Using the Eyal Gal 10GHz module in a ham radio transverter

The core of my transverter project is a 10 GHz Eyal Gal module adquired in eBay the last year. These units have a receiver converter and a transmit power amplifier in the same enclosure.

Because the design frequency of the module is 10.4 to 11.7 GHz, it works unmodified at 10368 MHz, which is a clear advantage for use at ham radio.

There is not too much information about these modules except the info published by G8CUB here and here, this post from M0DTS and this datasheet. It is convenient to read all these documents before continue reading this post.

Setting the output power in Yaesu FT-911

Recently I have been using my Yaesu FT-911 as signal generator to test a 10GHz transverter's local oscillator multiplier stage (1242 x 8 = 9936 MHz). Everything worked fine, but the readings I had were not consistent. The output power was lower than expected.

When supplied at 13.8 volts, high output power should be 1W, but I was measuring around 550mW. Clearly something was wrong. Many time ago, when I purchased the walkie, I did a quick readjustment using an attenuator and a spectrum analyzer. Spectrum analyzers are fine to see spurs or relationships between carrier and armonics but they are not good as absolute power meters, specially if you are using them at the top of their dynamic range, this is with insufficient attenuation between.

Repairing a Telecom AV-830 switching power supply (or maybe upgrading it)

I have an auxiliary Telecom AV-830 switching power supply I use from time to time. Recently while testing a circuit with it, the power supply explodes. The internal fuse was disintegrated and the main ICP was activated. That usually means something very bad is happening with the power supply.

A 10MHz TXCO master oscillator

The heart of any transverter system is the local oscillator. In practice, a transverter is as good as its local oscillator is. For my transverter project I choose a Toyocom TCO-291L2 oscillator I rescued from a UMTS board I have from surplus.

After spending a lot of evenings looking for its datasheet, I could not find it. I found the datasheet from other TCO-291 oscillators, but nothing from the TCO-291L2. Maybe it is a custom device, o maybe it is discontinued.

New CNAF in Spain.

Today, a new CNAF have been publised in Spain. CNAF stands for Cuadro Nacional de Atribución de Frecuencias, literally National Table of Frequency Allocations. In Spain this is Law, and a new CNAF is usually the prelude of new ham radio regulations.

Looking for the Square Law region (III)

... and all I can say is I found it!

Last weekend I assisted to a small ham radio flea market surprisingly with a lot of microwave hardware. Thanks to Andrés EB4FJV, I was able to get a DC to 18GHz Narda crystal detector. My idea was to use it as a relative measurement device, just to peak circuits at maximun output.

DRSB-01 Geiger counter failure

My DRSB-01 ( ДРСБ-01 ) geiger counter has gone mad. Far from any source it gives up to some counts per second, when the normal rate for it in my home is around 20 counts per minute.

Once opened was easy to spot the failure: The high voltage applied to the tube was around 800 volts. The normal working voltage of the SBM-20 tube is around 400 volts, so 800 volts produces self-triggering, and therefore, the extra counts.