Long time, no post

It has apparently been something like 2.5 years since I've done anything here.  I wasn't having any time to work on electronics, and I really needed to do something non-technical outside of work anyway, so I put away my gear for a while.  But my hobby interests seem to be cyclical, and I'm firing up the iron again.

This past week I've done a few things.  First, I cleared the desk and got the gear back out.  Then I've been reading over the blog to try to remember where I got to the last time I worked on anything.

I got out my NS-40 and powered it up.  Still works great.  So I got out my version of the NS-40 circuit and did some measurements on it for a bit.  But at some point I keyed it and there was a spark, and it doesn't seem to be working anymore.  Whoops.

Then a few nights later I got out another Si5351 and wired it up with my Arduino (I blew the last Si5351 at some point).  I downloaded the sample Adafruit library onto it except changing clk0 to put out something near 7Mhz (I think it is 6.8 something, but the clock designer software doesn't run on Mac and I'm being lazy).  Looked at that output into the dummy load a bit (through the LPF network).

Today I tried the 74AC240 experiment again.  I'm again trying to wire the outputs in parallel to drive more.  Taking my cues from this page (the TTL version).  But going slowly, I tried just driving a single input and going into a high load (20k or something).  Seemed to work on the breadboard, but crazy ugly.  So moved it to a perf board.  I tested all my connections as I went, and found that the 1M to ground link was showing 25 ohms.  Super confused.  Finally moved from input 0 to input 1, and it seemed to work.  So maybe I accidentally blew up something on this 74AC240 the last time I was playing with it.

Next time I'm going to try to parallel the remaining lines (skipping input 0, as it seems sad now) and seeing what that looks like into the dummy load.

As an aside, I'm going to look into ordering some proper mosfet drivers.  The '240 experiment was kind of to see about using it to drive an IRF510, but I think even if I get the power out, I'd need to put a transformer between it and the IRF510 to get the voltage I want.  I *think* I can get some gate drivers that would work at 40m for not much, and that would be far easier and probably more predictable that what I've been playing with so far.