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Re: BS170 Fail
I have on of those QRPGuys SWR indicators. I've just not built it, yet. I wonder if I should us that or find and absorptive bridge. I'm planning to use a resonant linked dipole with the QDX when out
By Wayne KB4DSF · #108764 ·
Re: QRP antenna tuner?
Although in the UK, Kanga Products make the excellent pocket transmatch as a kit but also as a complete built and tested unit. Not sure if postage to the US is viable, but worth
By Daimon Tilley · #108763 ·
Re: QMX - smoke - another C107/Q108 failure
What is the mechanism that reduces the voltage on LIN_REG_IN during that half-way state from the supply voltage to 3.3V? ?It seems to me that the supply voltage passes through Q103 & Q105 (on the 5V
By Jonathan Burchmore · #108762 ·
Re: BS170 Fail
Hi Wayne, An absorptive bridge uses resistors and a voltage measurement to measure SWR.? The way that it does this puts the worst SWR the TX sees at 2:1.? You need to switch the bridge out once the
By Evan Hand · #108761 ·
Re: BS170 Fail
Wow! Thank you all for the responses. I'm thinking I'm going to give the TN0606 a try, and use some thermal grease. Thanks for that hint. I'm about to expose my real lack of knowledge by asking what
By Wayne KB4DSF · #108760 ·
Re: QMX - smoke - another C107/Q108 failure
It seems to be in a half way state at that time, The linear supply FET Q102 is on and so is Q110 which provides a load for the SMPS. But Q111 is also on so the power can come from the linear or t
By Chris, G5CTH · #108759 ·
Re: QMX working FB then shorted out. Ideas?
I suppose it depends on how they failed... I have (had) mine in sockets, so they're relatively easy to remove for troubleshooting. Good Luck! 73, Paul -- AI7JR
By Paul - AI7JR · #108758 ·
Re: WSJT-X with QMX
This group may be able to help. Wsjt-x-improved-community mailing list Wsjt-x-improved-community@... https://lists.sourceforge.net/lists/listinfo/wsjt-x-improved-community They were
By Chris, G5CTH · #108757 ·
Re: QMX - smoke - another C107/Q108 failure
I don't think LIN_REG_EN is turning "off" at 80ms--I think what we're seeing is the handoff from the initial supply voltage (through PWR_ON?) to the 3.3v signal from the processor PD7 once it has
By Jonathan Burchmore · #108756 ·
Re: WSJT-X with QMX
Was successful today with WS (See picture) but not without hassle I believe caused by Windows OS and not the radio. About the time I think I have the turn on/connect/ enter sequence down pat something
By Karl · #108755 ·
Re: No receive QMX
I used the ?QMX yesterday in what I call hybrid mode QMX TX, Web sdr for Rx works a treat if remaining on one frequency. ?Checked everything as far as I could but can't find any errors, even removed
By Paul Harrison · #108754 ·
Re: QMX - smoke - another C107/Q108 failure
No, it did not appear to do so. ?If you look at my original scope traces you can see that VCC starts right around 1V because I had been turning the QMX on and off as I adjusted the scope trying to
By Jonathan Burchmore · #108753 ·
Re: QMX working FB then shorted out. Ideas?
Found the part ok. $0.23 and shipping $7. <sigh> Have to try to guess what other parts I many need to justify the shipping. 73, Cliff, AE5ZA
By Cliff · #108752 ·
Re: QMX: Kit build trouble, a short between A & B for Step 17 of Section 2.9
According to the assembly manual it says "Finally, there should be NO connection between A and B. Hold one probe on any A point and the other probe on a B point. That should read infinite resistance
By Chris AG6CK · #108749 ·
Re: QMX working FB then shorted out. Ideas?
Well, Steven I owe you on this one. You called it right to the component. The short was on the 5V rail and the component was D108. That is sure a tiny little diode. Going to be fun to put a new one
By Cliff · #108748 ·
Re: QMX - smoke - another C107/Q108 failure
It's possible I measured the wrong thing? ?I measured it from what I thought was pin 3 of the 3v3 SMPS board. ?The middle pin on the top. Jonathan KN6LFB
By Jonathan Burchmore · #108747 ·
Re: BS170 Fail
Hi Wayne, To answer question 3… there is a better transistor for replacing the BS170’s - TN0606. The data sheet can be found
By Tony Scaminaci · #108746 ·
Re: QMX - smoke - another C107/Q108 failure
It looks like about 38 seconds or so, if I'm measuring this right. Jonathan KN6LFB
By Jonathan Burchmore · #108744 ·
Re: QMX - smoke - another C107/Q108 failure
Here's a tighter view: And zoomed in on the linear regulator portion. ?Vertical scale in both is 500mV/division with a -1.5V offset. Here's a similar trace with channel two showing LIN_REG_EN.
By Jonathan Burchmore · #108743 ·
Re: QMX substitute for Q103
I don't see why it should not work with the AOD21357. Specs are very similar to the AOD403 and both are well over dimensioned for this purpose. I would try it if I were in your shoes. Experience is
By aa0jr Jakob <aa0jr@...> · #108741 ·