Using old walkies with Li-ion batteries

Like most hams, I have some old equipment. To be precise I own an FT-911 walkie, who uses from Ni-Cd batteries. The original battery died many years ago. Because nowadays it is difficult to get Ni-Cd batteries, I rebuild the pack using Ni-MH batteries instead.

No matter what brand of batteries you choose, or what kind of charger you use with them: they will be dead in just few months. I'm really concerned about the quality of Ni-MH batteries today. Because I really got tired of replace the battery cells, I looked for a different kind of battery. What about Li-ion batteries?

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!