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Re: Perfect tiny backpack setup? #qmx
Jim, as a followup, I did just find this answer ( https://groups.google.com/g/digipi/c/u7cczaULk8o/m/1Q5pRooWAwAJ ) to the question of running logging programs on DigiPi, from its creator: The extra
By Leigh KG7WED · #109990 ·
Re: #qmx Antenna Tuner Can Kill PAs #qmx
John, A couple of things. First, how are you getting the mosfet dissipation from the spice simulation? Are you eyeballing an instantaneous power (Vd * Id) waveform and doing a mental
By mux_folder2001 · #109989 ·
Re: QDX PA modification with 2x IRF510
While RD16 is a good RF device it offers nothing is switch mode (class-d) service as it has a poor Rds-on which is typical of RF service devices. Note: the RD-16 has a breakdown voltage of 50 Volts,
By ajparent1/kb1gmx · #109988 ·
Re: How many radio hams does it take to change a BS170 ?
Yeah I forgot that one ;-) -- - 73 de Andy -
By - Andy - · #109987 ·
Re: QMX Assembly Manual Revision I???
Check out the last page of the manual.
By Mark Volstad - AI4BJ · #109986 ·
Re: QDX transmit troubleshooting advice¡­
Hello John Isn't the calculation fraught with difficulties? Where did the 0.5 microseconds assumption come from? Wouldn't that depend on the effective resistance to ground of the parallel BS170s
By Hans Summers · #109985 ·
Re: Progrock 2
I should add the 5v is from the usb micro lead.
By rogerlaw159@... · #109984 ·
Re: Progrock 2
I'm running it on 5 volts so perhaps I should raise a ticket?
By rogerlaw159@... · #109983 ·
QMX Assembly Manual Revision I???
I just noticed that Revision I of the QMX assembly manual has been published.? I haven't seen anything posted here about it.? Can Hans - or someone else - tell us what has been revised? I'm halfway
By Jonathan Poland · #109982 ·
Re: Intermittent Dit on QMX
Not sure if it is related but there is a lag on sidetone implementation with keying in iambic mode much above 16wpm which causes errant keying. Hans is aware of that issue. Not saying it is the same
By Daimon Tilley · #109981 ·
Re: #qmx Antenna Tuner Can Kill PAs #qmx
Hi Evan, This is my take of QDX class D amplifier as an experiment. I am using FDT86256 mosfets instead of BS170. The driver is different than QDX. As I said it is just an experiment board. It is not
By Barb WB2CBA · #109980 ·
Re: Progrock 2
Hi, About a week ago in a project I simultaneously fired up two ProgRocks - each with 3 outputs enabled - from an 11-ish volt supply - this was from a 12.0 volt supply with two diode drops as the
By cct314159@... · #109979 ·
Re: #qmx Antenna Tuner Can Kill PAs #qmx
Barb, Is the IR image off compared to the background?? The hole in the upper left corner is off by about the same amount as the two hot spots that could be the transistors.? It could be that the
By Evan Hand · #109978 ·
Re: #qmx Antenna Tuner Can Kill PAs #qmx
That is my issue here. Class D and Class E amplifiers should have relatively little heat generated compared to AB1 or AB2 amplifiers, based on my understanding of relative efficiencies . I suspect
By Lee · #109977 ·
Done with the build and it wooorrksss :)) Have a strange issue with volume control #qmx
Hey guys. I have just built my new QMX and it works just fine except the volume control. I have read somewhere in the threads that it is a software issue and will be fixed on the next firmware, but if
By Kiril Miloshev LZ3OM · #109976 ·
Re: #qmx Antenna Tuner Can Kill PAs #qmx
Ted, I am a bit lost too! In previous posts there was an inquiry for heat map of BN43-202 binocular during tx so I had those flir photos of my design which guves similar tesult as QDX. I thiught this
By Barb WB2CBA · #109975 ·
Re: Progrock 2
Mine runs cool. Or at least, I haven't noted any heat of significance. Low current draw if it's running right, should mean little heat. Are you running it from USB or an external source? Brock
By Brock VA7AV · #109974 ·
Re: #qmx Antenna Tuner Can Kill PAs #qmx
Hi Barb Assuming that the current consumption is per spec (c.650ma on TX) wouldn't you expect this sort of heatmap after a continuous 5 minute transmit? It looks like the design is working just
By Ted 2E0THH · #109973 ·
Re: QDX transmit troubleshooting advice¡­
Chris, & all here, Here is a fun exercise: Assume that no commutating diode is present at L14 in QDX, and that, for convenience, the PA is drawing 1A through L14. Then at the moment the last BS170
By John Z · #109972 ·
Re: Progrock 2
Roger, Fed with USB 5V? Mine takes around 30mA. Shows as a COM port? Mine seems cool but difficult to tell the way it is mounted. 73 Alan
By Alan G4ZFQ · #109971 ·