Amateur radio operator [KE4FOX] wanted to build his own 2M fox hunt transmitter for use at conventions. It would be contained in a 1020 Pelican micro case and attached to a person who would walk around transmitting a signal, leaving the hams to track down the fox. The project uses a DRA818 VHF/UHF transceiver plugged into a low-pass filter combined with a hardware DTMF decoder, all controlled by an ATmega328P and powered by a 11.2 mAh battery.
[KE4FOX] also etched his own PCB, using the PCB toner transfer method, folding a sheet of transfer paper around the board to align both layers. Then he etched the board using cupric chloride. When assembling the board he realized he had made a terrible error, assuming the transceiver module’s pins went in the top layer when in fact they should have gone in the bottom layer. He solved this by soldering in the module in upside down.
He dropped the project into the 1020 and installed an SMA antenna. After he assembled the project he found out that the level shifter he used on the Arduino’s 5 V data didn’t work as expected and it was stuck at a single frequency. Something to work on for V2!
If you’ve never been a patient at a sleep laboratory, monitoring a person as they sleep is an involved process of wires, sensors, and discomfort. Seeking a better method, MIT researchers — led by [Dina Katabi] and in collaboration with Massachusetts General Hospital — have developed a device that can non-invasively identify the stages of sleep in a patient.
Approximately the size of a laptop and mounted on a wall near the patient, the device measures the minuscule changes in reflected low-power RF signals. The wireless signals are analyzed by a deep neural-network AI and predicts the various sleep stages — light, deep, and REM sleep — of the patient, negating the task of manually combing through the data. Despite the sensitivity of the device, it is able to filter out irrelevant motions and interference, focusing on the breathing and pulse of the patient.
What’s novel here isn’t so much the hardware as it is the processing methodology. The researchers use both convolutional and recurrent neural networks along with what they call an adversarial training regime:
Our training regime involves 3 players: the feature encoder (CNN-RNN), the sleep stage predictor, and the source discriminator. The encoder plays a cooperative game with the predictor to predict sleep stages, and a minimax game against the source discriminator. Our source discriminator deviates from the standard domain-adversarial discriminator in that it takes as input also the predicted distribution of sleep stages in addition to the encoded features. This dependence facilitates accounting for inherent correlations between stages and individuals, which cannot be removed without degrading the performance of the predictive task.
Anyone out there want to give this one a try at home? We’d love to see a HackRF and GNU Radio used to record RF data. The researchers compare the RF to WiFi so repurposing a 2.4 GHz radio to send out repeating uniformed transmissions is a good place to start. Dump it into TensorFlow and report back.
The team is hoping to make diagnosing sleep disorders — and other ailments that disrupt sleep like Alzheimer’s and Parkinson’s — a bit easier. Boasting 80% accuracy, the team maintains this is comparable to traditional methods of monitoring sleep cycles using an EEG and technicians — with far less hassle for all involved.
One of the most popular handguns was a former U.S military sidearm (they switched to the Sig Sauer in 2017), the Beretta 92FS/M9 and related variants. The Beretta 92 has firmly established itself as an accurate and reliable pistol that serves well in hostile environments. The Beretta is a great choice as a home defense weapon or as a SHTF sidearm. The Beretta 92FS can be price prohibitive for some.
Fortunately, there is a less expensive clone of the Beretta 92-series called the Taurus PT92, which has been around since the 1980s and uses the same profile. Is it wise spending less money on a PT92, or should you save up your money and get the Beretta?
While we won’t tell you what to do, we will list the differences between the two so you can make that decision.
History and Development
Many people believe that the Taurus PT92 is a recreation of the modern day Beretta 92FS, when it is in fact a clone of the earlier Beretta 92 pistols.
In the mid-1970s, Beretta released the very first Beretta 92 pistol that utilized a heel magazine release, and a framed mounted safety similar to a 1911. Brazil decided to use the new 92 as the official sidearm of the Brazilian Army, so Beretta set up a factory in Brazil to begin producing the 92.
Taurus was an incredibly small Brazilian gun manufacturer that had been most well known for making economic revolvers. When Beretta’s contract for the Brazilian military ended in 1980, they sold the factory (including the blueprints, machines, and workers) to Taurus. It’s a decision Beretta has probably regretted, as in a few years, Taurus went from a small gun company into a major competitor.
The Beretta 92 later evolved into the Beretta 92S, which placed the frame mounted safety to the slide like we see in today’s modern Berettas. The 92S evolved into the 92SB, which moved the magazine release from the heel to the traditional position behind the trigger guard.
The 92SB developed into the 92F and then the 92FS, which squared off the trigger guard and replaced the blued finish with Beretta’s tough Bruniton finish. The Beretta 92FS serves in the U.S Army designated as the M9. Beretta has since developed many more variants of the Beretta 92FS since then, such as the 92A1 and the M9A1, but the 92FS has remained the mainstay in their 92-line.
The Taurus PT92 has undergone many developments in its history. Unlike Beretta, Taurus kept the frame mounted safety but moved the heel magazine release to the traditional location behind the trigger guard. Later, a decocker was added to the PT92 that allowed you to decock the gun without engaging the safety.
PT92 pistols remained in this configuration until 1997, when the cocking serrations on the slide were widened and an internal trigger lock was installed into the gun (all Taurus guns have this). The next major change came in 2005, when Taurus added rails to the PT92 increasing the magazine capacity from 15 to 17 rounds.
Today, the new Taurus PT92 pistols are sold with rails and available in either a matte bluing or polished stainless steel finish. They are consistently available for $150 to $250 less than the Beretta 92FS.
Here is an actual demonstration of the Beretta vs. Taurus:
Advantages and Disadvantages
While the Beretta 92 and Taurus 92 are definitely in the same family of guns, significant differences exist between the two.
Safety location
The most significant advantage to the PT92 is the location of the safety. Granted, if you prefer the Beretta’s slide mounted safety, you may disagree. The safety of the PT92 is located on the frame like a 1911, making it more accessible than the Beretta’s slide safety.
Decocking and safety
The decocking and safety are separate on the PT92. Press the lever down to decock the pistol, and press it up to engage the safety. This means it is possible to carry the PT92 ‘cocked and locked’ like you do with a 1911. The decocking and safety lever on the Beretta are the same: press the lever down, and the gun decocks and engages the safety simultaneously. The Beretta cannot be carried cocked and locked like the PT92.
Finishes
Both can have the corrosion and rust resistant Bruniton finish, of have one of several finishes including stainless steel,
Frame construction
Both use aluminum alloys in the frame construction. While the PT92 is slightly more lightweight in build, the Beretta’s is still slightly longer (though both pistols will probably last longer than you can shoot them).
Grip
The two pistols have minor differences. The forward part of the grip frame on the PT92 is straight, whereas the Beretta’s is curved at the end (it’s been that way since the U.S military requested it) for a fuller grip.
While the Beretta 92FS is not railed like the PT92, Beretta does sell a railed option called the M9A1.
Mags
The 92FS also ships with 15 round magazines out of the box, in contrast to the PT92’s 17 round mags. Factory Beretta 17-round magazines are available for purchase separately. Mec-Gar (an aftermarket supplier of pistol magazines) manufactures 18 round magazines for both pistols. Firepower between the two pistols is equal.
Which is more reliable: the Beretta 92FS or the Taurus PT92?
In terms of reliability and accuracy, the Beretta and Taurus seem to be on equal footing. The Beretta definitely has a superior track record having served the U.S military servicemen and law enforcement officers, and military units all over the globe. The PT92 has seen military and law enforcement service across the world, but not nearly as much as the Beretta.
Quality and accuracy
This isn’t to say that the Taurus is a worse gun than the Beretta. The two pistols are nearly identical in basic design. After all, the PT92 was constructed based on Beretta 92 blueprints with the same machinery and workers, and what they perfected Taurus went back and added details to their newer ones. In that regard, overall quality and accuracy between the Beretta and the Taurus should be considered on equal ground as they used one another to improve the original design.
Optimizing the Beretta 92 for Self-Defense:
Conclusion
When it comes down to it, if you’re on a budget or have been trained to use a 1911, you’ll probably prefer the Taurus due to its lower price and safety position respectively. If you want the original manufacturer of the 92-series, prefer the slide mounted safety, or feel more comfortable with Beretta’s track record go with the Beretta 92FS or one of its variants.
In Europe, the GRAVES radar station beams a signal on 143.050 MHz almost straight up to detect and track satellites and space junk. That means you will generally not hear any signal from the station. However, [DK8OK] shows how you can–if you are in Europe–listen for reflections from the powerful radar. The reflections can come from airplanes, meteors, or spacecraft. You can see a video from [way1888] showing the result of the recent Perseid meteor shower.
Using a software-defined radio receiver, [DK8OK] tunes slightly off frequency and waits for reflections to appear in the waterfall. In addition to observing the signal, it is possible to process the audio to create more details.
Why is there a giant vertical radar transmitter in the middle of France? The transmitter uses a phased array to send a signal over a 45-degree swath of the sky at a time. It makes six total steps every 19.2 seconds. A receiver several hundred miles away listens for reflections.
Even the moon reflects the signal when it is in the radar’s path. If you are interested in a moon bounce, you may be able to build a station to hear the reflections without being in Europe.
So: first post, five months into learning, and nine really brief LDs. This forum is such a great resource, and I'm hoping to get some input on the areas I struggle with.
I read a lot of people saying that when you RC "you should feel that you could be dreaming at that very moment". And I never can. I believe the first one of the day, when I wake up - "this could be a false awakening". But then, if an hour later, I see one of my dreamsigns (chocolate, comics or animals!) and say; "this could be a dream", my brain instantly replies: "um - no it couldn't, becase I remember that nose pinch I did an hour ago when I woke up, and I haven't gone to sleep since then, and I remember what I've been doing in the house since I got up, and it hasn't changed shape or location in that time at all, so I know I'm still awake". So that thought goes through my head in a flash, and before I can even nose pinch - I've talked myself out of believing. And so it goes all day.
I can role play it and say : "what if I had a dream tonight that was just like this, and then I'd do a nose pinch and discover I was dreaming" - and act that out - maybe that'll be as far as I can get. But do people really believe they might be dreaming when they RC ? Even when you remember doing your last RC earlier in the day?
Jo
via Lucid Dreaming - Dream Views - Attaining Lucidity http://ift.tt/2xyRgpW
As the LoRa low-bandwidth networking technology in license-free spectrum has gained traction on the wave of IoT frenzy, LoRa networks have started to appear in all sorts of unexpected places. Sometimes they are open networks such as The Things Network, other times they are commercially available networks, and then, of course, there are entirely private LoRa installations.
If you are interested in using LoRa on a particular site, it’s an interesting exercise to find out what LoRa traffic already exists, and to that end [Joe Broxson] has put together a useful little device. Hardware wise it’s an Adafruit Cortex M0 Feather with onboard LoRa module, paired with a TFT FeatherWing for display, and software wise it scans a set of available frequencies and posts any packets it finds to the scrolling display. It also has the neat feature of logging packets in detail to an SD card for later analysis. The whole is enclosed in a 3D printed case from an Adafruit design and makes for a very attractive self-contained unit.
