HF Receiver Testing – Zero IF Direct Conversion_b

Introduction In the previous post (Ref.1) I examined the signal flow through the RPiZonia Zero IF Direct Conversion Receiver by examining the Block & Level testing diagram. Figure 1 shows the schematic diagram. Figure 2 shows the Block & Level testing diagram. Reception SW Station 11.930MHz In order to receive a shortwave station on 11.930MHz,… Continue reading HF Receiver Testing – Zero IF Direct Conversion_b

HF Receiver Testing – Zero IF Direct Conversion_a

Introduction Several years ago I developed a Zero IF Direct Conversion HF receiver (Ref.1) to be used as a lab component of my HF Telecommunications course (Ref.2). The idea was to learn HF theory by Scicos simulation, electronic circuit design (schematic capture, pcb design, LTspice simulation, working with smd) and testing with a scope and… Continue reading HF Receiver Testing – Zero IF Direct Conversion_a

OpenPlotter – RPi4 – USBpwr

Previously all my work on OpenPlotter was done on an RPi3B+ installed in a PI-TOP3 development Laptop that featured a screen, keyboard, and proto board connected to the GPIO (Ref.1-Ref.10). I started with the basic installation, OpenCPN with GPS, OpenCPN with GPS & AIS, Marine Weather on GQRX, Sensors for Temp/Pres/Pitch/Heel/Compass Bearing and GRIB weather… Continue reading OpenPlotter – RPi4 – USBpwr

RTL-SDR – V1/2/3 – USBpwr

Introduction In many applications, where ac power is not available, equipment must be operated off battery/solar systems. In these case, knowing your power requirements are critical. Recently, small inline USB power meters have become available and they can give you an immediate answer to this question (Ref.1). RTL-SDR – V1/2/3 Power Measurements I did a… Continue reading RTL-SDR – V1/2/3 – USBpwr