Re: HELP - Broken SMD Capacitor
#qmx
. My method is to lightly tin one side of the pad, maybe very lightly tin one side of the part.? Apply heat to the tinned pad, slide the part into place, a bit more heat, align as best?as possible.? Solder the opposite side, then go back and touch up the first.? ?Curved nose tweezers help a lot.?
If it’s a little crooked or not laying perfectly flat no worries.?
Larry KB3CUF?
On Sat, Mar 9, 2024 at 12:57?AM Greg McCain via <gamccain50= [email protected]> wrote: SUCCESS !!
DigiKey came through really quick.
I experimented with BliueTak and found it good for 'picking up'? the tiny bugger and not having it fall off when moving it to the PCB? . . . but . .
my attempt to use a tiny dab of Blue Tack to hold the cap down on the board between the pads didn't really work out well. The space was so small? and heat transferred quickly when attempting to solder that the tack just softened and the bugger moved around in a blue slurry. Cleaned up everything and started over.?
Ended up just getting mentally ready, donned a magnifying head lamp I bought (cheap but surprisingly good from Harbor Freight), used a small gripper tweezer and was able to tack solder one end.
Then full soldered the other side, let everything cool and final-soldered the first end.
It looks a bit wonky but .. . . . there is good continuity between each PCB pad and the top of the metal end caps on the component.
Definitely not shorted either . . .? so one in the win column???
Greg? ?KI4NVX
P.S. Pulled another bone head mental break and ended up destroying the BNC connector. Long story ...? Complete Operator Error.
Thought I'd created a short underneath the connector housing. Brain was thinking Power Connector and there wasn't any way I was going forward if I had managed to short the main power input.
Don't have a lab grade vacuum solder removing station and the metal shell and 4 big connections to the PCB ground plane just sucked up the heat. So ended up cutting it out and then clearing up the PCB after.?
DOH . . .? not the Power IN . . .? RF IN/OUT
Just placed an order for a couple of spares.
73?
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Re: HELP - Broken SMD Capacitor
#qmx
SUCCESS !!
DigiKey came through really quick.
I experimented with BliueTak and found it good for 'picking up'? the tiny bugger and not having it fall off when moving it to the PCB? . . . but . .
my attempt to use a tiny dab of Blue Tack to hold the cap down on the board between the pads didn't really work out well. The space was so small? and heat transferred quickly when attempting to solder that the tack just softened and the bugger moved around in a blue slurry. Cleaned up everything and started over.?
Ended up just getting mentally ready, donned a magnifying head lamp I bought (cheap but surprisingly good from Harbor Freight), used a small gripper tweezer and was able to tack solder one end.
Then full soldered the other side, let everything cool and final-soldered the first end.
It looks a bit wonky but .. . . . there is good continuity between each PCB pad and the top of the metal end caps on the component.
Definitely not shorted either . . .? so one in the win column???
Greg? ?KI4NVX
P.S. Pulled another bone head mental break and ended up destroying the BNC connector. Long story ...? Complete Operator Error.
Thought I'd created a short underneath the connector housing. Brain was thinking Power Connector and there wasn't any way I was going forward if I had managed to short the main power input.
Don't have a lab grade vacuum solder removing station and the metal shell and 4 big connections to the PCB ground plane just sucked up the heat. So ended up cutting it out and then clearing up the PCB after.?
DOH . . .? not the Power IN . . .? RF IN/OUT
Just placed an order for a couple of spares.
73?
|
Re: QMX hi band birdies (internal oscillations)
#qmx
Thanks everyone! At least I now know it's not just my QMX. This is not a deal breaker for me at all - just slightly annoying because I frequently activate and chase SOTA station at around 21060-21068 KHz.
If the birdies are coming from the SMPS modules though, I doubt that firmware can solve that!
It can! The whole point of the SMPS modules in QMX is that the control loop is code in the microcontroller. The microcontroller can choose a PWM frequency whose harmonics avoid interfering with the operating frequency (generating internal birdies).?
I didn't assign high priority to this part of the work, because evidently the birdies are surprisingly un-troublesome anyway, presumably due to the double-balanced nature of the sampling detector, common mode signals including power rail noise being greatly attenuated.
73 Hans G0UPL
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Hi Eric Yes, pls send details TU 73 de Mike?
If anyone is interested in the mod's for the above server supply, please PM me and I'll get the pictures to you.?
73
Eric
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If anyone is interested in the mod's for the above server supply, please PM me and I'll get the pictures to you.?
73
Eric
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Re: Off-topic: ZM-2 tuner with QMX
On Fri, Mar 8, 2024 at 04:40 AM, Todd W2TEF wrote:
"My diople is about 33ft up, fed with about 100' of DRF-400 (with a break in the middle for a lightning arrester). It gets a perfect match on 20m (LED goes out), but only some dimming on 30m and 80m (and transmitting trips the SWR protection on the QMX). I think I got a reasonable match on 60m."
I used your assumptions above to first find the complex antenna impedance at the dipole's center feed point over average soil.? 4Nec2 results: 3.55 MHz:? ? 12-j1203 10.1 MHz:? ? 347+j882 14.05 MHz:? ?6384+j436 Next, I took those values and entered them into TLD Software to computer SWR and power loss.? TLD's menu of transmission line types doesn't include the Davis RF brand of coax so I substituted Times LMR400.? For all charts below, 100W is the generated output power.? The orange-colored oval shows how much power is delivered to and radiated by the antenna.? Moral of the story:? A 40m half-have dipole fed with 100 ft of coax, even low-loss LMR400, is a terrible multiband antenna.? However, apart from 80m, feed it with 100 ft of low-loss, balanced open feeders and magic occurs when tuned at the input end of the open transmission line.? To that point, now look at the last image below and note the? green colored oval showing the amount of power delivered to the antenna.? Paul, W9AC
80M 100W:
30M 100W:20M 100W:20M 100W with 600-Ohm Open Line:
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Re: QMX Factory Reset Defaults
Figured it out... had to use the Display to select the Version. 80-20m.? All is well... So far.? ?
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Dan and the group, I think I have isolated the issue. I had my coax strung across a cheap power strip with usb charging ports. When I moved the coax away from all the other stuff, voila, all's quiet now. I have some major organizing to do and I had forgotten I hadn't repositioned my antenna cable. Doh!!! I really appreciate everyone's help. Always start with basics one my mentors told me years ago!!! Good advice! Thanks again.
72 de WX7J Doug
Sent from my T-Mobile 5G Device
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-------- Original message -------- From: Daniel Conklin <danconklin2@...> Date: 3/8/24 2:54 PM (GMT-08:00) Subject: Re: [QRPLabs] QCX mini input noise
Please keep us updated about your progress. -- 73, Dan - W2DLC
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Re: Off-topic: ZM-2 tuner with QMX
Thanks again for responses.?
I have 10-15ft extra feedline lying on the floor where it enters the house. It's tempting to lop that off and see if a different point in the feedline matches better (similar to adding a 10' extension?) on 30m.?
From comments above, 80m isn't going to be worth trying on the current antenna. However, spring is around the corner, and my porch within easy reach of some tall trees (where the dipole is hung) is just crying out for the use of an EFHW or a tuned random wire or experiments with doublets without worrying about fixed feedlines passing into the house.?
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Please keep us updated about your progress.
--
73, Dan - W2DLC
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Re: QCX+ and SSB receiving
Yes Pierre,
JP7 and JP8 nto some (stereo) headphones.
73
Simon
VK3ELH
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QMX Factory Reset Defaults
Just finished my Low band ver 3 QDX?with 1_00_017 fw,? and had very screwy sweeps. Found a thread that mentioned a factory reset... so I did.? Now the radio thinks it is a High Band model, all defaults are cleared.? I can't seem to locate a thread or file that has the factory defaults listed.? Any pointers?
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Re: QMX hi band birdies (internal oscillations)
#qmx
Thanks everyone! At least I now know it's not just my QMX. This is not a deal breaker for me at all - just slightly annoying because I frequently activate and chase SOTA station at around 21060-21068 KHz.
If the birdies are coming from the SMPS modules though, I doubt that firmware can solve that!
Larry VE7EA.
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Re: QMX hi band birdies (internal oscillations)
#qmx
I have them also.
Eric KB1VUN
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Re: Older model QCX LCD lights up , but no display
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Re: QCX and QCX+ For Sale
Sweet!? Thank you.
Glory to God in the highest, and on earth peace, good will toward men. Luke 2:14
On Friday, March 8, 2024 at 01:43:40 PM EST, Gary K4VIG <gwgrogg@...> wrote:
Steve,
They are yours.? I'll get back to you soon.
Gary
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Re: QCX and QCX+ For Sale
Steve,
They are yours.? I'll get back to you soon.
Gary
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Re: QCX and QCX+ For Sale
I'll take them Gary.? Please call me at 727 254 0280 thanks Steve KY4GX
Glory to God in the highest, and on earth peace, good will toward men. Luke 2:14
On Friday, March 8, 2024 at 01:07:40 PM EST, Gary K4VIG <gwgrogg@...> wrote:
I have a QCX Original Rev. 3 with Rev. 1.00e version without case and a QCX+ Rev. 1? with version 1.07a? with case. Neither is working but have been working in the past.? All parts, knobs, etc. are included.? Both shipped anywhere in the USA for total of $25.00.? Call is good on QRz.com. Hope someone can use these.? My old eyes just can do the fine work as much anyone and they are excess to my needs.
73,
Gary K4VIG
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Re: QMX hi band birdies (internal oscillations)
#qmx
Hello,
Yes, there are birdies in the low band version as well, most likely from the SMPS modules. There was some discussion about it, not long ago, and Hans has in plan to implement a solution to this problem in firmware ( there's some mentioning about it In the FDIM May 2023 conference proceedings article from the QMX page, maybe in the manual too ).
The good thing is, however, that these artefacts are very narrow, and, for me at least, they're not that big of a deal while working CW. And now, with AGC, even less :-)
Regards,
YO3GFH
op. Adrian
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Re: iFTx and QMX / iPhone
Ok, I gave it a try!! It worked!!!
Following your instructions I connected the QMX through a lightning to usb camera adapter and to a usb to usb C cable. I connected a whip antenna (yes, that is a minimum footprint) and went up to the terrace in downtown Barcelona. Full of QSB.
I switched on QMX, selected DiGi mode, enable VOX and launched iFTx application. It worked!! RX was pretty amazing receiving stations from New Caledonia (!!), TX was not that amazing (but the conditions didn't allow for much more, I guess). I managed to close two contacts with Switzerland and not much more. But as a first try and with not much time, I am pretty satisfied.?
No one answered my CQ calls (ok, 2w and whip antenna) and a number of my replies to CQ calls were not answered.
I want this set up for SOTAs. Up there the conditions will be much better, and I normally use HWEF antennas. I am very excited to try the 10m band! Probably on Sunday I will give it a try.
It is true that with IFTx you don't have the options of WSJT but I think it is perfectly usable.
I will keep you posted.
Best,
Joan
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Eric K7EBR
Paul Christensen
Ray D Congdon
Todd W2TEF
Daniel Conklin
Bruce Akhurst