ad9850 vfo

I picked up one of the cheap ad9850 modules from China and made a new vfo. I modified this code from ak2b to use the ad9850 instead of the si5351. To see my si5351 vfo, click here. As you can see from the waveform and the frequency counter at the bottom, this little module seems very accurate. Since it also produces a square wave output, I may try to build a little function generator.

diy dummy load

Being a new ham, I’m starting to find myself in need of a dummy load. I’ve decided to build one of the fairly well-known paint can dummy loads. You can see some examples here, here, and here. The basic construction of the dummy load is twenty 1k ohm metal film resistors in parallel, sunk into an oil filled container for cooling. Using 3 watt resistors, it should be able to take 60 watts easily and with the oil cooling it should be able to handle up to 100 watts for short periods of time.

diy solder fume extractor

I’ve been meaning to build a small solder fume extractor for a while and I finally got around to it this weekend. It is a pretty straight-forward project with a small parts list. You will need: an enclosure a computer fan a switch a dc jack 12v dc wall wart activated charcoal filter  For the enclosure, I used a small food container. You can see in the picture above where I marked the holes to mount the fan.

backups with obnam

After playing around with my backup appliance from this post, I ended up switching the backup software from rsnapshot to obnam. Obnam seems to work better and have more features than rsnapshot, like deduplication, encryption, etc. The only problems that I have had with Obnam are slow backups, but I can live with that. I’ve replaced rsnapshot with this command: obnam backup -r /mnt/backups sftp://awsh@{my server}:/home \ --client-name=awsh_backup_client --log-level=debug \ --log=/var/log/obnam.

encrypted backup appliance with raspberry pi and rsnapshot

*** I actually ended up replacing rsnapshot with obnam as detailed in this post. *** Today, I decided to switch up my backup routine. Before I was using a mix of bash and python scripts to backup different machines, but I wanted to set up a single appliance that could take care of all of my servers and keep backups in a centralized, encrypted location. What I ended up with is a raspberry pi with an encrypted 4TB usb drive.

rtl-sdr upconverter

I’ve been productive this memorial day weekend. I ran across a great deal on a digital oscilloscope on Friday. It’s an Aktakom ADS-2061M that was brand new in the box and I got it for the price of a raspberry pi.  With that, I was able to put together an upconverter for my rtl-sdr dongle. I used a NE612 mixer with an si5351 oscillator running at 112.5MHz. The arduino is driving the si5351 breakout board.