This is a quick scribble of the power:


These are the parts I used:

12-5 Buck
3S charger ?https://epartners.co.nz/products/jo8001
BMS https://epartners.co.nz/products/st4001-1?_pos=1&_sid=770963d6a&_ss=r
12-12 converter
Relay

It's not the most efficient way to do it, but gives the flexibility to charge from 12v or USB-C - and I had these boards all in the shack!

My battery system uses 3 x 18650 with a USB-C charge board and BMS. I'll scribble a drawing of what I've done when I get a moment.

Will do....? My plan is to use one of

I'll cut holes in the top of the box and print a grille something like this:



I'll pick up L+R feeds from the extensions to JP301 that I've extended to the dev board with headers.

Power will come from the output of my internal battery/ext 12v changeover relay.

I'll update when I have the parts and get it running!

On Sun, Jun 23, 2024 at 09:55 PM, Simone IU3QEZ wrote:

Looking at the schematic I suspect a faulty Q507 - do you guys think I'm on the correct path?

Hello Simone,

I guess yes. But there are some more parts around Q507. Could you measure please voltage at S, G and D of Q507 in RX mode.

73, Ludwig

开云体育

Hi,

While testing this midband QMX, I noticed that PA Voltage is always present, even in RX.
The QMX can happily put out almost 5 watts? in 60, 40 30 and a little less in 17 and 15, so the PA itself looks good.

Looking at the schematic I suspect a faulty Q507 - do you guys think I'm on the correct path?

73,

Simone? IU3QEZ

I've given all the joints a work over now and everything is working properly now.

The OM that taught me to solder (my Dad) would be very disappointed in those joints!

Thanks for your help

Nick

When disconnected from the main board and 7.5 volts and ground supplied at the connector on my malfunctioning 3.3V power supply, the voltages on Q111 are

drain 3.1V
source 2.38V
gate 3.71 volts



I must admit that my experience is thin in p-channel mosfets.? Do these values seem right.? I assume that I am linear mode since the LIN_REG_EN floats up to 3.7V and according to the test procedure must be pulled down to enable the switching regulator.

Thanks,
Mark

Trying to get on JS8 with my QDX and cannot seem to find a suitable radio option as one would use with FT8. Anyone know what the deal is?

Thanks in advance!
--
William, k6whp
--------------------
"Cheer up, things could get worse. So I cheered up and things got worse."

Hi John,

Thanks, that certainly clears things up a bit.? When I adjust the turns spacing -5dB seems to be about the high water mark so I'll just leave it there for now.

?

For reference, this is a QDX Rev 5 that I purchased in April of 2023 and then promptly lost in a box until about four weeks ago.? Despite the notch I'm still able to operate with it and have been having fun with FT8.? This is, however, a great excuse to get a QMX.

Cheers,
John VA7JBE

I haven't finished assembling my QMX yet but I am very happy with my Antuner AT100-M (I have the non-pro version) with my tr(u)SDX and figured I'd add it to the mentions in this thread.


I use it with the previously mentioned QRPguys SWR bridge.


73,
Cal -- AD8Q

On Sun, Jun 23, 2024 at 12:41 PM, Rowan G0KLH wrote:

May I suggest that you clean away the solder blobs on all of those pins (solder sucker or solder wick) and re flow them

Agreed, the excess solder makes it difficult to properly inspect the joint.? You only need enough solder to fill the joint, ideally the outline of the wire and the terminal should be visible.

Here is a link to a NASA spec, with great color photos of good and bad joints.
Of course we are not building spacecraft, but there is a lot of hard-won knowledge there.

73, Don N2VGU

Guys see the statistics from my recent completed QMX+


Any suggestions on how to sort out the bad Audio filters/Image Sweeps on 160 and 6 meters.? I checked the BPF's and made sure they are soldered correctly, and they are.? I used a dummy load to check the sweeps.? LPF are all spot on.

73
ZR6TM
Timo
?

Hello,
I am thinking of getting a QMX+ 160-6m multiband multimode 3-5W QRP Transceiver.? I think it would be a great radio for the beach or my own mini-field day in a park or my back porch.

I see that SSB will be (more like might be) enabled in a future firmware release.? I assume this is talking about transmit of a SSB mode?

I see this feature:
High performance embedded SDR SSB receiver with 60-70dB of unwanted sideband cancellation

So, this means I can currently receive SSB modes?? Like receiving voice modes in LSB and USB?? ?And receive modes like PSK31?? ?But no transmit.? So, the future firmware to support SSB would be for transmit?

I am OK with only receiving SSB voice modes.? But I would like to make contacts with a conversational data mode like PSK31.? But that is a wish list item.

Thank you,
Daniel KK4MRN

Thanks, Ron for the suggestions.? I thought I'd scraped enough enamel off originally; perhaps not. I put it back in its case for now and will give it another look this week.

- Bill? W3WJ

Thanks for the caution warning, Ludwig. I returned it to the 60-15 config and to its case after some more unproductive fiddling. I'll just life without 60 and 40 on the radio for now.?
- Bill W3WJ??

Adjusting the coils on the 20m low pass filter (L2 and L6) doesn't seem to have an impact on the RF sweep.? I've shuffled the coils on the BPF toroid (L12) so that the filter is only at -5dB around the indicator line (~14.1 Mhz.)? Has anyone else encountered this?

Yes, that solder could use a little touch up, but that is PWM_3V3, which is not active in the linear mode.?
I will retouch it, though.

This test was done with the power supply in isolation.? Only current limited 7.5V and ground are connected.

Mark