Thanks a lot, Johan and Yury! :)
I should get it next wednesday ... ;)

Cheers,
Torsten


Am 24.05.2024 um 10:20 schrieb Johan Bodin:

--
vy 73 de Torsten | DB2TE, formerly DO4TE

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Hi Timo,

A couple of questions:
What is the board revision?
What version of firmware?
Does the receiver work (decoding the FT8 signals)?

My first thought is that a capacitor is open or short in the PA's output stages. There could also be an issue with the voltage doubler circuit (D7, D8, D9) that is shorting the output.

Verify the cables and test setup to ensure you do not have a test instrument (dummy load) failure.

73
Evan
AC9TU

My high band QDX have been up and making contact for probably more than a year now.? It just suddenly went from a healthy 4.5w on 17m to 0.5 w, and that is on all bands, not just 17m.? Amps in RX are 170mA which is standard for my QDX.? With the current TX problem, I am experiencing amps now shooting up to well over 1A, where it used to be around 600mA in TX.

This what I have done so far,

Replaced IC5 twice.

Replace all 4 bs170’s twice,

Confirmed 5v PTP with an oscilloscope on the gate of all 4 bs170’s.

Replace diodes D7, D8, D9.? They measured correctly after removal, so this was not required.

Replaced q6, also not required as it was not blown.

Removed and rewind T1.

Confirmed voltage from L14 to T1 and onto the drain of all 4 bs170’s.

?

The problem does not seem to be on the low pass filters as I have the same 0.5w for all bands (10 to 20).? It must be something that prevents the signal from reaching the low pass filters and basically creates a short to ground and therefore the high amp usage.?

Lost at this stage.

ZR6TM

Timo

Thanks for the replies, glad I'm not alone. Will continue to power up the GPS and U3S separately as that seems to work.

73's
--
David Thomas M0OOR

Torsten,

it is easier to identify the winding if the wires have different colours. I managed to find red and green 0.25mm enameled wire in my junkbox which I used together with the wire supplied in the PA kit (for both T201 and T202).

73 Johan SM6LKM

Hi Torsten,

You can order alternative enameled wire. But just make sure, that you choose wire with ability to burn out of enamel during constant heating of solder tip. Most of enameled wires should be scratched to remove enamel before soldering.

I really enjoyed that Hans thank you for sharing!
73s
Ted?
2E0THH?

Hi all,
?
Next Monday, May 27th, is the next QCX Challenge at 1300Z, 1900Z and 0300Z (Tuesday).
?
See all info here :
?
Join the discord page in the #qcx-qrp-operation channel to post your QRG or exchange other info, or just have a chat with other QRP Labs friends ...


Enter your scores at

Note that I will be on the road to the Ham Radio fair in Friedrichshafen in June, and still have a lot to prepare for that trip.
I will not be able to send messages or participate in the QCX QSO parties, so please mark your calendars :

QCX Warc Party is June 10th. ?
QCX Challenge is June 24th.

73 es GL,
Luc ON7DQ

On 23/05/2024 19:02, Da Amazin' man G0FTD via groups.io wrote:

Pass something like 200ma through a 1 amp rated diode will only get you about
0.3v of drop

DMMs with a Diode range give about 0.7 volts for a 1N1007 with maybe 1mA flowing depending on the meters.
About 1.0 volts at 1 Amp.

An interesting thing is that when measuring a voltage with a modern 10M Ohm input DMM there is less than 0.01 volts drop across a diode placed in series.

Use a 10M Ohm meter in a simple QRPp RF power meter, no compensation required.

Amazin.

73 Alan G4ZFQ

Good morning everybody :)

while assembling T201 one of the 4 0,25mm wires broke, so I can't build T202 now.
Are there any special specs for the 0,25 wire, or can I simply order some at reichelt.de or so?

Cheers,
Torsten

--
vy 73 de Torsten | DB2TE

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To access Log files, tap QSO logs at the bottom of the screen.
Tap the arrow in the top left corner of the log page.
Follow the instructions on the screen to access the files from another device.
You can then import them into your main log.
Hope this helps.
Colin
G4ERO

Hans, et.al.,

Any help would be appreciated...

I recently built and checked out a 2023 QMX Rev 2 (80-20m, 12V) to the point where everything I tested (including GPS Viewer, WSJT-X) was functional (made the "Rev 2 QMX PCBs shipped in 2023" diode mod). Was feeling real good about the build, and even wrote a message about the Paddle connector using Straight key with mono jack issue...

Then I decided to update the firmware from what I started with (1_00_018.QMX) to the latest (1_00_019.QMX). My initial check was to run the Terminal Hardware tests - and now I have what appears to be a catastrophic audio problem. Reverting back to 018 firmware does not fix the problem(s).

Here's what I've found so far:

• Audio filter sweep - All bands flat lines at -165
• Image sweep - all bands flat lines at -165
• RF filter sweep - hangs after getting to 0% and no plot at all; QMX is now hung and only cycling power works to restart the QMX
• LPF sweep - all bands look nominal, there is RF output at the 50 ohm load
• SWR sweep - all bands look nominal into a 50 ohm load
• CW mode - can hear sidetone in headphones, can see signal at 50 ohm load
• No audio over CAT using WSJT-X (waterfall is flat), no audio in headphones (WSJT-X was working yesterday prior to firmware update)

The RF filter hang-up requiring a power cycle is what gets my attention, followed by no receive audio in any band by CAT (WSJT-X) or and sound in headphones other than start-up clicks and CW sidetones. RF signal output, power and SWR all look same as before "the event".

Have tried multiple System resets, have tried downgrading to firmware 018 (multiple times), have tried enabling ALL in system log for bread crumbs. I have a good oscilloscope, but probing SMD is not easy... I've built multiple QDX's, a QCX+, clock kits, and never seen the firmware hang ever before.

What could cause all receive audio to go dead (and not transmit CW sidetone) AND the RF filter sweep to hang? Looking for suggestion to isolate between STM32 and other receive audio components. Would a failed receive audio component cause the RF filter code to hang?

Thanks in advance,
Paul
AB3XL

Whenever Hans releases a new kit I order a printed color manual on line.? I did that this time but received two Transformer manuals from the [printer.? I love the color directions.
I will send to someone this manual for $1.00 to pay for media mail.? Paypal to this address.? Email me first in case of multiple requests.

Have fun.

Bill, WA8CDU

I was asked for more info on the different wattmeters used. The original measurements were made with a no-name import (cheap) QRP watt/SWR meter. I had used this meter the entire time I have had the QDX pair and had assumed it was correct. ?Another ham asked if I had tried another meter…..no, because this was all I had. ?He loaned me his MFJ meter which I used for the updated readings. He said he was confident it is correct based on comparisons to his other wattmeters.

Tnx, ? Robert. KR4VT

Hans, et.al.,

Like several straight key users (wish I really knew CW, just using the key for build verification ;<), I have noted that the Keyer configuration (Firmware 1_00_018.QMX) requires "Keyer mode: Straight" and "Strght mode: Ring" when a Straight Key with a mono jack is used, which is counter-intuitive as a mono Jack shorts the Ring to the Barrel.

As to why, both the schematic (schematics_rev3.pdf - "Microcontroller and digital sections" on page 2) and Assembly (assembly_1_04.pdf - "Main board diagram on page 8) show that the Paddle connector TIP (X202 Pin 2) is connected to signal "KEY_DAH" and the RING (X202 Pin 3) is connected to signal "KEY_DIT".
However, the Operation Manual (operation_1_00_018.pdf - Section 2. Paddle connector page 7) "Paddle connections" diagram indicates TIP: Dit and RING: Dah. Also, as stated above, a Straight Key with Mono jack requires firmware configuration of "Keyer mode: Straight" and "Strght mode: Ring".

In summary, it appears the Operation Manual "Paddle Connections" diagram for CW Operations has the "Dit" and "Dah" swapped (based on schematic and main board diagram) and that a firmware update would be nice to make "Strght mode: Tip" for a Straight Key with a Mono jack.

Not a particularly significant problem as most users have already discovered the 'fix', but would be a nice update to include the next firmware and Operation manual updates.

I really enjoy building the QRP Labs excellent kits!

Best regards to all,
Paul
AB3XL

Some months ago when building my HB QMX I made some calculations and a lot of tests to the same problem. Maybe this could be helpful. There is also a statement by Hans.

Hi Todd,

I chose sma over BNC due to size constraint. Sma can be converted to BNC with adapters easily which was also plus on my decision to use sma.
--
?

73, Barb

开云体育

Hi David,