Re: QMX digimodes you have tested
|
3.3V L102 resistance (continuity check)
Still working on my 3.3V SMPS.? Maybe I see the real cause now.
Resistance from the + side of C106 to the cathode side of D107?
240k in one direction, 60K in the other direction.? ?The resistance reading varied quite a bit, probably because of the capacitance of C106
I also took the reading on the pads of L102.? I got similar results.? Harder to get to, so I wanted to make sure my readings were correct.
I would expect that L102 would have a much much lower resistance.? The wire does not look THAT thin.
Just noticed an identical inductor on the other power supply.? It is 2-3 ohms.
That would explain why the switcher side of this board is not working.
I have an order in for a replacement SMPS boards, but I have no idea how long that order will take.? It has not yet shipped.
Anyone know of a good source for a replacement part for this.? Digikey CD54 series only goes up to 220 uH.
Thanks,
Mark
|
Re: Help with QMX 60-15m 40M issue with receive
To Warren and Mike and anyone else who may be able to help.
I changed the bpf config for 40m from 3 to 2.? The noise level dropped substantially, but i still do not hear 40m signals.
I then took a jumper and applied it to both legs of c402.? When I did this all the noise went away and rig is dead silent except for microphonics.
I am not sure where to go.? Extremely high noise on 40m and no signals.??
I did re-update the firmware 1.0.19.? Still no luck.? I did attach a pic of the suspect area of the board as well.? Thanks for any assistance you can provide.
|
My QMX+ is working in transmit now fine with help from Jeffrey:)
However the receiver is still dead.?
Turn on my QMX+ and I get noise, and it fades out within a few seconds!
Just ordered two PCM1804's and will bring the PCB to work and install it.
???? pin 14 measures 1.49K Ohms
???? pin 22 seems low at 314 Ohms, so I willing to bet the IC is defective!
Michael N2ZDB
|
Re: QMX+ 9v Portable Power Options
This is a 6aH LiFePO4 battery with regulated 9v output.
Mine registers 9.3v until the battery is dead, lasts around 12 hours of 4.5w FT8.
|
Re: QDX Thinks is only 80M
Hi Tom,
I had this happen once. I strongly suspect a firmware bug. ?This is how I got around it:
1) install a jumper for one of the mono and bands.
2) boot up and do a factory reset?
3) shutdown and remove the jumper
4 power on the system - should be back to 6 band mode, ?if not try factory reset and restart.
i can’t explain why. ?But this worked for me.
--
73
Jeff Moore
W1NC
|
Re: Beginners Guide Request
I had order my QMX back on January 22.? The QMX changed configuration from the low bands to the mid range and then the QMX+ was introduced.? Hans has been great in accommodating me through each change.? It was exciting to watch with anticipation the weekly change in my position from 833+ down to 48 the last time I looked and then I got the email of the shipment and tracking number.? Time did go by fast, maybe not fast enough.? During that period I spent learning both CW and about the needed hardware and equipment to make this endeavor a success, especially with the great support and help from the Ham Radio community.? My thanks to everyone who has posted something on all those the topics present and in the past; a superb resource.
|
Re: Soldering Iron Question
Hans, you are not kidding! I did not have any problem with the QMX compared with the QMX+ ! I even cut off leads BEFORE soldering the caps. Will have to take another turn on the soldering iron temp tomorrow!
--
73
Karl
KI4ZUQ
|
Re: Beginners Guide Request
Andrew
I sit on the porch with a 40m efhw, every time I hook it up I check it on 20 and 40 with my nano vna. I have made dozens of pots hunting contacts with my not plus qmx.? Dive in listen, once you hear a call try it.
Everyone on SKCC and POTA has been fantastic. I was out of cw a while, and ran the SKCC sweep in January, once it got nice and my little rig came in I operate a bunch more.
Have fun
Mark N5OBC
Ps
Ordered a plus last week, 5 months to go :)
I couldn't agree more with Todd W2TEF. I checked my log and saw
we had a QMX - home brew EFHW *both ways* contact: New Jersey to
Maryland Park 2 Park on June 24th. Just pull out the keyer and
send your call. There are calls from every type and speed of key
and if we can read your call sign, then Bob's your uncle, you get
credit. 73, Sandy KB3EOF
On 7/3/24 12:35, Todd W2TEF via
wrote:
Andrew,
Welcome to the wonderful world of CW! I've just jumped back in
this year after a 20+ year hiatus.
The QMX (mine's not a +) is a fabulous CW machine.
Good job getting your voltage at 12v or less. It sounds like you
have all the pieces put together.
As long as you don't transmit (don't plug in a key), I don't think
there's any possibility whatsoever of hurting it. Listen away with
any random antenna connected.
I've been using a home-brewed EFHW for 10/17/20/40 on the vast
majority of my pota activations. I cut it to be as resonant as
possible: under 1.5:1 on most deployments. I use it without a
tuner. With each new antenna installation I do use the QMX's
built-in SWR check to verify everything is where it should be.
Occasionally this has prompted me to re-adjust how the antenna is
hung or how taut it is. Having the built-in SWR protection is
nice, though occasionally I turn it off when windy conditions give
me little transients that trip the protection.??
With nearly 1000 QSO's so far this year, the QMX is doing
terrific: no issues. It is a durable little machine with only a
little care.
Early on, I had several local friends encouraging me to step past
my anxiety and throw out some calls. I highly recommend Parks on
the Air (). It's usually very scripted, and people are out
there wanting to hear from you.?
This was an encouraging primer:
But the most fun way to get started is to find a local buddy and
do a joint activation. The encouragement and advice is invaluable.
GL es 73 de Todd W2TEF
|
Schematics for the LightAPRS-W 2.0?
Hi, are the schematics for the LightAPRS-W 2.0 available?? I'm working with some students, and we're interested in the VHF radio portion of the system in particular.? Thanks.
--James, KF6RFX
-- James W. Cutler, Professor University of Michigan Department of Aerospace Engineering 1320 Beal Avenue 3013 FXB Building Ann Arbor, MI 48109-2140 Ph: 734-615-7238 Fax: 734-763-0578
|
Re: QMX+ Power Increasing Question
Hi Greg, fine pictures except the content. The waveforms looking strange to me. Lets have a look at 1.8 MHz. The gate voltage is going down to -2V! Why negative? I guess not from the IC503. The voltage is >= 1V for around 70% of the period. The part of the waveform with voltage around 1 V is wrong. The drain voltage is low when the FET is ON. The duty cycle is around 70% for both groups. It looks like the FET are switched on by gate voltages >= 1V, so for 70% of the period. An overlapping ON is bad. For 28 MHz the FET are between ON and OFF all the time. The gate voltage stick at a medium value and couldn't go to LOW and HIGH. Something is blocking "large" voltage alterations. So I have some more questions:
- Where did you clip the probe GND to the QMX?
- How long is the ground lead from the probe to the QMX?
- Do you use the original BS170 from the kit?
- Could you show waveforms at the connection T501 - L502, at the other side of L502 and at the secondary winding of T501 for both bands?
- Could you show detailed photos from the PA and from T501 from both sides to see the windings
73, Ludwig
|
Finished buttoning my new QMX+ yesterday.?
Does anyone have a cheater sheet of commands shrunk to a double sided sheet of paper? Lots to remember hi hi.?
72/73, John WA6YSY in NW Washington state
|
Re: Beginners Guide Request
I couldn't agree more with Todd W2TEF. I checked my log and saw
we had a QMX - home brew EFHW *both ways* contact: New Jersey to
Maryland Park 2 Park on June 24th. Just pull out the keyer and
send your call. There are calls from every type and speed of key
and if we can read your call sign, then Bob's your uncle, you get
credit. 73, Sandy KB3EOF
On 7/3/24 12:35, Todd W2TEF via
groups.io wrote:
toggle quoted message
Show quoted text
Andrew,
Welcome to the wonderful world of CW! I've just jumped back in
this year after a 20+ year hiatus.
The QMX (mine's not a +) is a fabulous CW machine.
Good job getting your voltage at 12v or less. It sounds like you
have all the pieces put together.
As long as you don't transmit (don't plug in a key), I don't think
there's any possibility whatsoever of hurting it. Listen away with
any random antenna connected.
I've been using a home-brewed EFHW for 10/17/20/40 on the vast
majority of my pota activations. I cut it to be as resonant as
possible: under 1.5:1 on most deployments. I use it without a
tuner. With each new antenna installation I do use the QMX's
built-in SWR check to verify everything is where it should be.
Occasionally this has prompted me to re-adjust how the antenna is
hung or how taut it is. Having the built-in SWR protection is
nice, though occasionally I turn it off when windy conditions give
me little transients that trip the protection.??
With nearly 1000 QSO's so far this year, the QMX is doing
terrific: no issues. It is a durable little machine with only a
little care.
Early on, I had several local friends encouraging me to step past
my anxiety and throw out some calls. I highly recommend Parks on
the Air (pota.app). It's usually very scripted, and people are out
there wanting to hear from you.?
This was an encouraging primer:
But the most fun way to get started is to find a local buddy and
do a joint activation. The encouragement and advice is invaluable.
GL es 73 de Todd W2TEF
|
Re: QDX Thinks is only 80M
|
Re: QMX digimodes you have tested
CW with fldigi, using vox.
|
Re: To TCXO or not to TCXO...that is the question.
I agree with Brian. You don't need the TCXO or the AGC to operate and enjoy operating the QCXs, but it's fun to experiment and adds enjoyment to the hobby to try different variations and see the effects of them. It's all about learning new things...at least for me.
--
73, Dan - W2DLC
|
Re: Beginners Guide Request
I also acquired a RigExpert 500 stick as I was learning how to build my own EFHW resonant antennas while waiting for the QMX+.? Knowing it's probably an overkill and adding significant setup time, I will probably get into the ritual of checking all my antennas before connecting to the radio, even after using the Tenna Dipper to set the Z-match tuner when using the random wire.
|
Re: To TCXO or not to TCXO...that is the question.
I built one of the early QCXs back in 2019, and gradually upgraded it over the years, including the TCXO and AGC module. I also added PTT and CAT rig control. It's basically a QCX+ now. WSPR worked great with it before adding the TCXO. WSPR worked great after adding the TCXO. I think the standard stock QCX is more stable and frequency accurate than just about any other radio out there; it's definitely more stable than is needed for doing WSPR. But this is all about kit building, modding, experimenting, etc., and there's nothing wrong with upgrading to the TCXO. You can't go wrong either way.
Brian M
KM6ZX
|
Re: Beginners Guide Request
A great way to learn Morse Code and grow your proficient is to join and take part in SKCC activities. That's the Straight Key Century Club.?
Also, don't be too concerned about hurting your radio. You mostly see the horror stories on this group, but there are a lot of us who are just enjoying building and operating QRP Labs Radios. I've built 2 original QCXs, two QCX minis, a QDX, and a QMX and haven't blown a final yet.?
73, Dan - W2DLC
|
Re: QDX Thinks is only 80M
I've never heard of this, interesting. Did you try doing a factory reset? (vs reloading the firmware.)?
-Nate
N8BTR
|
Michael N2ZDB
William WM9H
Karl
John, WA6YSY
Daniel Conklin