EME and Weak signal communication
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IQ+ Pro
10 years ago the first IQ + radio was produced and then introduced in HB9Q, where it became the de facto standard radio to combat faraday rotation in the 144 and 432 Mhz bands. Several models and variants have been produced, 3 different revisions where in a small steps the characteristics were improved, reducing the phase noise of the oscillator, improving the noise distribution in the different amplification stages and increasing the dynamic range. Increasing performance in a system that already has a high degree of performance is not an easy thing, it is like aiming at a moving target with a series of interconnected parameters, when we improve one part we get worse in the other and this forces us to search always the optimal balance.

For years the limiting factor for SDR ZERO IF has been the Analog-Digital conversion. For this we have used the audio cards, unfortunately these devices were designed for music and voice in mind but never thinking in an SDR application for weak signals as in EME. After a long journey I introduced the UADC4, the first universal AD converter designed and optimized to work with an SDR like the IQ +. This allowed the noise floor to drop from -142dBc / Hz (in 1Khz BW) to -162.8 dBc / Hz (in 1KHz BW), increasing the dynamic range, reducing the amount of spurs and birdies and making the overall system more Immune to interference.

In this sense, the IQ + Pro is the combination of two technologies in a single device where the AD conversion is performed by an identical circuit like the UADC4 but associated with an IQ mixer with much more performance than the predecessor IQ +. The new IQ + Pro has already seen 2 prototypes and I am working on the third, it is a very complex unit with a 4 layer PCB and many special components. The original plans were to produce the first units in mid 2020 but the global Covid-19 crisis has disrupted various electronic supply chains and prototypes are becoming more difficult to implement.

Soon I will publish technical information regarding the architecture of the IQ + Pro.

Stay tune
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