if you are careful.? I also increased the iron temperature from my usual 350C to 390C (sorry, if you work in Fahrenheit ask Mr Google).? Seems to have worked as both passed their continuity checks first time.??
4.? If you are in the position of having to buy solder for the build, go for 0.5mm (0.02") or thinner rather than the more standard 0.7mm or thicker.? Although you can build successfully with the thicker solder, it needs more care as it's all too easy to use too much solder and create blobs and bridges.?
5.? I haven't got there yet, but if you do no other pre-switch on checks, at least check that you don't have a dead short on the DC input.? All I will say is that melting insulation has a smell of its own......
And a note for those who are concerned about such things, my QDX (order 50300) left Hans on Thursday 28th, reached his local TNT depot in Izmir around midday on Tuesday 2nd and was handed over to me in southern England midday on Wednesday 3rd.? So no complaints there.??
Good luck and enjoy the build.
Chris? G4CWS
??
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Pleased to report that my QDX is now also transmitting on 20/30 m.? Nothing beats old fashioned tracing of the circuit with an ohm meter to isolate and identify errors in eye - brain communication.? :)?? Here are readings using a Bird wattmeter with attached 50 ohm dummy load [neither calibrated by a certified lab].? Input signal is the tune function from WSJT-X Band? ? ? ? ? ? ? ? Power out [Watts]80m? ? ? ? ? ? ? ? ? ? 2.8 40m? ? ? ? ? ? ? ? ? ? 3.0 30 m? ? ? ? ? ? ? ? ? ?4.7 20m? ? ? ? ? ? ? ? ? ? 3.3 Perhaps the variation in power levels indicates a minor issue with the LPF - I have a nano-VNA and sets of good SMD caps, but I doubt if it's worth the time to investigate further.? [I checked all inductances with my L/C meter before installing the toroids.] I still find an interesting phenomena with FT-8 from WSJT-X in that I can receive/work DX stations on 20m but not local hams.? Weird.? They decode me without any difficulty... Looking into this more. Time to work on? 30m and 80 m antennas.? 73
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Hi Wes ? Syd, adding turns to a inductor used in a LPF will NEVER result in increased output. Take a look at the response curve for a LPF, there is a knee in the curve, below which there is full output, and above which the output reduces. All that happens when you add turns is the knee frequency decreases, when you remove turns the frequency increases.?
Respectfully I disagree... What?really happens in practice is that quite often you find that increasing the inductance does increase the output power. I see this all the time. *IF* an LPF is perfectly designed and perfectly?constructed with perfect components, and with perfect 50-ohm source and load, then yes the frequency response will be a flat line until there's a knee and at that point there will be an increasing attenuation with frequency; the 3dB point is called the cut-off frequency.?
If the inductances are anything off perfect, then you can easily end up with a response which has a peak in it, and a few dB insertion loss at lower frequencies. If that peak of the response is not aligned with the operating frequency then you see low power. If the inductances are too low for the design, then increasing them to the design value can definitely increase the output power.?
What happens in QCX is even more complex because there is normally not a perfect impedance match between the PA and the LPF input. When you tweak inductance values the output power can be increased if the impedance match is improved.?
Practically speaking, when tuning up QCX LPFs I have often found that increasing the inductance of L2 improves everything. I know it is slightly counter-intuitive but this is the reality.?
Generally I think the correct approach is to see what happens to the output power when you squeeze the turns and when you spread the turns. If the power increases as you squeeze the turns, this means that increasing inductance is increasing the output power. If the maximum output power occurs when you bunched together the turns as much as you could, then the tuning range available from turns squeezing is not enough; so in that case try adding on another turn or two, then try again. Conversely if the maximum power occurs when all the turns are spread out evenly around 100% of the toroid core, then this means that the adjustment range is not enough in the other direction - and in that case try removing a turn or two, then try again.?
73 Hans G0UPL
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Re: John Palese, Jr, WB8JPH SK.
You're welcome, Pat, and I'm with you on that hope, though I'm nowhere near as accomplished as he is, and I am only recently finding my opportunities as a servant of the community. John wasn't a very active participant on the forum, and I didn't know if he had other friends who would have been more appropriate conveyors of the sad news, but he was a subscriber and a QCX user, and I had advised him on a new 80m plus and was building it for him, so we were acquaintances at the very least, and I didn't want it to go unannounced.
As we get older, life feels finite and precious, and I want us all in this hobby to wring out every last QSO we can. I'm sad John didn't get to use his QCX Plus; he'd have been impressed with it.
--
Julian, N4JO.
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Re: John Palese, Jr, WB8JPH SK.
Thanks for letting us know, Julian.? Very nice of you.? I hope my obituary is as nicely done as John's.?
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Re: Classic QCX C1 fully meshed
Well yes, if you pulled it down tight - as I do - then that will make it different to thread extra turns, for sure.
Glad you're up and running. Maybe the time energized "dried out" those caps or something. I'm not a chemical engineer, so I don't know how the chemistry works, but I do know that caps are very sensitive and variable things, and that will affect tuned circuits, which depend on them having stable value.
The classic is actually very easy to connect to a QLG1, because the 4-pin header is mapped identically on both devices, by design, and you just need a piece of ribbon terminated at both ends. I think the Bama case has a removable panel for access to the GPS header...
You just have to remember to not connect the GPS when you're not in WSPR or calibrating, as it will key the Tx.
--
Julian, N4JO.
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Re: Hints for successfully building the QDX
Thanks Mike. It's really a reciprocal process: electronics may be my trade, but I'm really new into amateur radio, so I'm learning a lot from you guys who have been it for longer, in some cases, than I've even been alive. I'm just paying it back :-)
I'll finish off my QDX tonight, maybe push out some more notes, and then get back to some other commitments I'm tardy on...
--
Julian, N4JO.
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David Wilcox K8WPE
Jim Sheldon
Andrew Lenton
Shirley Dulcey KE1L
K9NUD-Steve
M0RON
Earl
Julian N4JO