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
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Wayne KB4DSF
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#108764
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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
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Daimon Tilley
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#108763
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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
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Jonathan Burchmore
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#108762
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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
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Evan Hand
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#108761
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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
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Wayne KB4DSF
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#108760
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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
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Chris, G5CTH
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#108759
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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
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Paul - AI7JR
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#108758
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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
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Chris, G5CTH
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#108757
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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
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Jonathan Burchmore
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#108756
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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
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Karl
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#108755
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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
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Paul Harrison
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#108754
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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
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Jonathan Burchmore
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#108753
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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
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Cliff
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#108752
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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
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Chris AG6CK
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#108749
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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
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Cliff
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#108748
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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
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Jonathan Burchmore
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#108747
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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
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Tony Scaminaci
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#108746
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Re: QMX - smoke - another C107/Q108 failure
It looks like about 38 seconds or so, if I'm measuring this right.
Jonathan KN6LFB
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Jonathan Burchmore
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#108744
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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.
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Jonathan Burchmore
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#108743
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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
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aa0jr Jakob <aa0jr@...>
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#108741
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