I have had the big one and the mini for a couple of years and luv-em'.
Thing is, the audio on the mini is way better than its big brother. I know I can just use the mini, but I like to use them all. So, if someone can point me in the right direction to start sorting it out, I would be much obliged.
Thanks,
--
Wayne S.
KF7RCM
|
Re: How to check BS170¡¯s on QMX
Has anyone tried replacing the 3 BS170s with a single IR510? I have a uSDX using one that has been absolutely bulletproof. Maybe it is a unicorn, but it also gives 5 watts on 1Om. JS6TMW
|
Re: SOTA Batteries for QMX/QDX
Second vote for the Talentcells; I have 2 of them and rotate them. Very happy with them.
?
Greg N1TR?
|
Re: SOTA Batteries for QMX/QDX
I have this one .? Very pleased since it won't overvoltage the QMX
Talentcell Rechargeable 12V 3000mAh Lithium ion Battery Pack.?
?
|
SOTA Batteries for QMX/QDX
What's a good battery to provide 12 V to a QMX or QDX for SOTA operation? I have a battery that I use for Field Day and other ops, but it weighs something like 30 lbs, and I don't think I want to carry it up a mountain on my back. It would have to power a QMX or QDX for a few hours to make it worth the trouble.
|
I ran into a similar issue of not restarting after upgrade to _026.
It happened on a QMX and QMX+. They both stayed in USB drive mode showing both the _025 and _026 files. Could not turn either one of them on/off by pressing the Vol knob. I removed power cable and powered back on. Each of them came up on rev 26 and functioned normally.
To test, I back-rev'ed the QMX to _025 and re-installed _026 and this time it worked as normal. Dragged the file into the QMX USB drive and it copied over and it rebooted to rev 26 automatically.
--
Randy, N4OPI
|
On Sat, Aug 10, 2024 at 01:44 PM, John Laidler wrote:
I just switched off the power to the QMX, bad mistake, it now won't turn on and the LCD screen remains blank.?
John,
?
I updated as usual from a PC but the QMX wouldn't switch back on. Simple solution for me: remove the power-source, let it sit a few seconds, power on.
|
Now that we can tune in MHz, etc, I am curious if the BPFs and LPFs follow that tuning. For instance, if you are on 7.05 and you tune to 14.05. If so, when do they switch? I have not looked into it, but the LPFs could be checked easily enough with diode voltage measurement. BPF would be a bit trickier, but you could always check sensitivity on the air. Other than SWLing, I don't see a real issue for me one way or another.
Anyone looked into this?
Dan
de NM3A at mail dot com
--
73, Dan? NM3A
|
Re: How to check BS170¡¯s on QMX
Hi Mike,
?
I once used ice spray on the QDX.
It clearly shows, which transistor is drawing more power than the others during receive.
?
vy 73 Peter, DL4PJ?
|
Update:
In CW mode the housing of the QMX gets very warm with 026.
In Ft8 it doesn't.?
Both "measured" with usual rx/tx cycles.
My next step will be:
- testing rx only
- measuring the input current
?
|
Re: How to check BS170¡¯s on QMX
If there¡¯s been a problem I¡¯d remove all the BS170s and test the gate drive signals in TX before replacing the driver IC if the signals looked wrong
Re test and then all BS170s
?
otherwise you go round in circles blowing new components one by one?
|
Re: QMX+ through hole capacitors
On Sat, Aug 10, 2024 at 03:25 PM, kf7rcm@... wrote:
I ordered a couple of component kits from Amazon. Collections of caps, resistors and transistors are not expensive and are handy to have around.?
I just went through having a resistor kit with (unmarked) 10k¦¸ chip resistors in the 1k¦¸ slot.? I was working on an opamp circuit and it was a real head-scratcher figuring out why my gain was off.
Lesson learned; measure the part before installing it.
73, Don N2VGU
|
John,
Is it possible that it's still in f/w update mode?
--
73, Dan? NM3A
|
QMX+ Diagnostics Video - Feedback Welcome
I just finished building my QMX+. I'm incredibly grateful to this community for the advice and support. Thank you Hans for encouraging me to build!
?
This is my first radio build - and am relatively new to radio in general.
?
Posting a video of a runthrough of my diagnostics tests. The radio was directly connected to a dummy load and an 8.5V power supply.
?
Any feedback or thoughts on areas for improvement welcome! I'm still learning what all the diagnostics screens are telling me.
?
?
-Jon
|
Wow, great suggestion! I ran my cable six times through an FT240-31 and it instantly got better. I probably really need a new cable, but this got me back on the air. Thanks.?
?
Another symptom of my problem was that the reported frequency kept changing, drifting from 14.0740 to 14.0735 to other odd values. That seems to have stopped, too.
|
Re: How to check BS170¡¯s on QMX
I use one of the commonly available transistor testers, TC1 or similar. They are pretty cheap and will tell you if a transistor is still a transistor.
?
BS170s are so cheap though that I'd probably just replace all 4 if you've blown one... it's like $0.50 worth of silicon.
--
73
Andrew KI7FXL
|
Re: QRP Labs xciever with SSB capability
Github of usdx:
?
?
--
?
73, Barb
|
Suspect RF getting into the usb cable. Try a different usb cable, ones with a toroid choke. My qdx seems more prone as well.
toggle quoted message
Show quoted text
On Aug 10, 2024, at 3:23?PM, pgramsey, N9LFF via groups.io <pgramsey@...> wrote:
? I have an 18 month old QDX that has become increasingly erratic.
?
Running WSJT-X, it will receive fine, but as soon as it switches to transmit it errors off with the double blink of the LED.
?
The antenna is fine, SWR < 1.4.
?
I've run my QMX on the same band with the same antenna and it works.
?
It needs a power cycle to recover. Every now and then it will transmit, but the failure rate is probably something like 90%.
?
Any thoughts?
|
Re: QMX+ through hole capacitors
If you don't mind me mentioning it, I have gotten incorrect or missing components in kits. It's rare. I ordered a couple of component kits from Amazon. Collections of caps, resistors and transistors are not expensive and are handy to have around.?
--
Wayne S.
KF7RCM
|
I have an 18 month old QDX that has become increasingly erratic.
?
Running WSJT-X, it will receive fine, but as soon as it switches to transmit it errors off with the double blink of the LED.
?
The antenna is fine, SWR < 1.4.
?
I've run my QMX on the same band with the same antenna and it works.
?
It needs a power cycle to recover. Every now and then it will transmit, but the failure rate is probably something like 90%.
?
Any thoughts?
|
Bruce Akhurst
Donald S Brant Jr
Andrew KI7FXL
Barb WB2CBA