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Minor typo. On page 5, Step 1. Currently says cut 25mm of wire...should be 25cm. Roger 8P6RX ?Get BlueMail for Android ?

Oh yeah… the downside of being hosted on a shared server. I remember this biting me years ago and having to move to a new web hosting service. Seems that some of your brethren are compromising

Thank you Hans. After reading the doc I take it that the improvement for low band units is not significant enough to warrant replacing the original type of transformer, yes? 73, Cliff, AE5ZA

The majority of the heat is conducted by the leads, mostly by whichever lead (usually the center) has the transistor die mounted on it.

If terminated by 50Ω, a 20dB pad makes a reasonably precise 10:1 voltage divider.? To do this I use a "50Ω feedthru termination" between the pad and 'scope input.? You can check/calibrate it with

Hi John, I am sure that IC5 has failed.? This is common when the BS170s fail.? Continuing to try to run the QDX could cause IC2 to fail and possibly other issues.? I would remove IC5 and verify

Kees, You are correct. PB4 is vulnerable at the same time and for the same reasons as PD7. Further, as an analog input to an ADC, it is never given 5V tolerance, so its vulnerability extends

Your suggested alternative for tapping input is also a good solution, but there's absolutely nothing wrong with the method I proposed of using the high impedance probe and a cable tee below 50Mhz.

John VK7JB, I have TWO QDXs that both suffered the same fate as yours -- working perfectly, then mid-transmission death resulting in high current on receive (400 mA) and a hot IC2.? I removed the

JZ, Following your logic, another point for a 3.6V Zener would be PB4 on the Micro for powering OFF. 73 Kees K5BCQ

Acknowledged - thanks. -- - 73 de Andy -

OK, Kees...got that...JZ

JZ, The problem I was trying to address was to allow the Micro to run its FW ASAP. As far as the LIN_REG_EN voltage, I take it you are concerned about the very small amount of current through the

Hi all Many thanks to Ross EX0AA for his transformer designs, the 3:3 ratio (9V operation) WTST (Weird Twisted Sisters Transformer) and 3:2 ratio (12V operation) RWTST (Really Weird Twisted Sisters

Colin thus spake: Hans, I used to send all my email from a server I owned. There was a period where it wasn’t getting through. I was only sending private correspondence and no business emails at

Good points, all! Paul

Kees, That would not solve the fundamental problem, which is LIN_REG_EN can pull the MCU pin too high. A better solution might be a 3.6V Zener from LIN_REG_EN to ground. The V(absmax) spec could

Hans, we can set up echoing internet emails with JS8Call mailboxes :-) Would also be available to communicate as a group when war breaks out. 73, Joe W2JEJ wrote:

Relative to power sequencing: would there be any advantage to using the PWR_ON switch to route V_IN to the "+12V" connection on Q102 (only) for bringing 78M33 3.3V up first/fast to the Micro. The

Hans, I see you are blacklisted by two of the lists. You can check you status here: https://mxtoolbox.com/SuperTool.aspx?action=blacklist%3aqrp-labs.com&run=toolpage wrote: