LTSpice simulation of Baofeng UV5R band selector

I was quite busy the other day trying to understand how Baofeng is using RDA1846 transceiver in their products. While analyzing the schematic it struck me the overcomplicated way they do the switch between UHF and VHF. This is an excerpt of the schematic: The entire selector block is made up with discrete components ! …
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AD8307 RF Power Meter

My first finished KiCad project is a prototype of a RF Power meter with input attenuation built around an Analog Device AD8307. An excellent tutorial about log amps can be read in March 1999 edition of Analog Dialogue. KiCad PCB: And the 3D rendering of the same PCB: The next step will be PCB ordering, …
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TH-D74 BLE or “Bluetooth Low Energy”

Struggling to understand how Universal Unique IDs work (see here) I was wrongly assuming that Core Bluetooth is a framework from Apple that covers all aspects of communication with devices via BT. I was WRONG ! scanForPeripheralsWithServices method and, in general, what I tried to do, for almost a week, is NOT good for my intended …
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Using UUIDs and Bluetooth

I did some more steps towards accessing Kenwood TH-D74’s services via bluetooth. I struggled for some time understanding how discovery based on UUIDs work. I was not aware that, for each service profile, there is a standard Universally Unique Identifier (UUID) documented in Bluetooth SIG specs. Specifically for Serial Port Profile (SPP) service, the UUID …
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Why unsupported central manager state ?

Several days ago I received a Kenwood TH D74 portable transceiver. Although I have a Yaesu FT60 and some other smaller and unimportant transceivers, I don’t have any transceiver that is APRS capable. What’s more important, this transceiver is BT and USB capable, providing serial communication, which opens some interesting opportunities. Today I opened XCode …
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Kenwood TH-D74

We first met — I think — in the summer of 2015 during the Hamfest in Friedrichshafen. At that time I had a mobile Kenwood transceiver TM-D710 which was quite nice by its own. However, after several months using the TM-D710 I got increasingly annoyed by some of its shortcomings, most of them purely subjective (but I …
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Beacon with SiLabs module

This is a beacon project started by my friend YO5VAE. He faced some issues while programming of the Si4463-based module and I thought I might give a hand. I resoldered the entire project on an empty Arduino shield to allow expansion of the project with some additional modules. Below are some pics, but probably the …
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Năsăud Cup, 2017 — Cupa Năsăud, 2017

There is nothing better than marrying several hobbies and have fun from it. I have had the intention to be part of this expedition at least since I heard about this contest for the first time. My good friends from Năsăud planned this thoroughly. All our equipment was carried by three 4×4, manned by a …
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