An RTL-SDR receiver & Ham It Up RF upconverter arrived, with the intent of poking at LF signals. The upconverter circuit board also contains a mostly populated RF noise source:
Being a sucker for noise sources, I spent some time pondering the circuitry.
The as-built board has a 0 Ω jumper instead of the 6 dB pad along the upper right edge:
The previous version had a pi bandpass filter in place of the pad and you could certainly repopulate it with two caps and a teeny inductor if you so desired.
I added the SMA connector, which isn’t quite identical to the IF output connector above it:
That will require a new hole in the end plate that I’ll get around to shortly. It also needs an external switch connected to the Enable jumper, but that’s in the nature of fine tuning.
I’m awaiting a handful of adapters & cables from halfway around the planet…
The Smell of Molten Projects in the Morning 
Comments
4 responses to “Ham It Up Noise Source”
I don’t see a lot of those through-hole SMA connectors these days, usually I come across the end-launch surface mount ones where the board fits between the ground prongs. Did you just happen to have that connector on hand?
It’s amazing what you can find on eBay these days; I’ve arranged to have a bunch of RF hardware tucked into the nooks & crannies of various shipping containers. [grin]
Earlier H-I-U boards used those fragile edge-mount SMAs; sometimes the old ways are better…
[…] new SMA noise output jack sits in the front left, with the white “noise on” LED just left of the […]
[…] strip across the top contains ten U.FL connectors, a few of which might make their way onto the Ham It Up board. They cost a grand total of $2.09 (not the $12.00 shown on the label) delivered halfway around […]