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QMX+ VOX 5
I waited for and yesterday installed the 1_02_000 firmware. I did a bit of tinkering with the EQ to get some more emphasis in the mid-range (and worth noting that when I do live sound at folk dance events, I always cut back the bass and emphasize, not too much, mids and highs to improve intelligibility of the dance leader, just as Hans suggests). And I made 4 SSB contacts on 20 meters with some Italian stations in a contest setting .... running about 75 watts with the QMX+ and my HR-50+ amplifier. Worked great. Thank you, Hans ... you are a wizard! One glitch ... I cannot get VOX to work. I'm using one of Erik Larsen's microphones, which clearly works fine in PTT mode and sounds OK. I set microphone gain using the built-in Mic Test ... goes red on just the loudest peaks. On USB, speaking into the microphone apparently triggers the VOX, but it then cycles on and off until I manage to get QMX+ mode out of USB over to LSB. LSB doesn't work at all ... speaking into the microphone does not trigger VOX. Input device is set to "External Microphone". And I'm using TRS (stereo) 1/8" mini cable between the microphone and the QMX+. Any hints will be much appreciated! Thanks - Bruce K1FFX
Started by Bruce K1FFX @ · Most recent @
#QMX+ MIC circuitry improvement
Hello QRPers I would like to suggest an improvement I did in MIC circuit in my QMX+. Existing circuit is quite simple and powered from not very clean VDD. By adding two capacitors (100n, could be more) and two resistors (33k, 1k) I was able to reduce the audio noise on the other side receiver by 6 to 8 dB (simple check with Audacity peak meter on two recordings, before and after, FT-891 as a receiver). This will improve SSB signal, especially on higher bands (low band noise). I assume the same will apply to the internal mic circuit. It would be also good to use filtered VDD, same as for microcontroller ADC (from C214), but I did not wanted to have a wire across the board. Maybe a separation resistor on the microcontroller key/paddle line can also help but I think most of the noise is getting in because of dirty digital supply used for bias. I think it is worth to consider in case of next PCB revision, both QMX and QMX+. 73 Pawe? SO8FM
Started by Pawe? H @
#qmx #problem #troubleshooting #troubleshooting #qmx #problem
Hi everyone, I've been using my QMX for about an year with great joy and happiness when suddenly my QMX stopped receiving or transmitting. I'm fairly new to radio and i am struggling to find the problem. The sweeps are all garbage on all freqs: RF filter sweep, Audio Filter Sweep, everything but the LPF sweeps. The Voltages seem good although when I press "T", the transmitter voltage shows 9.8v in red. My QMX is 12V. I have little knowledge and i need a hand from you guys, to know where to start. I zipped and attached the image sweeps. 73 Pedro - CR7BJL
Started by Pedro - CR7BJL @
Firmware updated to 1.02_000 - QMX has changed from 60/40/30/20/17/15 to 80/60/40/30/20? 4
Hello! As the title says, I've just updated the firmware and now seeing my radio is showing as 80/60/40/30/20m rather than the 60/40/30/20/17/15 version that was built. I wondered if anyone has any ideas of how this might have occurred? Many thanks! Alastair 2E0UOE
Started by Alastair Moore @ · Most recent @
QMX gets a full POTA trial 6
Park US-3843 today, central NC. Low humidity after yesterday's storms. Slight breeze. QMX built for 9w Dork regulator DROK Adjustable Voltage Regulator... https://www.amazon.com/dp/B089ND7PTH?ref=ppx_pop_mob_ap_share Bioenno 9v battery SOTA Beams Bandhopper Palm pico paddle Why I love this rig: even though it is menu-driven, it seems SO INTUITIVE that it doesn't seem difficult to do what I want. Hans must have done some serious human factors analysis with the rig. Also, the receiver is outstanding. I made 24 QSO in 45 minutes on 20. The beacon CW message capability is superb. Thanks to all for the Drok regulator suggestion. And thanks to Hans!! Mark Lunday wd4elg@...
Started by Mark Lunday, WD4ELG @ · Most recent @
lightAPRS22 2
Can I ask Questions about this here? https://qrp-labs.com/lightaprs2 Or is there a separate group to discuss this tracker? Joe WB9SBD
Started by Joe WB9SBD @ · Most recent @
installed firmware version 1_01_009. Ran full configuration. Bad things happened. 10
My QMX+ was built by QRP-Labs. It has worked well for about a month, listening and practicing CW. Today I upgraded from 007 to 009 and ran the full configuration routine with a dummy load. The radio felt warm, not hot. It is connected to an OCFD antenna with a SWR a bit below 2.0 on 10 meters. I cancelled Practice Mode, started sending QC while monitoring the SWR (about 1.8 on the display). After about 1 minute, the QMX+ shut down. When I turned it on again, the display grid was all black dots. I removed the cover and adjusted the display pot so it was readable. Turned the radio on and sent CQ a few times. After about 10 seconds the radio shut down again (and again, and again). I performed the factory reset (Twice) and reconfigured the QMX+ for my key and display options (SWR and battery). At this point the radio will power up, the display looks correct and the menus work. CW Practice Mode works, except each character is followed by a loud POOP! Transmitting CW or SSB causes the radio to reset and sometimes it shuts off. Any help is appreciated. Be kind (I've had a difficult day) 73
Started by Steve AI7SV @ · Most recent @
QMX+ not receiving on 10m 13
Hello all, my QMX can tx fine on 10m, but I can't even hear ft8, come to think about it, I have never heard anything on 10m. Here are some screenshots:
Started by Nico Smith @ · Most recent @
QMX Not Appearing As USB on Mac OS 20
Unbelievable - I've been doing firmware upgrades on all my QMX, QMX+, etc. rigs on this Mac Mini since the dawn of time - no problems. Well, tonight I downloaded the new v2.00 firmware and was going to update one of my QMX+ rigs and give it a whirl. No problem downloading the file. he problem is that now my Mac Finder refuses to see the QMX device. PuTTY has no problem connecting to it; MacLoggedDX has no problem connecting to it. But unless Mr. Finder see it, there will be no way to move the new f/w over to the radio. I've even re-booted the computer - no joy. I have not changed anything on this computer nor have I done any system updates. Any suggestions? -- Jim / K7TXA Eagle, ID SKCC 10447T BUG 301
Started by Jim Bennett / K7TXA @ · Most recent @
QMX+ with WA3TFS amplifier 37
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 ?? Any ideas appreciated. 73, Jamie WB4YDL
Started by James C. Hall, MD WB4YDL @ · Most recent @
QMX plus - just did it in 5
... by supplying 30 Volts by mistake. :-( . It generated an ugly smell. The QMX plus is now completely dead. When opening the case I saw that a component next to the DC connector was cracked and deformed. I also smelt real bad and is labeled "LG". Whatl else might be damaged - or is it FUBB? In which case I might have to order another kit.... (?) 73, Holger, Dk4LX
Started by DK4LX Holger @ · Most recent @
SWR overshoot and SWR protection 7
The following report is for the latest (SSB-)firmware 1_02_000, 80-20m band version and SSB-mode. When transmitting in dummyload or resonant antenna, the same occurs: At the beginning of the transmit the SWR-meter of the QMX overshoots to maximum level for a very short time (about half a second) and then goes down to the real SWR. Generally not a big problem. But on 80m band the SWR protection kicks in every third or so TX-cycle. I think it is because of the overshoot(?). The other 4 bands do not have that problem Has anybody experienced the same?
Started by DH1MFS @ · Most recent @
QRP Labs QMX SSB Firmware Is REAL!! 7
Thanks Mustafa TA2MUN for sharing this one with me! The enthusiasm is so infections, might even get ME on SSB eventually! https://youtu.be/P09N-t1U1-E?si=xLUi5bMmboDOEnrL&t=396 73 Hans G0UPL http://qrp-labs.com https://www.buymeacoffee.com/g0upl
Started by Hans Summers @ · Most recent @
Why I think QMX Calibration Kills PA 25
I just hooked my scope up to the drain of one of the PA transistors in my QMX+ and kicked off a 160M Phase cal (O button). I am seeing 120 volt spikes during the cal. Here is a link to a screen shot from my scope: 160PhaseCalGlitch.jpg This is going to fry some BS170s for sure. Tony ADoVC
Started by mux_folder2001 @ · Most recent @
New Chat: K6ARK Mic #chat-notice
A new chat has been created: I am new to the io system so forgive me if I¡¯m in the wrong place. I understand that someone here builds the K6ARK microphones. I would like to buy one. By: Daniel Garner <debay777@...> 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.
Started by Group Notification @
Failed software upgrade-help! 12
Well I have done it again. My QMX mounted. I deleted the old firmware and copied the new SSB version. I did notice there was another file that started with e. I emptied the trash and checked the contents of the mounted QMX volume. It was empty. I started to recopy the firmware and the QMX unmounted. It will not mount, nor will the unit turn on. What have I done and how can I fix it? Jim
Started by Jim Brown @ · Most recent @
Feature request: Band select by Tune knob 7
Hi all, Long press of Select enters the Menu system, displaying "Audio" (or whatever). But while still pressing Select, turning the Tune knob could exit the Audio menu and instead, select another band, up or down depending on the turn direction. This would be handy, especially using the QMX+ which requires 11 Vol button double presses to go down to the next lower band. -- 73 Matti OH6BEX
Started by Matti OH6BEX @ · Most recent @
Fun QRP SSB POTA Activation with QMX mid-band
It really does work well! Thank you again, Hans! Activating Saguaro NP in Arizona with SSB was fun! https://www.facebook.com/share/p/1N3Lr332Pg/
Started by Stan Dye @
QMX+ Assembled, Updated, but ADC I/Q Most Tests seem Way Off 13 #build #test #toroid #transformer #troubleshoot
Greetings! First post. I'm a seasoned electronics kit assembler with above average skills. That said, I have virtually NO skills with radios, but am a quick learner... I'm confident the electronics assembly is OK, but unsure about the coils and possibly enamel coating issues. This is a screen cap of the results from ADC I/Q test: Based on the 1_00_027 operation guide, this should be a pair of sine waves slightly timed differently. All of the bands are pretty similar, and most tests are way off like this. I suspect the trifilar phase splitting is shorted and needs rebuilt, but wanted to make sure before I redo it. My concern is that when I twisted the 2 wires together, I used a drill and may have wrapped them so tightly the wire cut through the enamel coating. In the Operation guide, it seems to indicate this trifilar phase splitting transformer tends to be involved when multiple tests are not normal. What do you think? And THANK YOU in advance!
Started by Ahand59 @ · Most recent @
Michigan QRP Week Zoom Chat 2
There will be no MI QRP Chat on May 8. It is reserved for the Club¡¯s Annual Meeting. We had thirteen folks join the MI QRP Zoom Chat on 1 May. Please join us Thursday May 15 (and every Thursday) at 4PM Eastern for the Michigan QRP Club weekly QRP Chat where the main topics will be QRP and other ham interests. New hams are encouraged to participate and ask questions. It's fun, it's easy, and it's free. You only need a computer, a smart phone, or a tablet that can connect to the Internet. OR if you can't be close to any of those you can join by audio with any standard phone. Just follow the directions below. No software needs to be loaded or installed. Anyone can join and non members are welcome. Details are here: https://www.miqrp.net/zoom Zoom ID: 811 0835 6229 Pete WK8S Ed AB8DF Ernie NE3TE Stan WB8QJZ Casey KC9IH Dave N8SBE Stuart M0SGV Yvon AE7YD Jerry KI4O Bill N5IM Harry K9DXA Robert G0RYL John KC1VPP Bill from TX showed up for the second week in a row. Stan has not been doing much with satellites recently. Not that many passes right now that are capable of doing slow scan TV. New Yaesu QRP rig coming out? Will we see it at Hamvention? There was a leak that there is a companion 100 watt amp. Dave had an old 817 and now has 818. The Elecraft KPA100 amp works well with it. Others use a Hard Rock amp. He has been watching the Rat Pack videos and they have a lot of interesting stuff https://www.ratpac.us. The most recent one was all about packing for POTA. This was Roberts first time in the chart. He is a homebrew builder. Currently playing with a one tube (valve) regenerative receiver. Stuart has his Michigan Mighty Mite working and will try to get it on the air soon. John is new to the chat. His QTH is in Connecticut. He needs CW practice. He has a QRP Labs rig. Yvon is playing with his new ZBitx. So far he is not impressed. Bill did a POTA this week. The mosquitoes were bad. Used a QMX rig and Ham Sticks which is modified to use a telescopic whip. Ernie suggested trying a performer vertical set up to help get better resonance. Harry just finished a QMX+ and it is not working. Others have been able to get SSB to work on their QMX+. He likes using his Ham Sticks for his POTA operations. He also uses the magic carpet approach. https://www.jpole-antenna.com/2024/01/13/this-is-the-new-magic-carpet-faraday-cloth-ground-network/#google_vignette Ed uses one of these adapters https://www.cometantenna.com/product/comet-ad-35m/ with a mag mount. He puts the mag mount on the roof of his car and the adapter allows radials to be attached. Much better than just using the capacitive coupling of the mount for a ground plane. There will be no MI QRP Chat on May 8. The topic for Thursday, 15 May will be TBD. The agenda for the 15 Mayl QRP Chat: Ernie to do a short introduction and acknowledge any new folks to the Zoom chat. The topic for next May 15 will be an open forum. During the open forum anyone can take the floor. We will go one by one until all have had a chance to have the floor. Files, pictures and presentations can be shared if you have any. Please try to stay muted when someone has the floor. Thanks Ed AB8DF
Started by Ed Kwik @ · Most recent @
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