radio, electronics, security, silly hacks
The uSDX+ is a nice little transceiver from china based on the uSDX project. It is cheap, works on 8 bands, is based on opensource software, and has enough place inside the case to do some modifications. And if it breaks, it is easy to fix (probably easier than many analog radios).
So let’s see what we can modify in this radio.
The following modifications will be for the uSDX+ (uSDX plus), with the board marked Ver 3.0, but other radios may be similar and similar modifications may apply.
The (tr)uSDX has hardware to measure the power amplifier voltage/current/input power. Since the output power is also measured, it can calculate and show efficiency. This is very useful for tuning the class-E output stage, and is also useful in the field to see battery voltage and other parameters.
I have an uSDX+ transceiver from China. Let’s add the power monitor to it too. This description should apply to other radios based on the uSDX.
Continue reading “Adding an INA219 power monitor to a chinese USDX+ transceiver”
The (tr)uSDX transceiver has a builtin SWR meter. It will measure SWR and forward/reflected power. This is very useful in the field, because there is one less device to carry.
I have an uSDX+ transceiver from China. Let’s add the SWR meter to it too.
Continue reading “Adding an SWR meter to a chinese uSDX+ transceiver”
This is a demo of a working replica of the Great Seal Bug.
As far as i know this is the only attempt to make a working replica, not only a nicely looking prop.
I am a licensed radio amateur (callsign SQ5BPF), therefore the device dimensions were scaled to make it operate on the amateur radio 23cm band (1240-1300 MHz). Please see my other articles about this device.
This is the third part of articles about the Great Seal Bug (also called “The Thing”). These articles will cover: history, theory of operation and a practical reconstruction of this device. This part is about building a working copy of the Great Seal Bug
To my knowledge this is the only publication about making a wirking replica of the Sreat Seal Bug. https://www.vintagespycraft.com/ shows a beautifully looking model, however the emphasis was on making it a nice looking exhibit, and not on making it work (but look at this site anyway, the model is a work of art).
In 1945 this was super-secret, ultra-novel military technology. Building and operating it required special materials and access to ultra-secret hardware. So is it possible to do this in 2022 on an amateur budget? Surely not.
But radio amateurs have a long history of doing “impossible” things, part because of their ingenuity, and part because of their ignorance (they simply don’t know something can’t be done). So lets try anyway 🙂
Continue reading “The Great Seal Bug. Part 3: Building a working copy of The Thing”
This is the second part of articles about the Great Seal Bug (also called “The Thing”). These articles will cover: history, theory of operation and a practical reconstruction of this device.
This part is a short explanation the theory of operation.
Continue reading “The Great Seal Bug. Part 2: theory of operation”
This is the first part of articles about the Great Seal Bug (also called “The Thing”). These articles will cover: history, theory of operation , a practical reconstruction of this device and a working demo.
This device, even 75 years later, is still often mentioned at security publications and conferences.
Astec AA21660 power supplies can be modified to give 13.8V / 24A.
They are specified to 24A @12V and 27A @5V, with 400W max continuous power. It is used in various Engenio (former LSI Logic) storage products, which are OEM-ed by many companies: IBM (TotalStorage DS4xxx and DS5xxx line), NetApp etc. The IBM FRU is 19K128.
The following mods change the overvoltage protection to 14.4V, and set the voltage to 13.8V.
Continue reading “Astec AA21660 power supply modification for 13.8V output”
So I’ve tried to operate from Platanias / Crete (see SV9/SQ5BPF with uSDX part 1).
Threw a wire on a palm palm tree, stretched a counterpoise on the ground, tuned it, and made the first CW QSO on 40m with Zygi SP5ELA. So next I’ve tried to tune the antenna on 80m, and the uSDX transceiver failed with a short circuit.
It seems that the smd PA transistor died on 80m (it also dies on 10m). Fortunately I’ve had two IRLML2060 transistors with me, but no soldering iron and other tools.
So is there any hope that i will be able to make more than one QSO?
I have traveled to Crete / SV9 in July 2021 for vacation. I’ve spent vacation in Greece many times. This time i brought a shortwave transceiver with me to see if amateur radio will be compatible with a family vacation.
