VK4ZXI

BladeRF, the XB-200 transverter and HF TRX; it's been there all the time! The BladeRF and now its XB-200 transverter are very neat pieces of gear. Now the big "but" or "however". Many people have been wanting to use the BladeRF on HF and were waiting for the transverter to be delivered in anticipation of it covering HF. However, the original range of the transverter was 30 to 300 MHz, with no apparent coverage. When the final design and photos were released, coverage was 60 kHz to 300 MHz, which no doubt pleased many people. I went though the schematics trying to find the modifications to cover HF, but they were not apparent, a point I raised in the Nuand forum. I received a reply from Nuand to say that the HF access was not very obvious and went to the ADC/DAC. This mystified me for a few days until it finally clicked on how HF is done, which is exactly what they way they said. However HF TRX is virtually independent of the transverter and could have been...

Red Pitaya: arrived and working My Red Pitaya has arrived and was working with a minimum of fuss. Simply type in the device's unique MAC address on the connect page http://discovery.redpitaya.com/  and hit connect. The instrument functions are web applications. Just click which instrument you want and it comes up in a web page. I was curious how they could get it to work on any computer, tablet or operating system, but the web access is the answer. I am not sure what consequences that has for performance, but it works and it is still early days. The Red Pipaya connected to give some idea of size. It gets pretty hot, maybe too hot for a warm climate like northern Australia; we shall see. The device is working as an oscilloscope and signal generator, with an output connected to an input. A sine wave at 20 MHz. Many of the adjustments are manual and take a bit of getting used to. However, it works. Not the cleanest sine wave; not sure if it is the signal generator or os...

New TRX- IC-7100, a look inside I have just purchased a new IC-7100 to replace the FT-857 and FT-897 all-band, all-mode TRX I had. The Yaesu TRX were good radios, but dated designs. The IC-7100 on the other hand is a very modern design and radical form with a separate touch screen controller. The IC7100 is a similar but different design to other modern Icom TRX such as the IC-7410 and IC-9100. All are software-defined radios, with all modulation and demodulation done in software/firmware in the DSP and codec chips. All other signal processing is also done in software. Analogue devices are used for amplifiers and mixers. Band, low-pass and roofing filtering is done with discrete components, but all signal filtering is done by the DSP. I will say more of the design, but for the moment I have some photos of the main unit's PCBs. The mechanical design is simple. The top board is the frontend for both Rx and Tx with most components of one side of the board mainly bec...