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Hi Colin,

3 volts is high.? It should be 2.5 volts or slightly lower.? The best measure is to see the waveforms on an oscilloscope.??

2 ways forward:
1 - assume IC5 is bad and repalce
2 - remove the 4 BS170s and test the gate pad levels again.

I suggest replacing IC5 as the potentially least amount of rework.? In future repairs, always check the gate drives with the BS170s removed before installation.

73
Evan
AC9TU

Hi
I recently found my qdx which was putting out a healthy 5w on all bands had dropped to 3w on all bands. I found one of the BS170s faulty and replace all four. Still only 3 w. I am looking at the gates of the pa and seeing? about 3v peak to peak on all gates. Is this the correct level or should it be more. I really do not want to replace ic5 if not necessary.? Hope someone can help 73s G8LDJ

Steve, maybe the fold from step 1 is a little bit (to) long. But ...
"Step 3:
Cut another 20cm (approx) of wire and lay it equidistant across the holes as shown:" (underlined by me)

I have 7 cm sticking out of each side of the binocular core

This means after step 13 you will have around 2.5 ... 3 cm twisted wires sticking out of each hole. This should be enough.

73, Ludwig

I find cat works with ts-480 setting. However I'm having trouble with transmit audio - there doesn't seem to be any. Same with the qdx setting and regardless of vox or qmx threshold or tablet volume.

Ft8cn works with the kx3 and wsjt-x works with qmx.

I thought I read something about L/R channel in the qmx. I haven't been able to find that reference again. I'm wondering if ft8cn might use one channel and qmx uses the other. Still pondering how to get it to work. Next I'll try another android device.?

On Tue, May 21, 2024 at 11:14 AM, Ben KO4BHX wrote:

I use the emtech ZM-2 ATU with my QMX. Similar size and style, 15 Watts, 80m - 10m, I have found it works great for my needs.

This statement from Emtech's website is a bit disingenuous:

"The ZM-2 will tune all bands from 80 to 10 meters."

Meaningless. And silly. Even if it "works great."? The tuner isn't adapting to a "band" of operation.? It's adapting to a complex impedance at an operating frequency.? Emtech should either leave that marketing bullet-point out or specify a complex impedance range.? But, it's easier to sell it this way without a full complex impedance analysis. ?And gullible hams buy into it.

The same inaccuracies apply to manufacturers that sell their tuners based on being able tune a 3:1 SWR or 10:1 SWR, for example.? The quoted SWR have an infinite set of complex impedance combinations.??

Paul, W9AC

?

On Wed, May 22, 2024 at 03:02 PM, Ted 2E0THH wrote:

Hi Jim
He actually says twice that he hasn't optimised the power.
73s Ted
2EOTHH

Even unoptimised those numbers are very low. Less than 1W on a number of bands. I would expect 3W minimum assuming three toroids are all wound as per the instructions and to a decent standard.?

On Wed, May 22, 2024 at 08:26 AM, Yury Krasouski wrote:

KNIPEX Stripping Tweezers for coated wire (15 11 120)

It looks like this tool comes with a 0.6mm blade, which I'm assuming will work perfectly for the 0.6mm wire in the QMX+ kit.

The smallest blade they sell for this is 0.5mm, so this probably won't work for the 0.33m wire in the QMX+ kit?

-Dj

I imagine that there will be multiple iterations of 'tricks' in coil windings put forth by the more experimentally-minded contributors as well as enhancements by Klaus to the firmware.

...now if someone wanted to add the 10 watt amplifier....
--
Tisha, AA4HA

Hi Jim
He actually says twice that he hasn't optimised the power.
73s Ted
2EOTHH

I am in the process of winding the output transformer for my QMX using the instructions at .? I am trying to wind it as a RWTST. However, the dimensions don't seem to work out. Started with 25 cm of wire. After Step 2, I have 7 cm sticking out of each side of the binocular core. I then cut a 20 cm piece of wire (Step 3). Laying that next to the binocular wire means there are 3 cm of "extra" wire sticking out beyond each side of the binocular wire.? That doesn't seem correct. What am I missing ?

Thanks and 73,
Steve, N2IC

Feel free to join the thread on this topic already in progress here: ?/g/QRPLabs/topic/106111415


73, Mike KK7ER

On Wed, May 22, 2024 at 02:11 PM, Brian Kassel K7RE wrote:

Another great deal on a pre-built LiPo 3S battery pack is at

a place called "Battery Hookup":

?

?

Only $ 2.00 for 3S 2200 mah with BMS, enclosed in a

tube. These are surplus, but at that price a person can buy several.? They are fully protected and can be charged easily .

I have had several dealings with them, and can recommend them highly.

I have no connection with this establishment etc.

Bear in mind fully charged they're 12.6V so care is still needed when using them with a QMX

Just watched a YouTube video by DL9SCO on his successful build of the new QMX+. I’m curious about those power out figures he showed - kinda low on most bands, especially 160, 80, and the three highest bands.

Hans - is this just an anomaly with his radio, needs tweaking, or is this the expected power from this rig?
--
Jim / K7TXA
Eagle, ID

SKCC 10447T
BUG 301

Also, it would be good to know what the overall power draw is of your QMX during RX and again during TX (you can put it into a TX test via PutTY diagnostic session). A DMM in series with your power supply should provide those readings.?

Be sure you connect a 50 ohm dummy load to your QMX while doing any tests.?

Also let us know if it's a 12v version (presumably it is) and what Rev pc board was in your kit.?
--
73
de Roy - KI0ER
Littleton, Colorado USA

Hi Hill Billie Ham

On the rotary encoders, check each lead with a DMM for a short to the case of the encoder body. There should be no continuity from any encoder lead to the body of the encoder. It's usually easy to fix but that issue is easy to create also. It happens to the best of us!?
--
73
de Roy - KI0ER
Littleton, Colorado USA

Hi,

There is dedicated tool for this: KNIPEX Stripping Tweezers for coated wire (15 11 120). It has different set of replaceable tips for corresponding wire diameters.

But, I did the similar tool using good quality nail tweezers but add a small recesses for different diameters using file.

Can't wait for mine too!

73
--
David Thomas M0OOR

Roderick,

there are also some suspicious solders with enamel (some examples marked red).

73, Ludwig