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Fred's Blog about Ham Radio, Python, Unix and more...

APRS Telemetry

I wrote a little python program to send my iGate telemetry through APRS. The metrics include the temperature of the Raspberry-Pi, the load average, the amount of free memory, and network traffic. Sending the iGate metrics through APRS allows me to use the graph tools offered by aprs.fi or …


Common mode current and chokes

Tech day in Sacramento This Friday, I was invited to Sacramento to give my presentation on common mode current, what it is, and how to block or prevent it using common mode chokes. Once a month, Jeff (AK6OK) and Craig (N6YUV) organize a meetup they call ham tech day. A …


Measuring Toroid Attenuation

I needed to remove some RF noise from an air filter in the next room. When the fan turns on, the background noise raises my radio S meter by 2 S units. Like most of you, I tend to collect ferrite cores from random places. Unfortunately, the ferrite cores I …


D-Star with an Icom ID-4100

A couple of weeks ago I got a new D-Star mobile radio. The radio is an Icom ID-4100, VHF/UHV. According to Icom, this rig is a D-Star1 entry-level radio. The ID-4100 has the same features as the ID-5100, with a smaller screen and only one VFO. Clear display …


High Altitude Weather Balloon.

A few months ago, I watched YouTube videos about ham radio operators launching high altitude balloons. They carry a tracking device and a camera to take beautiful pictures of Earth. The tracking device is used to follow the airship on a map but also to retrieve the payload. Ham radio …


Battery board with protection cut-off

A couple of months ago I designed a convenient Battery Monitor board with a voltmeter, one Andeson PowerPole connector as well as a USB power connector. This board is suitable to turn any 7Ah, 9Ah SLA or Lithium battery into a convenient power source for indoor or portable operation. For …


Logging on MacLoggerDX with Fldigi

One of my favorite activities on the radio is making contacts using digital modes. I'm not talking about FT8. I mean real conversations using modes such as Olivia, Contestia, Domino, PSK31, etc. To make these contacts I use a software called Fldigi. I think I have made at least one …


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