Re: QMX+ T507 winding direction?
It won’t make any difference. I tested one wound in the same sense and again in the opposite sense and no difference. These are two independent windings. As long as you put the wires in the circuit board hole on the same side of the core where the wire exits, it will work. If you cross the wire under the core and connect to the board hole near the other end of the core you will have problems.?
Ron
In the QMX+ does the polarity of the 10-turn windings on T507 (part of the Fwd/Ref power detector) matter? In the assembly manual the photo looks like they're wound to be mirror images of each other. I wound mine so the turns advance clockwise on both sides.
?
Will this cause a problem with RF power measurement? Or worse yet, cause a serious impedance mismatch for the lowpass filters and finals?
?
|
Re: Does the QMX need a mic preamp? #qmx #QMXplus #SSB Firmware beta 1_01_003 release
#qmx
#QMXplus
#ssb
I also struggle with background noise that is present in my modulation. I have tried all the options and the only thing that is certain is that the noise is reduced by reducing the gain. The noise gate helps a lot in removing noise in moments of silence, but it contributes to distortion at the beginning and end of words, especially if it is set high. It seems to me that this background noise is currently the weakest point of SSB on the QMX.
Maybe not everyone has this problem to the same extent. I have two QMXs and with the same microphone and the same settings I have different levels of noise.
?
73, Zrinko Ivan, 9A7AM
|
Hello Reiner,
?
Thanks for your comments.
This is an interesting issue to play with!
?
73,
Roelof, pa0rdt
?
?
|
After playing with CW filters, I have a few comments...
?
When a single (not cascaded/compounded) 300 Hz or 500 Hz filter is selected, the ultimate rejection is not great. I can still hear a moderately strong station, 2 kHz away.? However, selecting a 400 Hz filter, which internally cascades 300 Hz and 500 Hz filters, results in excellent ultimate rejection.
I can't see any reason not to cascade two copies of the SAME filter, for example if you have 700 Hz center, 300 Hz bandwidth, I could cascade two such identical filters together, which would improve the ultimate rejection without altering the passband.? ? It would be nice to be able to select a lower center frequency. Personally, I prefer 400 Hz.
Also on my list...?
73 Hans G0UPL
|
Try sending the stored message to a dummy load and see if you can replicate the issue.
|
Hear here!? Absolutely.? This group is one of the best I've ever found for people helping each other.? My home built QMX worked fine from the first power-up, but I visit everyday to learn more about Han's great products. Even with a running radio, there is a lot to learn here about various settings: filters, AGC, test sweeps, etc.
?
Many thanks to all who help!
?
Off to smoke test a QMX+.
--
72 de N4REE, Bob Easton - QRP CW forever
|
Re: SWR and PWR does not show lcd
Solved, T507 is not properly soldered.
Thanks to everyone for their patience and especially to Hans for his work
|
Well expletive deleted.? Thought I was on to something.
?
I looked at and touched up a couple of solder joints on the Q5xx transistors with no change in symptoms.
?
Going to try looking at it again later today.
?
I'll update you if I find anything or give completely up.
?
Thanks.
?
Andy
WB9YXA?
|
Does the QMX need a mic preamp? #qmx #QMXplus #SSB Firmware beta 1_01_003 release
#qmx
#QMXplus
#ssb
Hi All,
?
Just wanted share my experience with you.
?
I have experimented with 3 electret mic capsules so far. 2 that I scrounged off of other boards and one utilising the mic from my PC gaming headset.
?
The mic from the head set resulted in low volume and unsatisfactory modulation. When I turned up the mic gain on the QMX+, the QMX also amplified internal noise creating unacceptable background noise in the modulated output.
?
The other two capsules were a little better but still unsatisfactory.
?
One of the capsules that I had took off was from a MAX9814 Arduino mic amplifier module.?? I thought, "Hey, why not use the amplifier module to use with my headset!"
?
Well, I did just that. I wired up 2 x 1.5v AA's in series to power the board with and wired the mic from the headset as the input to the amp. I then wired the output of the amp to the mic input of the QMX via a 1uF capacitor to block the 3.3v dc from the QMX.
?
Well, that done the trick! I'm getting much better results now. But I did have to reduce the mic amp module gain as it was way too high.
?
As it currently stands, I am unable to achieve a satisfactory calibration with any of the bands on my QMX+.? As a result of this, my QMX+ is in default calibration settings.
?
The mic gain on my QMX+ is now set at 35 and have made a few contacts with good reports with this setup.
?
Now, the question is, how do I wire up the mic amp module to the QMX using the 3.3v supply on the TRS rather that using batteries?
?
I? did try taking the 3.3v via 2k ohm resistor from the QMX TRS terminal to the vdd of the mic amp module, and connect the output of the module back to the same TRS terminal via a 1uf dc blocking capacitor, but sadly that didn't work. I'm clearly missing something...
?
?
Cheers,
?
Mel. M0KMD.
?
?
?
|
FT8TW (Android) - a FT8CN fork - QDX/QMX and pskreporter working.
|
Re: SWR and PWR does not show lcd
So this means?it's a hardware fault not a firmware fault. I'd suggest checking the connections of T507.?
That's the problem, it doesn't read the power.
Do I need to check the T507?
Thanks Hans
?
|
Re: SWR and PWR does not show lcd
That's the problem, it doesn't read the power.
Do I need to check the T507?
Thanks Hans
?
|
Re: SWR and PWR does not show lcd
When you key the transmitter in the Hardware Diagnostics screen (and my apologies if this has been mentioned already) does it read the correct (approximately) power?
The default values.... update interval=50 and? "tx->RX hang time=50.
?
|
I also use 2x3 BS170s on my 9V QMX+.
The power increases by almost 1W, and the heat on the BS170s decreases slightly.
However, the larger capacity of the 3x BS170s affects the LPF tuning, especially on my 20-17-15m LPF and higher too.
I had a lot to tuning.
?
73 Reiner
|
Re: SWR and PWR does not show lcd
The default values.... update interval=50 and? "tx->RX hang time=50.
?
|
Hi Andy
I don't think that is the cause; the chipped ferrite is very common and doesn't normally cause functional issues.?
I believe I found it.? L501 is missing a corner and coils are exposed.? I was so focused on solder joints I didn't see it until I got an oscilloscope involved and I was tracing the pwm signal.
?
I actually have a replacement on hand, I'm going to try to swap it in for the damaged part.
?
Thanks all for your positive comments.?
?
73
Andy
WB9YXA?
|
A new chat has been created:
Is it possible while my order is not shipped (assembled QMX+): to order dummy load and no to pay for delivering it with QMX+ together?
By:
Algis Unknown <wiseacre1@...>
View/Join This Chat
Do not reply to this message to post to the chat. You can participate in chats only through the group's website.
|
I believe I found it.? L501 is missing a corner and coils are exposed.? I was so focused on solder joints I didn't see it until I got an oscilloscope involved and I was tracing the pwm signal.
?
I actually have a replacement on hand, I'm going to try to swap it in for the damaged part.
?
Thanks all for your positive comments.?
?
73
Andy
WB9YXA?
|
Re: SWR and PWR does not show lcd
Bottom line right of digi sign is swr, since it is? coars and your 1.2 swr is low enough probably it does not show enough to fill the part of square. You can attach a 80-90ohm resistor on output and do the test.
Or simply remove antenna transmit in tune mode if swr protection kicks in then hardware is fine.?
|
|
|
Ronald Taylor
N4REE - Bob
dl8lrz Reiner
Ivica - YU1QRP