Re: QMX build for [40m/30m] , [20m/17m] & [15m/12m/10m]
#qmx
On 13/08/2023 09:17, Nick G4IKZ via groups.io wrote: I accept that this will require total redesign of the filters. For simulation I intend to use QUCS Nick, Note that others have not been able to successfully simulate this sort of filter. There are significant stray capacitances to make it difficult. One design had an unwanted resonance that ruined 20m. Be prepared for trial and error, fitting BPFs when you know it is working. 73 Alan G4ZFQ
|
Re: QMX Congenital problem with Q103/Q104 Board short spelled the end....
Were you able to do the multimeter ohm check to see if the drain to drain short was present? I can't recall where I saw it discussed but that short between drains was initially fairly common, it seems. I think Hans shifted component location a few thousandths away in subsequent productions....
Meanwhile, some old stock may be sifting through.
Hey! I used the wrong assembly revision and built a totally deaf QMX!
73
Karl
KI4ZUQ
|
Re: ultimate S3 .. how to solder on an antenna
Hi John,
Sorry for the late reply.
(Summertime .. :-) )
Thanks for the photo's. In the mean time, some other hams gave me
the same advice as you: just use a small "intermediate" wire.
Apparently, I had an assumption on impedance matching that is much
more strict then what is needed in reality.
The secure-cable connection (2nd link) also looks interesting.
I'll look into it too.
Thanks!
73
kristoff (on1arf)
Op 10.08.23 om 10:58 schreef John
Kirby:
toggle quoted message
Show quoted text
?
My U3S-s?
""Any hints would be welcome :-)"...Kristoff (on1arf)"
Hi Kristoff,
My image is by no means the 'recommended' or correct impedance
matching technique but works very well at QRPp levels
AND orders of magnitude easier than dealing with short runs of
coax? :o)
AND especially helpful for an LO set apx 0 dbm then attenuated 6dB
for that TT 1056 receiver
The current 'tool-up' is for the 2023 es 2024 eclips hamSCI.com
Grape Project? see my QRZ.com page for more info
A side project that WSPR beacon is set apx 100mW into that dummy
load THEN (for now) the ant (132ft inv-L / 1:4 UNUN / Earth
counterpoise) is switched by hand but with Hans filter/relay kit
under construction
Again only a quick es dirty way of not dealing with coax es/or
coax connectors :>)
72 73
John
N3AAZ
FM19? on? DELMARVA Peninsula
|
QMX Congenital problem with Q103/Q104 Board short spelled the end....
QMX Smoked upon completion...found the thread about the Q103/Q104 short and 1N4148 popping.? Got the diode replaced,
but moving Q103 proved impossible. Regulator board is beyond repair now. If nothing else was damaged by the board defect,
the another regulator board without the short gives a good chance of the radio coming alive.? I'll contact QRP Labs. Bob -AB5N
|
Re: QDX suddenly died, blown fuse, burning smell.
Almost forgot...
The MCU also draws 5V power through its 3.3V linear regulator. Let's
hope the fault is not at the MCU!
JZ
toggle quoted message
Show quoted text
On Sun, Aug 13, 2023 at 7:34?AM John Zbrozek <jdzbrozek@...> wrote:
Mark,
If a failure at the output transistors caused IC5 to fail as well, a hard short on the 5V rail is possible. I would check there first.
Beyond that, the entire receiver chain is a customer for 5V power, from the band switching mux chips and Tayloe detector, tha op amps, and the analog front end of the ADC. Isolating the short, if it is in that chain, is a good bit more challenging.
Looking for temperature rise on each of the involved chips may be a way to locate the short.
JZ KJ4A
On Sun, Aug 13, 2023, 7:13 AM Mark Palmer <esperanto2023@...> wrote:
Very briefly, my QDX which was working perfectly seems to have died suddenly. Working fine, but after a fairly long FT8 session, suddenly died with pop from inside and nasty burning smell.
Initial checks with multimeter show a virtual dead short on the output pin of the main 5v voltage regulator. I've visually inspected for signs of burning, but no joy.
Can anyone give me any pointers of where to start looking? Would blown transistors in the PA give a short that severe?
Any advice welcome!
Mark G0OIW
|
Re: QDX suddenly died, blown fuse, burning smell.
My high band has blown during 20m ft8. 2 of the 4 bs170 where cracked, that took the driver ic5 out witch drove the 12 volt direct on 5 volt power line taking out some more components and now even the 3,3 volt components are shorted.? Even the processor gets very hot when I apply 3,3 volt directly to the 3,3 volt power line.?
It pulls over 800ma..?
So its total loss, I guess.
Root cause was 14,1 volt in stead of 12 volt.. and yes I know now. That's really to mutch.?
But you may be lucky.
At least you used a fuse witch is the real missing part in this great project..
Very briefly, my QDX which was working perfectly seems to have died suddenly. Working fine, but after a fairly long FT8 session, suddenly died with pop from inside and nasty burning smell.
Initial checks with multimeter show a virtual dead short on the output pin of the main 5v voltage regulator. I've visually inspected for signs of burning, but no joy.
Can anyone give me any pointers of where to start looking? Would blown transistors in the PA give a short that severe?
Any advice welcome!
Mark G0OIW
|
Re: QDX suddenly died, blown fuse, burning smell.
Mark,
If a failure at the output transistors caused IC5 to fail as well, a hard short on the 5V rail is possible. I would check there first.
?Beyond that, the entire receiver chain is a customer for 5V power, from the band switching mux chips and Tayloe detector, tha op amps, and the analog front end of the ADC. Isolating the short, if it is in that chain, is a good bit more challenging. Looking for temperature rise on each of the involved chips may be a way to locate the short.
JZ KJ4A?
Very briefly, my QDX which was working perfectly seems to have died suddenly. Working fine, but after a fairly long FT8 session, suddenly died with pop from inside and nasty burning smell.
Initial checks with multimeter show a virtual dead short on the output pin of the main 5v voltage regulator. I've visually inspected for signs of burning, but no joy.
Can anyone give me any pointers of where to start looking? Would blown transistors in the PA give a short that severe?
Any advice welcome!
Mark G0OIW
|
QDX suddenly died, blown fuse, burning smell.
Very briefly, my QDX which was working perfectly seems to have died suddenly. Working fine, but after a fairly long FT8 session, suddenly died with pop from inside and nasty burning smell.
Initial checks with multimeter show a virtual dead short on the output pin of the main 5v voltage regulator. I've visually inspected for signs of burning, but no joy.
Can anyone give me any pointers of where to start looking? Would blown transistors in the PA give a short that severe?
Any advice welcome!
Mark G0OIW
|
One cold/non-conducting solder joint in the header connector....
73
Karl
KI4ZUQ
|
Re: QMX build for [40m/30m] , [20m/17m] & [15m/12m/10m]
#qmx
Hi Nick
Up to 6 bands are user configurable. There's nothing to stop you defining a band named 1012 with a frequency range 24MHz to 30MHz. It would have to refer to the same BPF and LPF that's all. Remember you have 4 BPF taps and 3 LPF taps. In my opinion 7 amateur bands is probably stretching it and will be challenging!?
The TX PA and Receiver are fundamentally the same or similar to QDX. I measured good receive sensitivity on QDX even up to the 8m band (40MHz). TX power drops off slightly with frequency but I usually get at least 4W on 10m. 73 Hans G0UPL
I just joined the group after ordering a QMX kit. If possible I’d like to build it from the outset for the band groups stated above. I accept that this will require total redesign of the filters. For simulation I intend to use QUCS which is now available via Ubuntu Software. And I have a NanoVNA to help with the practical work.
?
But before thinking too hard about filter design I’d like to know more about the likely performance of the remaining hardware at higher frequencies. Particularly the Tx output power and Rx noise figure (especially as there is no LNA). To look in to this these things I was thinking that I might first link out the filters with a direct coax connection???and thus measure the raw Tx power and Rx NF available at the BNC before filter losses. And then I wondered if anyone else had already done that?
?
Another issue is that my intended radio would be for seven bands. Does anyone know if the firmware can accommodate seven bands, and whether or not the user can determine what the bands will be without having to get modified firmware?
- Nick, G4IKZ
|
QMX build for [40m/30m] , [20m/17m] & [15m/12m/10m]
#qmx
I just joined the group after ordering a QMX kit. If possible I’d like to build it from the outset for the band groups stated above. I accept that this will require total redesign of the filters. For simulation I intend to use QUCS which is now available via Ubuntu Software. And I have a NanoVNA to help with the practical work.
?
But before thinking too hard about filter design I’d like to know more about the likely performance of the remaining hardware at higher frequencies. Particularly the Tx output power and Rx noise figure (especially as there is no LNA). To look in to this these things I was thinking that I might first link out the filters with a direct coax connection???and thus measure the raw Tx power and Rx NF available at the BNC before filter losses. And then I wondered if anyone else had already done that?
?
Another issue is that my intended radio would be for seven bands. Does anyone know if the firmware can accommodate seven bands, and whether or not the user can determine what the bands will be without having to get modified firmware?
- Nick, G4IKZ
|
Re: ultimate S3 .. how to solder on an antenna
?Hi Kristoff, et al,
re... coax antenna connection
Take? lQQk at this
https://qrp-labs.com/ultimate3/u3mods.html#ant
COAX but no connector to fiddle with
72
John
N3AAZ
|
Hi Dennis
Ok yes, I suppose D101 doesn't necessarily blow every time. The 1N4148 absolute maximums specify 2A for 1us, 150mA avg current, 0.5W dissipation... If the abuse was short enough and/or you were using a current limited supply and/or with a bit of luck... It could stay alive. 73 Hans G0UPL
On Sun, Aug 13, 2023, 12:44 AM Dennis Rieger < kk5db@...> wrote: Hans,
Unless I am missing something the diode D101 has not failed even though I had a short between the two drains. I powered it up after I moved Q103 and it has been working just fine.
Dennis
KK5DB
|
Re: FT8CN English manual translation
I have also used deepL to translate legal documents from French into English. A little post-editing is sometimes needed but the results are more intelligible than the original.
John F5VLF
toggle quoted message
Show quoted text
On 10 Aug 2023, at 07:48, Timothy Fidler < engstr@...> wrote:
Don't use Google translate; Use? ?DEEPL? from Germany as available online . Deutscher Qualitat versus? US high tech half As$ equivalent. US is very good at slick stuff that in fact is pretty flaky . After Apollo,? things in the US kind of went to hell in a Hbasket except in very specific areas where if you? messed up you went to Gaol for a hundred years and lost ya shirt too..... Back to Deep L?
Deep L puts in synonyms where? there is? a repetition? of a given word - that's pretty slick. It also handles bulleted lists natively . It handles about? 2.5 x as much text per Tx? in the on line version.
Nope my brother does not own the company.?
Bleat from me -? If anyone works out how to download and get running on a? Win 7 OS I am all ears for an idiot guide.??
I used DeepL? to do the translation E to? French of the? Qcx Mini manual . For nix? , Cause I love? Hans so much.? ? It was interesting exercise.? It's amazing how much work is required to do it as a clean job. You have to do the rough cut with DeepL and then do a clean up by hand .? For instance what do you do when there is Embedded? Anglit text in a??Photograph ??? ?- in my case ... not a lot - but I added more description underneath.?
That's a hint for anyone writing a tech manual that may need translation.? Embedded text might look sexy but it's not conducive to a clean translation.?
French specific notes -?
French tends to be more terse than English so you have fun trying to keep the pagination the same.? I decided to leave all the Front TOC in English so that upgrades on future versions of the manual would be easier to track.? Working smarter not harder.. something like that.? I'll stop before I put my foot in it. Vive La France.? Vive Madelaine.? ?
|
FDIM 2023 Hans Summers G0UPL "Evolution in Radio Design: building the next"
|
Hello Everybody
I recently finished the assembly of a vanilla 40M QCX-mini kit... ** I put power to it (9v from wall wart) and.... Boom, works as expected. Yay, me! I took a leisurely?week, a couple hours at a time, to put it all together.? Amazingly well-curated instructions!??
Thoughts?/ observations:
I couldn't budge the peak of the BPF until I removed the anti-static bag I had placed underneath the radio's PCB.? Doh!??
I have the QRP labs dummy load and with the 9.33V wall wart supply, I measure 12.03V at the RF detector.? Using the handy graph ("Guide to RF Power Measurement" ), and adding a nominal voltage drop from the diode, I guesstimate 2.5W out.? Any thoughts on relative increase in voltage/Watts out, if supply is bumped to 14V???
Additionally, I carefully?wound?the inductors as evenly as possible, and spread the windings out to fill the entire toroid, with no large gaps. I watched the video about?tuning the CQX and my initial power measurement (with stated caveats) seems pretty encouraging.? I'm curious as to potential gains if I monkey with the windings on the inductors.? The aforementioned video was pretty specific to a 20M build.??
I really like the idea of the built-in power meter (understanding its limitations), but I find the instructions in the "Guide to RF Power..." a bit confusing.? It mentions a 3-pin header, but it seems to be a 4-pin header on the board and schematic.? I'm a little nervous about roaching my radio with a ham-fisted mistake.? I want make sure I know what I'm doing, and the fantastic quality of the instructions makes me doubt myself.? I think I need to connect a jumper from the RF pin to the center conductor at the BNC connection. It makes sense to me that this jumper would naturally go under the main PCB.?
**? I have since ordered the AGC and TCXO modules after appreciating their value and functions.? Easy upgrades to make!
I have dreamed of building a QRP CW rig for years, and huge thanks to Hans for all his excellent work and support.??
73 Todd KE7AJZ --
?? ? ? ? ? _ ? ? _ ? ? ? ? ? ? ? ?
?___ ?___| |__ | | ___ _ __ ___ ?
/ __|/ __| '_ \| |/ _ \ '_ ` _ \?
\__ \ (__| | | | | ?__/ | | | | |
|___/\___|_| |_|_|\___|_| |_| |_|
twitter @theschlem? ? ??IG? @the_schlem? ? ? ?KE7AJZ
|
Well, I have built a QMX after successfully building a QCX plus and a QDX. Got through the smoke test, and loaded the latest firmware. After uploading the firmware, the LCD came on and now the unit displays the splash screen with no responses to any inputs. Any ideas??
|
The RX curent seems too low to me. I have no idea what is the unit to unit variation but mine takes 98mA at 9V with the backlight on. Without the backlight it drops by about 9mA if I recall correctly.
|
Re: Reviving/Revisiting Damaged QDX - Troubleshooting advice needed
Charles,
I think that clock generator needs to be replaced.?
JZ KJ4A
On Sat, Aug 12, 2023, 10:04 PM Charles Johnson < cjohnson@...> wrote: To all,
My apologies for the large type in my previous post. I wrote it in the Notes app on my iPad and when I copied and pasted it, despite my best efforts, I couldn't make it smaller :-/
Regards,
Charles Johnson
KF4AYT
|
Re: QMX Poor contrast with backlight on
Yes, I have the trim pot turned full left (counter-clockwise). That's the only position that gives legible contrast.
And it looks like I was premature in saying the problem has worked itself out. After starting up from being turned off several hours, the backlight is back to giving crappy display contrast. It looks like if I turn the backlight on while the QMX is transmitting, the screen can flip back to having good backlit contrast.
|
Karl
Bob Nagy AB5N
Mark Palmer
Todd Schlemmer