Author: Razvan

Baofeng DMR6X2 – dual band DMR handheld, 7W output

Baofeng, your favorite Chinese manufacturer is at it again. Their next product is called the DMR6X2 and as you might guess, it’s a DMR radio. A handheld, VHF/UHF, Tier I & II DMR radio that has up to 7W output to be exact. You don’t need to have a really sharp eye to notice that the radio in the picture is actually an Anytone AT-D868UV; it seems like rebranding it as a Baofeng DMR6X2 might make sense, especially if this would mean adjusting the price downwards, maybe to compete with the Radioddity GD-77 and the like. Some of the...

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Yaesu FT-757GX – fixing some common faults

I recently got a Yaesu FT-757GX to use as a backup radio for the shack. The previous owner said it has no RX audio on any other modes except CW, but the TX was fine and the S-Meter was moving on all modes. This got me thinking there is just a problem with audio switching and by looking at the schematic I knew where to start. When I got the radio, opened it up and started to diagnose the known issue, I discovered many more. As I came to find out these are quite typical for the Yaesu FT-757GX,...

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Si5351 output waveforms

I finally managed to have myself some shack time this weekend and one of the curiosities I had was to check the output waveform of the Silicon Labs Si5351 I2C programmable VCXO. The chip is quite popular among homebrewers thanks to its low price, ease of use, the fact that it generates 3 independent outputs across a very wide bandwidth (8kHz to 160MHz) and that it offers lower phase noise than the cheap & cheerful AD9850/1 DDS modules.   Adafruit Si5351 module By the way, there are also some versions of the Si5351 that have 8 independent outputs instead...

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RedPitaya expands line-up with 7 StemLab models

Red Pitaya, the 21st century alternative to laboratory test instrumentation, have just replaced their single product with 7 new models called STEMlab. The original Red Pitaya is a powerful piece of hardware that can act as a dual-channel oscilloscope or spectrum analyser, signal generator,  8-channel logic analyser, LCR meter, vector network analyser and much more. It has no problem working as a dual-RX dual-TX DDC/DUC HF+6m transceiver and there is even a project for a full featured final product in the works, called the Red Pitaya Hamlab. It can do all these thanks to the fast 14-bit 125Msps dual-ADC,...

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Onion Omega2 – $5 WiFi Linux computer

The Onion Omega2 is a miniature Linux computer with integrated storage and WiFi connectivity. It runs on Linux so it supports many programming languages such as C++, Python, PHP, nodeJS etc, plus there are apps you can install for different purposes. The base Omega2 model costs just US$ 5 and comes with a 580MHz CPU, 64MB RAM, 16MB storage, b/g/n WiFi, 15 GPIO ports, 2x PWM, 2xUART pins and I2C, SPI and I2S interfaces. There is also an Omega2 Plus version that is currently US$ 9 and has 128MB RAM, 32MB onboard storage and an MicroSD slot, which might...

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Baofeng UV-50X3 – new mobile radio

Baofeng just launched the UV-50X3 triband mobile radio and it looks like a jab, cross and left hook to the established japanese manufacturers who were caught dreaming about DMR, C4FM, D-STAR and other leprechauns. Yes, the chinese manufacturers aren’t creative, but they are really good at copying stuff and manufacturing it for a fraction of the price, so the resemblance to some japanese models shouldn’t surprise you. Or maybe the Yaesu FTM-350AR ? Kenwood TM-d710 looks a bit similar, don’t you think ?     The tri-band FM Baofeng UV-50X3 can transmit in 3 amateur radio bands (2m and...

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Red Pitaya Hamlab – HF/6m 10W SDR transceiver and much more

Red Pitaya Hamlab has just been announced at Friedrichshafen Ham Radio 2016 expo. It is a dual-receiver dual-transmitter DDC/DUC HF/6m 10W SDR transceiver with extended measurement capabilities, based on the popular Red Pitaya development board. The RF is converted to the digital domain with a LTC2145-14 125Msps 14-bit ADC (comparable to what an Icom IC-7300 uses, for example), so performance should be pretty good. Receiver coverage is 0-60MHz and +15dB preamp and -6/12/18dB attenuators are available for different levels of frontend gain settings. The transmitter has currently 10W and is optimised for the 160m-6m bands. A higher power amplifier...

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