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Re: QMX+ with 100 amp/hour lithium iron battery

 

On Sat, Apr 12, 2025 at 08:41 AM, Braden Glett wrote:
I live on a 20 acre horse ranch where there is absolutely no neighborhood RF noise, and even in that low-noise environment, I cannot detect any noise from the Drok.
I keep a supply of 100pF and 1000pF NP0 leaded capacitors handy.? It only takes a second to tack-solder a couple onto a board or slip them into terminal block connections to help with RF bypassing power supply outputs.
It is easy to add leads to chip caps, which is essentially what the epoxy-dipped caps are, if that's what you've got.
73, Don N2VGU
Re: Winlink and VARA HF setup for QMX

 

I also just made this post with some Winlink VARA-HF setup details:
/g/QRPLabs/message/143063
Stan KC7XE
Re: QMX and WinLink/WARA HF settings

 

Petrov, I use the following VARA HF settings in Winlink:
For when the picture gets deleted:
Radio Model - Kenwood Amateur, USB mode (not USB Digital), Use Internal Soundcard
Select appropriate COM port; baud rate doesn't matter, do not enable RTS/DTR
PTT Port: Kenwood TS-590S? (I think others would work too)
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And in the VARA soundcard settings:
- Choose the Device Input and Device Output entries with QMX in their name
- I choose L+R output (though I don't think this matters)
Tune Drive level: set to maximum (0dB).
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Also, in Windows sound devices, set the QMX 'playback' and 'recording' device levels to 100%.
You can get to this setting easily by typing mmsys.cpl in the windows search box (this brings up the flow-level windows sound control panel).
?
I also found that in Windows, the audio output level created by Winlink's VARA-HF modem does not seem to be full scale, so the output power is somewhat lower.?? It would be nice if Hans could add a level adjustment to the USB sound interface, so we could compensate.
?
Stan KC7XE.
QMX+ PA Voltage: Software/Calibration Bug?

 

My QMX+ (Rev.3, 12V, FW 003) complains about low voltage at the finals. See picture: 9.7-9.8V in red.
I checked the voltages at C506 and C529 and they show the expected divider ratio of ~5.7:1. But the actual voltage at C506 is ~11V (12V regulated power supply).
May be this is one of the reasons for the SSB calibration problems?

Gottfried oe1ira

PA_V.jpg

Re: QMX+ with WA3TFS amplifier

 

Both the QMX and QMM+ share the same software.? "PTT to TX delay "is in the SSB menu.? It appears to be applied in CW mode also.? If you are using CW you might want to turn on Semi QSK and put a value of around 700mS in Custom QSK so that you are not beating your amplifier relays to death.
?
Brien - KE7WB
Re: 60-15m QMX wound inductor attachment question

 

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The manual is very specific and there are plenty of pictures. Each toroid has a set number of turns. Follow the instructions. Prepare the ends by scrapping and heating the end when you install?
them. After each toroidal is installed, measure for continuity. The instructions are very complete.

On Apr 12, 2025, at 2:45?PM, Andrew (W3AWC) via groups.io <callsign.W3AWC@...> wrote:

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Hi All,

I'm very new to building kits, and radios in general. Working though my 60-15m QMX and I am at step 2.12 where I am winding and attaching L511, L506, L512, L508, L513, and L510 and I wanted to confirm that winding number 0 should go on the outside through hole for each inductor and the final winding should go through the hole that is closer to the center of the toroid?

This seems to be the way it should be, following the instructions from L502 but I wanted to be sure since I have not been able to find a clear picture online showing how these inductors are mounted and there are not explicit instructions in the manual for these specific attachments.
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Thanks in advance!
Andrew

--
Gary W0CKI
Re: QMX+ Firmware laden

 

Hi Volkert,
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Sorry to hear that you're still having issues with the driver.
I use a Linux operating system and try to avoid using windows as much as possible.
I'm sorry, I don't have a windows 7 system to assist you with the specific issue you have encountered.
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However, please read this guide. This might help you.
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Regards.
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Mel. M0KMD.
Ham Radio Crash Course is building a QMX tonight!

 

Popular American West Coast Youtuber is building a QMX on stream tonight at 8 PM EDT (US East Coast Time).
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Seems like it might be of interest to the group.
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https://www.youtube.com/watch?v=7iOY1p7flPU&lc=Ugw2vcdWfQbWKblZc_R4AaABAg.AGomNNvKyjwAGpN0n8kGVR
Re: 60-15m QMX wound inductor attachment question

 

If my memory is correct, yes. Make sure you have scraped/sanded and tinned all the magnet wire before installation. Use sufficient heat, with a large tip.
.rr
Re: QMX+ with WA3TFS amplifier

 

A mistake on my query - this refers to the QMX NOT the QMX+.
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Question then: can the transmit delay be adjusted ??
?
73, Jamie
WB4YDL
Re: 60-15m QMX wound inductor attachment question

 

Hi va3rr,
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Thanks for your response. So it looks like in your picture the top left toroid of the 6 inductors I can see the final tun goes through the center through hole. Is this the case for all of the toroid inductors?
?
Thanks,
Andrew
Re: QMX and WinLink/WARA HF settings

 

It is very strange. As I said when I used Vara sound card settings where QMX was mentioned as output/input device TX power was very low. Than I decided to choose mic and dynamics as input and output device in VARA soundcard settings. And TX power became normal! Around 40 Volts peak to peak. Ans VOX was OFF! So I transmitted some signal, but I am not sure what signal it was? and was it not distorted or not. At least I didn't manage to make a connection.?
I tried to switch VOX on and found out that it doesn't work. Even during normal SSB communication it doesn't activate TX. So now I am really confused....?
One more question. There is no Kenwood 440 in VARA list of transivers. So I've chosen Kenwood 550. Is it OK?
Re: 60-15m QMX wound inductor attachment question

 

Each turn thru the toroid hole counts as a turn. The toroids must be wound in the direction shown in the manual. Here's some pics of my mid-band QMX.
GL de va3rr
Re: QMX+ with WA3TFS amplifier

 

Brien:
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Thanks so much for this. I suspected this was the case. I actually jumpered the diode at the relay in the amp to put in transmit mode, and the QMX+ worked perfectly fine. I need to upgrade the firmware as well. I’ll play with the delay a bit and see if I can get things calmed down.
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73, Jamie
WB4YDL
Re: QMX+ with WA3TFS amplifier

 

If you are using COR function with the amp this will happen as the QMX sees a high SWR while the relays are switching over.? ?If you can use PTT input into the amp and set a TX delay of about 15mS on the QMX it will work.
?
Brien - KE7WB
60-15m QMX wound inductor attachment question

 

Hi All,

I'm very new to building kits, and radios in general. Working though my 60-15m QMX and I am at step 2.12 where I am winding and attaching L511, L506, L512, L508, L513, and L510 and I wanted to confirm that winding number 0 should go on the outside through hole for each inductor and the final winding should go through the hole that is closer to the center of the toroid?

This seems to be the way it should be, following the instructions from L502 but I wanted to be sure since I have not been able to find a clear picture online showing how these inductors are mounted and there are not explicit instructions in the manual for these specific attachments.
?
Thanks in advance!
Andrew
Re: QMX and WinLink/WARA HF settings

 

Thank you Hans! Yes, I tried to use DiGi by mistake )) Now I tried USB and there is strange thing: it works, but TX power is very low. Peak to Peak voltage is just 3 Volts. When I work in other digital modes (FT8) its is ok - 40 Volts peak to peak (40 m band). What it can be??
QMX+ with WA3TFS amplifier

 

I recently built the WA3TFS linear amplifier featured in the March QST. The build went very well and with my old MFJ 20M QRP CW radio, 3W in gives 20W out with a peak 4A draw. So, I tried to interface my QMX+ to it and was surprised to see the QMX+ stop transmitting after the first dit. It would recover after a time and would transmit fine by itself or through the amp but it didn’t like it all when I activated the amp. The firmware hasn’t been upgraded in awhile so I’m not sure if this has already been addressed. I’m not sure the RF detection is maybe not fast enough ??
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Any ideas appreciated.
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73, Jamie
WB4YDL
Re: QMX+ microphone ideas

 

Good info! I just ordered two.?
Re: QMX+ microphone ideas

 

Hi les,
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That is the same mic, (I have 4 of them), I use on all of my Bitxs and my QMX+. I always get good audio reports. I know they are not the most attractive looking mics around but they do work.
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Joel
N6ALT
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