SamKnows is a global Broadband Quality Monitoring service. They are funded by a number of national regulatory bodies, including the FCC and OfCom, and are to all intents unaffiliated.
A while ago, while browsing Ham Radio channels on Youtube, I came across an interesting project. Chris, M0NKA, an obviously talented hardware designer had designed a QRP Software Defined Radio (SDR) based on the STM32F407 from STMicroelectronics.
Among other great features of the Raspberry Pi is the General Purpose Input Output array (GPIO). This is an array of pins that can be programmed to behave as pretty much any I/O type that can be represented digitally. The pins can be switched on or off to represent binary 1s and 0s and controlled so as to emulate any communication protocol that uses bits (I2C, SPI, RS232 etc. etc.). However, as a first attempt at working with GPIO, I took a recommendation from Steve EI5DD and wrote a program that will key a transceiver and generate morse code.
Following a suggestion by Galway VHF Group mamber Steve, EI5DD, I thought I would give SSTV a shot. It's not a mode I have any experience with, apart from hearing the transmissions at 14.230MHz when I tune around. Steve mentioned a cross-platform SSTV program QSSTV, which seems to run well on a Pi 2, so that's what I decided to use.
I recently upgraded my shack to an ICOM IC7300, which in the EU specification includes the 4 meter / 70MHz band. I do not have a vertical for 4m, or space for one right now, but had read about others using a small matching unit to provide the necessary match using the Diamond V2000, or Watson W2000, as my version is badged.
At the Mayo Amateur Radio Rally a couple of years ago, a NI ham, Tom Herbison, MI0IOU was selling an interesting kit for the Raspberry Pi. It combined an Analogue Devices Clock Generator (AD9850) and an RF power meter (AD8307) to give a programmable sweep generator & detector... commonly known as a Wobbulator. I bought one and had anenjoyable afternoon not long afterward building it. It was a relatively easy build, and I got some use out of it tuning some Band Pass Filters I had built for use on multi-station portable ops.
I have been playing with Software Defined Radio for a number of years, but recently advances in high-speed sampling has put relatively high quality, extremely high frequency SDR within reach of everyone. A few years ago Eric Fry reverse-engineered the communications from a Digital TV USB Dongle to see that it transmitted raw samples.
Now that the weather is improving, I decided to dust off the /P kit and ensure that all was working will in anticipation of getting some outdoor operation. I had bought a lightweight dual-band beam for this purpose so decided to put it on a pole and see how it performed.
The FT817 from Yaesu is still the most featured portable radio available. The Elecraft KX3 might have better HF performance, but for sheer spectrum coverage, it doesn't come close... unless you spend a few hundred more Euros for the 2W output 2m or 4m transverter. You will definitely have a world class radio, but it still won't do UHF, and would cost something between twice and three times what an FT817 would.