Anyone have a recommendation for someone or a website that does 3D printing at a reasonable price. I have the digital file for the object I need printed?
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73 Paul W2ECK
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Re: Removing flux. Is it necessary? Yes/No
Two tips from my experience (YMMV):
1. Warm water with a bit of dish soap and a toothbrush, followed by an isopropyl alcohol wash and a compressed-air blowoff, works well. Removing the water promptly with alcohol prevents it from causing mischief. Using both water and alcohol gets things that dissolve in either.
2. The sooner you clean the board after soldering, the easier it is to remove the flux.
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An earlier commenter mentioned alcohol attacking the green solder mask on his PCB: I've never seen this happen over many years; I would suspect a bad batch of solder mask or an unreliable PCB supplier.?
73 de N1XNX
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Re: QMX (not-plus) power issue
It seems to be constant, regardless of band. I haven't had time to do much other investigation, but I do remember that was the case.
/m
On Sun, Sep 22, 2024, at 02:41, Roy - KI0ER wrote:
I agree with Stan's assessment. When I had a blown PA transistor in my QMX, the rig (12v) was drawing over 200mA during receive.?
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I didn't have to remove the Heat-sink washer to find the bad one. It was quite obvious which one was bad, but it likely helps to remove it to see if any are warmer than others. Start with a cold radio, and don't transmit at all.?
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Stating the obvious, you have an extra 35mA going somewhere. Is that constant, or does receive current draw change by band??
?
Hopefully someone else can jump in and help you with diagnostics.?
--
73
de Roy - KI0ER
Littleton, Colorado USA
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Re: Removing flux. Is it necessary? Yes/No
Thank you community of builders!
I bought "new" soldering supplies (63/37 solder paste and No Clean flux paste both in syringes) to teach myself to solder surface mount devices-- it, and I, did well on a couple of the SMD practice boards. All the test points measured correctly and all the lights blinked as they should-- success! I did 1206, 0805, 0603, and 0402 size components all successfully. So when I started on the QMX+ I thought I'd try these "new" products-- gunky stubborn flux!?
I dug out some old rolls and found one each of; KESTER 63/37 flux 285 .020 dia. & KESTER 60/40 flux 44 .031 dia.
I think I'll proceed with the '285' and keep using cotton swabs (Q-tips!) and 91%ISA. Again I appreciate very much the community of experts and experimenters we have here together.?
'73 Robert AD6XJ
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Re: Removing flux. Is it necessary? Yes/No
BTW, I have used (and hate) no clean flux solder. ?The only thing I found that would take it off was acetone and even with that it took a while/some scrubbing.
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Re: Removing flux. Is it necessary? Yes/No
Here’s a pic of one of my boards.
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Re: Removing flux. Is it necessary? Yes/No
I’ve been using water-based flux cored solder (and same in a flux pen) for many years now. ?After assembly, I wash my boards with water, a bit of dishwashing detergent and an old toothbrush. ?Shake off vigorously and follow that up with drying using an old hair dryer. ?My boards look as good or better than machine built boards (if I do say so myself). ?I still have rosin-cored solder but doubt I’ll ever use it again.
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73,
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Robert, WA2T
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Re: qmx with tiny lcd display
Thank you for this information Barb! I also have been looking for a smaller display.
I have not made the QMX but see that it has a HD44780-compatible LCD display. I built the DDS Synth VFO and it works very well. I want to build it into my TXVR for backpacking and hiking. The problem is that the LCD display is too big for my need (and I dont need two character lines just the freq) and so make the panel larger. So this should save some space!
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Maybe on the ground to the radio? Do you use an external tuner? If so then you can ground there.
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Fortunately USB-C cables are made for high-speed connectivity so they have better braid-shielding over the center conductors; Many of the older USB-A cables had miserable shielding and I had to do through a process to find good ones for my SDR Play Duo to minimize RFI. You can also get a couple of clip-on ferrites and wrap as many turns of the USB cable through the ferrite... The more turns through the ferrite the greater the attenuation will be.
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Not grounding at the tuner could result in some 'weird' effects where the SWR looks good leaving the radio to the tuner, but the radio and laptop are also acting like part of the antenna system.
--
Tisha, AA4HA
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Re: Removing flux. Is it necessary? Yes/No
Some days ago someone posted a Google link to Kester’s no clean solder. Reading that document I learned that their flux was unaffected by IPA, even 99%.
So I agree with others that good old rosin core 63/37 is easiest to solder with, and cleans up nicely with IPA. The 70% works well.
Just don’t eat lunch at the work bench, wash your hands before eating, and clean up the solder splashes on the bench and floor.
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Show quoted text
On Sep 23, 2024, at 08:02, Donald S Brant Jr via groups.io <dsbrantjr@...> wrote:
? On Sun, Sep 22, 2024 at 09:34 PM, Robert AD6XJ wrote:
So I am still looking for a solution (pardon the pun) to get rid of this flux.
Fix the problem at the source, get rid of that no-clean fluxed solder and get a roll of 63/37 with RMA flux from Kester or Multicore and clean it off with ordinary isopropanol and a cut-down acid brush..
Life is too short to deal with annoying stuff like crappy solder intended for commercial use.?
Don't get me started on lead-free solder.....
73, Don N2VGU
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Re: 180pf (181) Capacitor Needed
Dear Tisha,
I have some of those capacitors and I can mail them to you FREE.
Just need to know if your address is good on QRZ.com
Take care and have fun
73 Dave WA5DJJ
SUPER GRABBER -
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QDX image freq, someone else who would look at it?
although I think I'm an experienced builder it may be that I'm
missing something. Having gone through all the checks and replaced or
re-did components as recommended I still have no image frequency
suppression. Having only a two channel scope, and from what I think
I'm seeing all looks well, I've come to an end of troubleshooting. If
the problem is not resolved the QDX will be shelved until I need a WSPR
beacon transmitter.
Who would I be able to send it to for an evaluation or
troubleshooting?
I'm in Canada.
Ron VE8RT VE8TEA
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Ron VE8RT <ve8rt@...>
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Re: Removing flux. Is it necessary? Yes/No
Robert,
For board cleaning I am using Isopropyl alcohol brushing the board with a tooth brush.
The solder I use is Kester no clean 63/37 and the flux can be easily removed.
No harm done to the board either.
I tried cotton swabs before and they don't work, like you discovered yourself!
73,
Roelof, pa0rdt
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Re: Still no output on QMX
On Mon, Sep 23, 2024 at 12:05 AM, Paul - AI7JR wrote:
Don't know what the comparative losses will be in a switching regulator... Close maybe, but I don't know which would be better!
A switcher at 95% efficiency would waste 12W x 0.05=0.6W vs 1.8W with diodes.? So 1/3 the loss.
73, Don N2VGU
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Re: Removing flux. Is it necessary? Yes/No
On Sun, Sep 22, 2024 at 09:34 PM, Robert AD6XJ wrote:
So I am still looking for a solution (pardon the pun) to get rid of this flux.
Fix the problem at the source, get rid of that no-clean fluxed solder and get a roll of 63/37 with RMA flux from Kester or Multicore and clean it off with ordinary isopropanol and a cut-down acid brush..
Life is too short to deal with annoying stuff like crappy solder intended for commercial use.?
Don't get me started on lead-free solder.....
73, Don N2VGU
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QMX+flickering black line on display
Hello
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since a few days I have a QMX+.
All is fine and I love this addition to my QMX(80-20).
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From time to time I am notice a black line moving from left to right beyond the frequency display.
Morse decoder RX and TX is off.
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Even in TX-Mode and semi QSK auto on.
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73 de Harry, DK2GZ
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Re: qmx with tiny lcd display
Hello Yoon,
yes you are correct with your assumption.Its planed a HT like the KH1 with battery, speaker and perhabs automatic tuner inside. On the other side,since the last weeks, i'm trying a manually tunable telescopic whip with ferrite core.
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And if you have a 1:1 SWR match to your vertical, what are you using the tuner for??
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With the setup I described, I use 20 feet of coax, so that's my approx distance from me to the antenna.?
--
73
de Roy - KI0ER
Littleton, Colorado USA
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I had run into a similar situation. And this solved it:
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Amazon.com: Digirig Shielded Short USB-A to USB-C Cable with Ferrites : Electronics
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I so use this:
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RF into the computer is gone.?
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For a vertical, a ground connection is only for lightning or static charge protection. It won't do much for rf. So without a proper counterpoise, there's going to be rf issues.?
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I use 2 raised tuned radials on my 1/4 wave vertical in the field, and the common mode choke is a nessesity for this set up.?
--
73
de Roy - KI0ER
Littleton, Colorado USA
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Re: Still no output on QMX
If you use a linear regulator, then you're correct-- It generates
heat and will "waste" power...
The buck/boost regulators are all switchers, which will
(nominally) waste less power. Consider, if you use 3
silicon diodes to bring 13.8 volts down to (roughly) 12, and draw
1 amp on transmit, that will be about 1.8 watts dissipated in the
diodes--and that loss won't change as the battery voltage drops.
Don't know what the comparative losses will be in a switching
regulator... Close maybe, but I don't know which would be better!
73, Paul -- AI7JR
On 9/22/24 02:03, James via groups.io
wrote:
Hi Paul, I initially built the 9V version of the QMX.?All my
power sources are either 13.8V or 12.8V. My thoughts were
building the 9V version with a voltage regulator inline of a
dedicated power cord. ?My
only concern, and honestly I'm not knowledgeable to know, but
I was thinking that the extra voltage would be dissipated in
heat, and the hotter the regulator would get, the more
amperage it would draw. I was going to inquire about this
theory, but then actually getting any output at all out of the
rig became the major concern. In the middle of all that, I
rebuilt it to the 12V arrangement. Right now I'm not sure why
I'm not getting any output so like I said, I will reassemble
the rig and run the test that Ludwig was suggesting and go
from there. Thank you for your input. After I tackle the
output problem, I'll check into your suggestion. I'll try to
find some information on which is better, boosting up to 9V,
or regulating down from 12V.?
?
James
KA9TII??
--
Paul -- AI7JR
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Steve H
Tisha Hayes, AA4HA
Donald S Brant Jr
Paul - AI7JR