Re: DK3UW QCX-Mini Multiband Schematic
I tried a search using your title and
came up with quite a lot of information, including schematics.??
I'm not sure what is exactly what you want so I suggest you try
that.
Chris, G5CTH
On 18/07/2023 19:29, Kees T wrote:
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Does someone have a link to the above design ? Maybe it was just
for the "standard" QCX+ ? Are there any other QCX-Mini Multiband
designs out there ?
73 Kees K5BCQ
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Re: DK3UW QCX-Mini Multiband Schematic
I have the QDX and QMX Transceivers (still under development) with the much higher functions but also a small "pile" of single band QCX Mini's which I would like to "multiband".
73 Kees K5BCQ?
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DK3UW QCX-Mini Multiband Schematic
Does someone have a link to the above design ? Maybe it was just for the "standard" QCX+ ? Are there any other QCX-Mini Multiband designs out there ?
73 Kees K5BCQ
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Re: Obsessive QMX tracking
Hans I much prefer your more detailed March 3, 2022 explanation:
?
I don't live next to a FedEx depot. In fact the nearest FedEx depot from me is 250km North in Turkey's 3rd city, Izmir. I get a daily collection by the local FedEx agent's friend's 2nd cousin thrice removed, then the sack(s) of packages makes its way by road North to the FedEx depot. That might take 1 day, it might take 3, nobody?knows.
?
-- 73, Rick VE7TK Website:
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Re: QCX+ R50, R48 question
Hi Glenn. What revision?is your QCX+? My older Rev 2 still used the 1/4 watt resistor at R48. It was increased to 1/2 watt somewhere in the later revisions. If your kit is older you might refer to the instructions for the revision you have. But, R48 was indeed increased in size (ie Heat Dissipation) in later revisions as it runs a little hot.
Having said that, My Rev 2 QCX+ has been running with the smaller wattage resistor for a long time and shows no discoloration to the resistor or the surrounding board area. I'm sure you are fine using it. If you have a 1/2 watt one in your junk box, it won't hurt anything to substitute it.?
73 ... Ron
I'm just finishing up my build on a QCX+ 20m.
On page 52 of the assembly manual it mentions R50, the 270 ohm resistor being "larger than the other resistors" obviously a higher wattage rating.
... but the one provided in the kit looks exactly like all the others, (1/4w?).. same with the 270ohm R48 on the front panel..
Maybe this is a leftover comment from a previous rev of the manual?
??
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Re: Software for Hobby RF Design?
On Tue, Jul 18, 2023 at 03:09 PM, Hans Summers wrote of G3RJV:
George once explained ¡°why QRP¡±, he said: ¡°Because it is a hobby we don¡¯t have to do it - or mean anything - or fit into the world plan. As long as you can do one useless thing a day - life still has some meaning and that is the essence and the joy of life¡±.
Spot on! It all gets absorbed and then one day , maybe a week or 30 years it suddenly provides an answer to a problem, or a building brick. That's why I'm forever reading decades old radio or electronics mags. ? -- - 73 de Andy -
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Re: Obsessive QMX tracking
Yes, patience is required indeed!? My latest (small) order was actioned by Hans in a day or so.? TNT then sent me an email saying "Collecting" on 10th July. It remained at the same status for precisely a week.? On 17th July the status changed to "In transit" and today (18th) it has reached Istanbul.? From past experience, once it gets on a plane to the UK, things happen pretty fast!? Here's hoping!
--
Peter Lee
G3SPL
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RR,
?I vote for a 40-15 version as well. But I would take a high band one, too. Right now I'll be very happy to see the next firmware version!
--
73, Dan? NM3A
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I'm just finishing up my build on a QCX+ 20m.
On page 52 of the assembly manual it mentions R50, the 270 ohm resistor being "larger than the other resistors" obviously a higher wattage rating.
... but the one provided in the kit looks exactly like all the others, (1/4w?).. same with the 270ohm R48 on the front panel..
Maybe this is a leftover comment from a previous rev of the manual?
??
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Re: New assembled High Bands QDX went into smoke
Seems to be a complex subject. Anyway I could fix and replace the damaged parts. Burning one BS170 always needs to replace all. And testing the output of the 74act gate also made clear that it was destroyed too. I could substitude it and the tx works again. Anyway I will install zwo zener diodes as soon as possible. I'll let you know about my experience. You can Only test the burning point of a BS170 one time ?. So the best way to decide if a protection works is the experience of other Hams. A? trx with permanent tx for 12s or even longer (wspr) normally should not transmit in full power, when it is designed for CW or Ssb. In this case I'm with you.
Diving a car you can prevent injuries by driving slowly (low power) and a seat belt (protection of the p. A) . But even if you are a safe driver, a part could fault.. ?.
72 de Natt
DL1SER
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Re: QDX 40/20/10 Variation
Thanks everyone for all of your replies.? This is some good information to mull over.? I'm curious if anyone has built a 40/20/10 variant.
Thanks all,
73,
Jon
KJ4CRW
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I'm looking forward to the 'high band' option, given where we are in the solar cycle. Having said that, developing a 'mid-band' option would be nice, in 'the fullness of time', as Sir Humphrey would say...
73 de va3rr
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On Tue, Jul 18, 2023 at 05:58 AM, Hans Summers wrote: I will have a solution available in due course.
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Re: QDX 40/20/10 Variation
Hi Jon,
I, too, had the same questions when I tried to simulate the band pass filter (BPF).? Hans' method, as he has described it, starts with a design from a simulator (Elsie) and then experiments with actual hardware to develop the best values.? Starting with the 80/60/40/30/20 meter bands would mean a small number of turns as the first coil.? The problem may be that the toroid material will not work effectively at a high frequency.? Using the following toroid info site:
It looks like the best would be the T50-6.? That would require you to adjust the turns for the 40 and 80 meter bands.
An alternative might be to modify the QMX design by taping the 20-meter coil for 10 meters and using the 0 filter selection.
The last option was reported on this server as doing away with the BPF altogether.? The results were listed as good.? This may not work in all environments, as the filter limits out-of-band signals from causing interference.??
As far as I can tell, the low-pass filters (LPF) are all close to what a filter program would specify.? You should be able to use one of the filters from the QDX manuals that matches your needs.? The BPF is used only for receiving.
All of the above are results of reading posts on the Groups.io server.? I have built all of my kits to the original designs.? I have not experimented with deviations.
73
Evan
AC9TU
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Re: Obsessive QMX tracking
Hans,
Many thanks for update and explanation of shipping process.? My order status has just changed to Shipped. Hurray!!!!? I understand that my kit is taking sightseeing tour in Turkey and should arrive with me in a week or two.?
Thanks for your wonderful radios and other kits, of which I have several. I am looking forward to building QMX and using it as my go to SOTA & POTA radio.?
---------------------------------
73 de Marek SP9TKW
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Re: Software for Hobby RF Design?
Continuing the off-topic, Fascinating.? I never came across?the Kostas SV3ORA crystal oscillator circuit?or, upon looking at it,? thought it could actually work.? From a practical standpoint, and coming from an aerospace background, it's not a very robust circuit as each crystal will no doubt have different Q and each requires an adjustable gain capability to allow oscillation by the multiple crystals simultaneously.? The output amplitude of each frequency may not be very controllable.? But still.it's pretty amazing for its simplicity.? It has always fascinated me to see how much you performance or capability you could get out of the simplest possible circuit to do the job.? An example is a single transistor L.F.? regenerative receiver or a VHF super-regenerative receiver.?
-Steve K1RF
------ Original Message ------
Date 7/18/2023 8:25:11 AM
Subject Re: [QRPLabs] Software for Hobby RF Design?
Going a bit further OT:
I wonder what you guys think of the Kostas SV3ORA crystal oscillator circuit which oscillates several crystals at the same time? He took some heat on some EE forums, where there was an opinion in some quarters that it should be impossible. Yet, it is hard to hear that something is possible when it?is happening on your bench in front of your?eyes. So I tried it here with a different JFET I had on hand and sure enough I could reliably get it to oscillate, at least on TWO crystals at the same time. For some reason I wondered if you would easily be able to simulate such a thing.?
On Tue, Jul 18, 2023 at 2:51?PM Bob Benedict, KD8CGH < rkayakr@...> wrote: I've used SimSmith to model filters and then play with component values to see how changes in value make a change in the plot in order to learn what modifications I need to fix my filters.
SimSmith has progressed to include a NEC2 antenna modeling engine and is now called SimNEC. The antenna model is just another RUSE block.
--
? 73
??? KD8CGH
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Re: Obsessive QMX tracking
Thanks, Hans! Trying to be patient!
73, Randy, KS4L
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On Jul 18, 2023, at 8:51 AM, Hans Summers <hans.summers@...> wrote:
? Hi Randy, all
A topic which comes up often.?
Our nearest FedEx depot is 250km away in the city?of Izmir. It's not like in US where you have a FedEx office in every town. So to get to FedEx they have a network of local agents, domestic courier?services which pick up daily (hopefully) from QRP Labs HQ and take the sack of boxes to the FedEx depot. It takes a few days. Sometimes 1 day, sometimes 3, who knows why. During this time there is no interface between the tracking systems of the local courier, and?FedEx tracking systems, so until the sack of packages arrives in Izmir and gets scanned, the status remains "Label created". For non-US/Canada customers, In the case of TNT (yes part of the same company as FedEx, but...) the exact same situation applies and the packages?are in the same sack(s), but the TNT status is typically "Collecting from address".?
In all cases it's nothing to worry about. You should ignore the delivery?date estimates which don't take into account the 250km gap. Once it gets to Izmir it goes fast and there are plenty of tracking updates. There are all sorts of local issues and dramas that can affect the situation too, such as the local courier, for reasons best known only to himself, not turning up to collect the sack. Or local public holidays here that you don't have in other countries. Or, we ran out of some crucial item such as labels for the FedEx printer, or bubble wrap packaging, due to a delay in incoming supplies, blah blah.?
Anyway summary message is: nothing to worry about... be patient :-)?
73 Hans G0UPL
GM Randy,
In my case the Tracking lagged arrival by about 3 days and quickly got caught up at delivery.?
It seems that ¡°shipped¡± means a label was created, after that I think that they loose it, now unlike the USPS or UPS¡. Customs does not help either.
John KK4ITX? ?Each mistake is a learning opportunity.? ? My QMX kit was marked "shipped" on July 14 and at the same time FedEx emailed me a tracking number. Checking the tracking status showed that FedEx was awaiting the package. This status has not changed as of this morning, July 18 in the US. Does this mean that my package actually has not reached FedEx. Or is this just an error in the tracking status? Anybody else see this? Sorry to be so obsessed with this!
73, Randy, KS4L
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Re: Software for Hobby RF Design?
Hi Bojan
Hans, what practical use you see in having a JFET XTAL oscillator for three frequencies when there is a very sensitive balance needed to achieve that? OK, beside the pure satisfaction when it works.?
None. The pure satisfaction that it works is enough for me. On this and on most of the rest of what I do. Practical use is a bonus side-effect.?
Besides, it is not my work, it is Kostas SV3ORA, I am just an interested follower of his work.?
Or, as our dearly beloved departed friend George Dobbs G3RJV (SK, RIP) was known to have said (I quote from? )
George once explained ¡°why
QRP¡±, he said: ¡°Because it is a
hobby we don¡¯t have to do it - or
mean anything - or fit into the
world plan. As long as you can
do one useless thing a day - life
still has some meaning and that
is the essence and the joy of
life¡±.
If you look around the other articles at? you will, if you?are like me (and George), find much of interest!
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Re: Software for Hobby RF Design?
Chris:
There are a plethora of free programs, many old. Newer and comprehensive ones are out of reach, cost wise, for the general experimenter.
A list of free programs that I use are RFSIM99, SimSmith,
Filter Design, Filter Pro Desktop(TI),RFCafe, and Tonne has at least a dozen different programs.
Most are limited in what they present, ie filter design, etc.
Few do full blown simulation, although RFSim99 and LT Sprice is good for some.
I also have a host of DOS (only) programs which are no longer worth the effort.
What I would like to convey is the following:
I might do a simulation to get a good feel for how (and if) the circuit is going to perform.
This is always followed by a discrete component build of the actual circuit.
I then measure the real circuit on the bench. If the results differ from the model, the model is wrong and must be corrected.
Then you can do variable analysis of the model for performance.
The laboratoy test on the bench is always the standard, and models have to be corrected by adding parasitic elements and other unknowns.
73 Fred WD9HNU
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Re: QDX on 20m -OR- I'm BAAAAAAck !
20 is hopping this a.m.
QDX just worked NZ2X on 14074.8 KHz? ( +/- a Hz or two )
--
72,
Bill, N4QA
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Re: QDX 40/20/10 Variation
Yes, non-standard band combos will take trial and error methods. It is not inconceivable that a particular band combo will have a similar problem to that in the QMX; that is some odd notch will give an unexpected outcome. So, playing with the BPFs will be necessary. Unlikely to be a big issue for the LPFs, but will still take some adjusting.?
--
73, Dan? NM3A
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Rick Williams - VE7TK
Ronald Taylor
va3rr
Marek SP9TKW
Randy
Fred Piering WD9HNU