Sunday, September 24, 2017

Repairing an Anritsu MS2711A handheld spectrum analyzer

One night, I was searching eBay with no especial interest when I found something interesting, a non working Anritsu MS2711A spectrum analyzer. The photos shown a turned on analyzer, and some signals (noise) appeared in the LCD. The LCD had some dead lines at the bottom, but nothing serious.

A small size spectrum analyzer is very tempting. I have another two full-size spectrum analyzers but they are so big and my space so limited I rarely use them. These small units are somewhat very limited compared to a real spectrum analyzer, but I was pretty sure I would use it much more often than the two units I already have.

After a few minutes, I decided to buy it.

Friday, September 8, 2017

Repairing the OM345 hybrid module

Recently I had to repair a Marconi 2022E signal generator. It's a nice unit, relatively small, and well suited for amateur use. Talking about repairing the old Marconi instrumentation is talking about the Phillips OM345 hybrid modules. Why? Because they has a really high failure rate and old Marconi equipment make extensive use of these modules.

Sunday, July 16, 2017

Considerations about the Hiland Adjustable DC Regulated Power Supply Kit‎

My "lab" power supply was a homemade one I made/upgrade some years ago. It was constructed around a LM350K TO-3 regulator and worked very well. But I really missed one function: adjustable current limit.

The LM350K regulator has a fixed current limit around 2-3 amps, but usually that is just too much current for a prototype. Many times, when something went wrong, one or more components went burnt.

Monday, May 29, 2017

Shifting to Linux

Some time ago I received a notification via Twitter about someone who installed XP on his notebook after reading my article about Linux I wrote some years ago. I think the tweet is ironical, but that doesn't matter.

The fact is I didn't remember I wrote that article, but actually I'm using Linux full time in my desktop computer. How can it be possible? How someone who ranted about Linux on the desktop ended using Linux full time?

Friday, May 12, 2017

About the CTS OCXO Board

After some time working 10 GHz with a TCXO based local oscillator I decided to upgrade it to a OCXO because stability was not as good as I would expect. It was ok for a short QSO but after some time I must search in frequency to the other station again. It was not very practical.

I decided to try a CTS OCXO Board from ZL2BKC. It is a small board with a brand new 10 MHz OCXO made to complement the ZLPLL board, and it is available in kit form for just $20: a bargain!

Sunday, April 10, 2016

Determining the radiant of a meteor using Graves radar (III): the details

In my previous post I explained what we did and what results we got. In this post I'll show you the technical details behind the experiment, with some hints and tips in the case you want to replicate it. As a guide, I'll solve a meteor step by step, from the wav file to the radiant, and then, the final orbit around the sun.

Friday, April 8, 2016

Determining the radiant of a meteor using Graves radar (II)

One year ago, I published my experiences about determining the radiant of a meteor using Graves radar. If you read it (I hope you really did it) a question arises immediately: What about three receivers? Fortunately David, amateur astronomer and ham radio operator also known as EA1FAQ joined the team so we could answer this question.

Figure 1: Transmitter and receivers location

We had some doubts. Could the same meteor head echo be received simultaneously by three different stations? some calculations and simulations were made with many interesting results.