Geminids 2013 with Baudmeteors

Last weekend I used Baudmeteors to study the Geminids meteor shower using the Graves radar. I left the computer logging data for more than 120 hours trying to catch the shower peak. And I did it:

Shielding the UT-81B oscilloscope

About three years ago I brought an UT-81B multimeter/oscilloscope. It is not a high range oscilloscope, it is more like a low range / "toy" oscilloscope but it has worked very well for me, making a great job solving problems with my Geiger counters and gamma spectrometers.

But it had a small and somewhat annoying problem: While in stand by, a pulsating signal appeared on the screen.

FM passive radars as alternatives to Graves

Two weeks ago, on November 13, I left my computer logging meteors on Graves' frequency with the help of Baudmeteors. My goal was to catch the Leonids shower. But on November 15, around 16:40 UTC I detected one meteor and then, only silence for the next two days. Graves was turned off.

You don't realize how dependent the radio meteor detection is from Graves until you lost it. Around 20 UTC I realized there was no problem with my radio or just a very low meteor count. Graves were really off!

Baudmeteors: Capturing meteors with Baudline

I already knew Baudline. I used it some years ago as a simple FFT spectrum display but I didn't use it until last summer, when Iban, EB3FRN sent me a little script to automate meteor capture using Baudline. It turned out Baudline was much more than a simple spectrum analyzer display. Baudline turns out to be a powerful signal analyzer and quickly it becomes one of the most used programs in my computer.

Impressive "dual band" feed

This weekend I've reviewing some photos taken last summer, and I found this interesting photo from an interesting dual band feed for parabolic dishes:

HamGPS in action!

Yesterday I received a message from Eddie (ZS6BNE), who pointed me to a great video about RaDAR (Rapid Deployment Amateur Radio) operation. You can briefly see HamGPS in action, around 2:20.

RaDAR Promotional Video from Edwill Leighton (ZS6BNE) on Vimeo.

According to Eddie's blog, HamGPS is a quick way to get very precise positions that can be easily send to another hams using 10 digits grid world wide locators.

Thanks for sharing, Eddie!

Pipe cap filters for 10GHz

The most common problem in a transverter system is local oscillator leakage, this is the local oscillator signal get through the TX mixer to the power amplifier chain, becoming present at the antenna connector at some level. LO leakage is usually a sign of poor design, but it can occurs also by defective or wrong shielding or even by a metallic enclosure box.

In my case the problem was the metallic enclosure used for the transverter. With the cover removed everything was fine but once the cover was put in its place, the local oscillator was present at the output at nearly 5mW of power: Just unacceptable.