When I got my hands on a used NanoVNA H4 I couldn't resist looking inside to see if it was using shielding for the RF components. Turned out it did so I bought the right one. But one thing I noticed was the component silkscreen for a micro SD-card slot without the slot it self and because it still contained the original software which didn't mention anything about saving images to SD cards, I didn't do anything with it.  

Until now . . . (continue reading)

Got my QCXmini kit from QRPLabs and finished it. So I added a complete building report (incl designs for the tilt-feet) on this page. 

A few owners of the new NanoVNA H4 have requested me if I could re-design the PCB so male SMA edge connectors can be used to directly connect the adapter PCB to the NanoVNA H4.  For a while I holded it off, but recently I got my hands on a used NanoVNA H4 which I'm very happy with because of the bigger screen (yes my eyes aren't getting better). I started to use the H4 and wanted a dedicated adapter for it. So I measured  my NanoVNA H4 and it has a distance of  39.5mm and comments from other OM's indicate that it's quite constant +- 0.1mm. 

So I made a copy of the original design and changed the board layout to fit our needs. 

continue reading

I have added 2 pages to the Tools and parts section of this website. 
A rebuild of the K7QO noise generator and a new Dual tone audio oscillator

For RF applications, one of my favorite ways to build is the ManhattanStyle  and I have build a lot of these circuits in mint tins.  One thing I'm always  struggling with are the  9V batteries holders and on/off switches. So I 3D designed and printed this 9V battery compartment with room for 1 or 2 common cheap PCB push button on/off switches (they come in lock and momentary versions).  continue reading . . . 

Recently I found a page which described Roy, W7EL, Lewallens Simple & Accurate Directional Wattmeter as it was published in 2/90 QST.  Searching for more information I noticed that W1REX - QRPme also has a updated version of this Simple & Accurate Directional Wattmeter. 

continue reading . . . .