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The QRPGuys SWR indicator uses an absorptive bridge in its design. I use it with my QMX. My problem is that I tend to band hop a lot and I often forget to switch it in for tuning. No problems yet, but

Evan's answer is correct but misleading because this is not the sort of SWR bridge that QMX has. QMX has a Stockton bridge and all it does is measure the forward and reflected power (or voltage?), By

I think there's some good argument (personal enrichment not least among them!) for using discrete parts. I like it, Hans! The thing I found difficult was that /both/ PS boards must be present (and

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Hi Wayne, To answer question 3… there is a better transistor for replacing the BS170’s - TN0606. The data sheet can be found