Thursday, February 20, 2020

Stout Homebrew Radio Pumps Out 200W of AM Goodness

In this day and age, with cheap online shopping, software defined radio and bargain-basement Baofengs from China, the upstart radio ham is spoilt for choice. Of course, there’s nothing quite like the charm of keying up your own homebrewed rig, cooked up in the garage from scratch. [Paul], aka [VK3HN], knows just how it feels, and put together an epic 200 watt Class D AM rig to blast his signal on the airwaves.

An example of an Arduino used in one of [Paul]’s builds.
It’s a build following on from the work of another radio ham, [Laurie], aka [VK3SJ]. Younger hackers will note the Arduino Nano at the heart of the project, running the VFO and handling all the relevant transmit/receive switching. We can only imagine how welcome modern microcontrollers must have been to old hands at amateur radio, making synthesizing all manner of wild frequencies a cinch.

The amount of effort that has gone into the build is huge. There are handwound coils for the PWM low-pass filter, and the PCB is home-etched in ferric chloride, doing things the old-school way. There’s also a healthy pile of dead components that sacrificed their lives in the development of this build. Perhaps our favorite part is the general aesthetic – we can’t get over the combination of hand-drawn copper traces and off-the-shelf Arduinos.

Many components perished in the development of this powerful rig.

It’s a build that far exceeds the Australian legal limits, so it only gets keyed up to 120W in real use. This has the benefit of keeping the radio operating far in the safety zone for its components, helping keep things cool and stable. We’re sure [Paul] will be getting some great contacts on this rig. If you’re suffering from low power yourself, consider an amplifer build. Video after the break.

[Thanks to Ben for the tip!]



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Lucid Dreaming | Pain Induced Lucid Dream

Hey!

This technique is probably already a thing in certain ways, but as I was trying to figure out some common dreamsigns I naturally thought of pain as a powerful dreamsign. It’s something quite common in dreams and happens throughout the day, every day.

I thought of it for a minute or two and then moved on with my schedule not thinking much more about it. Some half an hour later I was walking barefoot down a beach and stepped on a small rock and that small physical sting immidietly made me think about my dreamsign because it was so sudden and painful for just a mere second.
That made me think about the potential about it, and as I was scrollin thru some jibberish on internet I stumbled upon the idea of inducing small portions of pain in a (sane) manner, like a small electro shock for instance.
There is actually a specific bracelet that’ll give you a gentle shock to prevent you from continuing bad habits and I thought of it, why not use these small electroshocks as a dreamsign?

I mean, think about it, pain is harsh, sudden and will snap you out of almost any daily activity that you do, and if you make it your dreamsign you’ll also be able to do it during your REM periods throughout the night, externally inducing your highly familiar dreamsign over and over. Of course, this idea is based on the shocks not being to harsh and not waking you up. But with a little tweaking I think you’ll stay fast asleep.

I know La Berge has been doin quite some research about stuff like this, but his work was more focused on lights and vibrations instead.
In his book he describes how successful the attemps were and the lightcue seemed to be the most reliable source.
In my head pain sounds and should be more powerful, so well, is this thing tested by anyone and what’s your ideas regarding this?


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Monday, February 17, 2020

What To Do If You Get Lost: Urban, Rural and Wilderness Scenarios

I had moved to a new city about two weeks prior. I worked in another new city about 15 miles north. I had two established routes to and from work, but I wanted to find some shortcuts.

I took a turn off a main route, thinking it would intersect my street. I spent two hours driving in circles, my gas running out, having to pee, and growing increasingly angry.

I made a number of turns down dead end streets. I finally found my street and made it home. A number of years later, I am closely familiar with the area, and I often reflect on how close I was to home that night.

Getting lost means you are disoriented as to the location of your intended destination, or you are uncertain of your current location. It can be annoying and frustrating, to downright panic inducing, or fun and exciting.

Some of the information here also applies if you are oriented, but your vehicle breaks down, or on foot and injured.

Don’t Get Lost

Learn to navigate. It is much better to prevent getting lost in the first place. Knowing what to do if you are lost is damage control to one extent or another.

  • Stay oriented: At this moment, without a compass or other aid, can you identify north, south, east, and west? In an urban area, do you keep track of street signs and buildings?
  • In an urban or rural area, plot a course. Before you leave, map out your directions with Google Map, and print it out. I still like to use Jimapco paper maps, and post it notes. It is a familiar and comforting ritual to spread a map out, trace a route, and then put the directions on post it notes, or in a steno books. I refer to the written directions en route, and also record the time and distance to self-defined checkpoints. A checkpoint is a milestone in your route. It could be a particular intersection or building.
  • Learn how to read a paper map. I suspect this is a dying skill. I don’t think it’s healthy or a good idea to rely exclusively on electronic devices. To be well-rounded, more skilled, and versatile, keep paper skills current.
  • Use landmarks. What features in a urban, rural or wilderness area stand out? Landmarks can be synonymous with milestones.
  • Use a GPS (Global Positioning System) Unit, but don’t rely on it exclusively.
  • Compass: Learn how to read a compass.
  • Look behind you. The purpose of this is to recognize your route on the way back. You can also leave a trail of electronic breadcrumbs. Video or take images of key transition points such a forks in the trail.

Be Prepared in Case Step One Fails

  • Complacency and assumption are the mother and father of all screw-ups. Are you prepared for reasonable as well as some unreasonable eventualities? What is your EDC? Do you change your EDC based on travel and destination?
  • Have a full tank of gas, water in your vehicle, and keep your vehicle well maintained.
  • Keep yourself fueled, hydrated, and well maintained.

Factors to Consider When Traveling

  • Are you on foot or in a vehicle?
  • Alone or with a friend or a group?
  • With a child?
  • Are you a man or woman? (those are the only two options BTW).
  • Are you fit and in good health, or sick or injured?
  • Night or day?
  • What are the current and imminent weather conditions.
  • Your EDC and other gear you have available
  • Do you have cash on hand/cards?
  • Do you have a hand-held device or other means of communication/orientation, and service and adequate charge for your device? Don’t forget to carry a charger or batteries.
  • Where are you lost, an urban, rural, or wilderness area?
  • If you like to travel alone, precautions should be taken. If you are a woman, there are also some additional considerations. Before venturing out alone, here are my habits:
    • I email three people informing them of my departure and estimated return time, and my itinerary, and the phone for the local PD.
    • I leave three redundant voice mails to the same people with the above information.
    • I make certain as possible my vehicle is in top shape, with the tank topped off.
    • I have extra cash, three to six liters of water, and my BoB in my vehicle.
    • I have my EDC and my Man-bag.
    • I have a course plotted on paper, with post-it’s on the map.
    • I have checked the weather along my route.

Change Your Mindset

Getting lost is not a nightmare or horror story unless you make it into one. Being lost is an adventure. Explore what is around the corner. You never know what you might find.

There is a difference between a tourist and a traveler. A tourist sticks to the well-known attractions, main roads, and the proverbial well-beaten path. A traveler tends to be more adventurous and an explorer.

What to Do if Lost in an Urban Environment

Urban areas are densely populated. Depending on what state you live in, you will refer to one city in your state as The City.

In New York State, the obvious choice in New York City. In an urban area, there will be multilane and elevated highways, long high bridges, dense traffic, and buildings, including skyscrapers.

There will be road signs everywhere, sometimes too numerous to track. Urban areas are packed with people on foot, bicycles, and motor vehicles. There will be crowds, lots of noise, and a miasma of smells, depending on where you are in the city and the time of day or night

Major cities will never sleep. Businesses, mostly supermarkets and convenience stores, will be open 24 hours a day, and bars and clubs into the early morning hours.

If you are in an unfamiliar city, or unfamiliar part of your own massive city, e.g., New York, Los Angeles, or Chicago, you can get lost. Don’t ever look like you are lost.

Pick a spot 50 or 100 meters ahead of you and walk to it like you have been there a hundred times, and it is your intended destination. A store is a good option. Once you get there orient yourself.

Do not look confused, hesitant, change direction within a few steps, look scared or uncertain, or look around. And whatever you do, don’t look up at the skyscrapers. That will mark you immediately as someone out of town.

Why is this so important? Because you will start looking like a good victim. The other feature of dense urban areas are pockets of high crime. There are predators out hunting, and you do not want to look like their prey.

Chances are you will be able to orient yourself with a GPS, landmarks, or calling someone for directions. You can also ask a stranger/store employee for directions; though this can make you feel like a tool-bag.

This can also be a good time to find a cafĂ©, sit and get a cup of coffee, and chill and orient yourself or make a phone call. This is not a big deal; just part of your trip. Unless you are in a very upscale neighborhood, it is ill-advised to knock on strangers doors in an urban area. Stick with store employees for directions, and do it discreetly enough where others don’t hear and butt in.

On a related note: don’t forget where you parked. If you are driving a rental, make certain you know what it looks like. This may sound obvious, but under stress, we default to what we are familiar with.

No sense automatically looking for the car 1500 miles away in your driveway or at an airport. Take an image of the freaking car if you have to.

What to Do if Lost in a Rural Area

Rural areas or the country are sparsely populated. It is unlikely to find buildings more than three stories high. There will be the ever-present convenience stores with gas pumps, and there may be a few big box stores here and there.

Some of the businesses will close as early as 5:00 PM, and it may be difficult to find a place open after 9:00 PM. Rural areas are mostly woods and farmland, with minimal development.

Homes are spread out and there may be a mile or three between neighbors. There will be mostly two lane roads, and some dirt or gravel roads. There will be rolling hills, winding roads, short bridges over creeks and streams, and maybe mountains to ascend and descend.

If you get lost in a rural area, you can again orient yourself with landmarks. Lakes, rivers, and mountains will be more likely, though you can use unique buildings as well.

If you come across an open store, you can ask for directions. You will be generally safer knocking on a door in a rural area than in a city but use caution. Move slow, smile, keep your hands in site, and give a lot of space.

What to Do if Lost a Wilderness Area

Wilderness areas or the woods are undeveloped. In the northeast and Pacific northwest, there will be hardwoods, pines, creeks, rivers, ponds, lakes, mountains, dense tree canopies, and wildlife.

In the continental United States, we have deserts in the southwest, that are hot in the day, but can get cold at night. There may be well-marked and travelled or minimal trails.

You may not encounter other people, or an encounter with someone else will be rare. It will be pitch black at night, but the moon and stars will be bright, and you will be able to see the Milky Way once your eyes adjust.

  • Stay on trails. If necessary, you can backtrack.
  • Do not daydream. Stay aware of your surroundings, landmarks, and stay oriented with compass and/or GPS checks every few minutes.
  • Bring fluorescent tape,, and mark your trail. This is a good practice for beginners who venture into the wilderness, or even experienced outdoorsmen in new, unfamiliar terrain.
  • Be prepared. This means you have well developed basic outdoor skills, and good quality clothing and other gear. This will give you confidence and help you stay calm if you do get disoriented. When I was a teen first going into wilderness areas, I always had at minimum a doubled Ziploc bag with the following items:
    • 2 boxes water-resistant matches
    • A candle stub
    • A cigg lighter
    • A snickers bar
    • A tin of sardines
    • A roll of life savers or some hard candies
    • Toilet paper
    • 15 feet of para-cord
    • Socks
    • A reflective mylar blanket
    • Band-aids.
    • A folding knife and Chapstick in my pants pocket.
    • A compass in my jacket pocket.

If you get lost in a wilderness area, the recommendation I consistently heard growing up (1970’s & 1980’s) is to stay put and wait for rescue. This was also directed to a young teenager going into a remote wilderness area with six to eight men before GPS or cell phones.

If you are experienced in the outdoors, fit, and well equipped, you have a few hours of daylight, and the weather is decent, you may be able to re-orient yourself and find your way out.

Before you do anything, sit down, have some water or coffee and a snack (you have these items with you, yes?). Get calm and focused.

  1. STOP.
  2. Stay Calm. Don’t start running. Sit, hold still, and collect yourself.
  3. Think. What was the last familiar place you recall? Which direction were you travelling?
  4. Observe. Look around for anything familiar. Take inventory of your supplies. The latter can also contribute toward feeling calmer.
  5. Plan. Are you going to stay put or find your way out?

If you intend to walk out, start looking for the bright orange or green tape mentioned above that you have placed. Mark your current position with tape so you don’t walk in circles, note any landmarks, and look for the trail or the last familiar landmark before you got lost.

An overview of your position may coalesce in your head and you will be oriented again. There is also the old and often cited method of seeking high ground to orient yourself. I have doubts about this method; you may get even more turned around.

If you are sick or injured, it is dusk, or there is a snowstorm/freezing rain coming in, you will have to decide if you are going to wait for rescue or try to make your way out.

If you have a phone, radio, or other communication device, you can call for rescue. You may not have service in a wilderness area. This is where preparation is critical. If you have to/choose to stay put, can you make a shelter and fire?

lost child

What if Your Child Gets Lost?

Once again, focus on prevention and preparation.

  • Have current photos of your child.
  • Your child needs to know the full names of both parents, their phone, and address. I remember carrying a simple, homemade laminated ID when I was a child. It had my name, my parents names, and our phone and address on it. Make an ID for your child. Dog-tag style IDs are another option.
  • Teach your child what to do if they get lost.
    • Stay put if you get lost so parents can find you.
    • How to make a phone call.
    • How to ask for help in a safe manner. E.g., if you are in a store, look for someone who works there.
  • If you are in a store, tell an employee. They can make an announcement, or check people exiting the store.
  • If you can’t locate your child promptly, call the PD. Don’t hesitate on this.

Some of the above may also be applicable to an elderly relative with dementia.

Conclusion

Part of developing self -sufficiency and self-reliance is developing the skills of navigation, outdoor survival, and interpersonal communication skills.

A central theme in this article is prevention and preparation. Don’t get lost. Once you are lost, you are doing damage control.

getting lost Pinterest


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Sunday, February 16, 2020

Closed Ham Radio Peripheral Reveals Its Windows Secrets

The student radio society in Trondhjem owns a Flex 6500-radio, with its associated Maestro panel peripheral. This is a software defined radio, and the Maestro is a computer containing just enough of an embedded version of Windows to run its front-end software. Unfortunately for our Norwegian radio amateur friends it runs very little else, even to the extent of being unable to connect to public WiFi that requires a web log-in. This was particularly annoying as the student network does this and they’d had to create their own hotspot, so they’ve provided some details on how they were able to open it up a little to do a bit more.

At first they were cagey about the exact nature of the exploit they used to penetrate the device’s defenses, but since then they’ve published a second installment with full details. It involved gaining access to the filesystem and a terminal through a right-click menu from a web browser screen within the Maestro software, then using that access to change configuration such that it could be exposed across the network. From there they were able to treat it much as they would a normal Windows installation, including putting other software such as SmartSDR onto it.

This piece of work provides a fascinating insight into an embedded Windows device, and leaves us as usual surprised by the ease of the exploit. We’d say it’s something of a brave move for a company to ship a feature-limited product to radio amateurs of all people, a community that has been experimenting and finding whatever means  to extend the capabilities of their equipment for over a hundred years. Perhaps Flexradio’s eyes are on greater things.



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Saturday, February 15, 2020

Wall Panels With 3760 Antennas Can Increase Wireless Range

Most of us know that to get the best possible WiFi signal, you want there to be as few walls as possible between you and the Access Point. But that might soon change, as researchers at MIT have found a way to make surfaces increase signal strength. Called RFocus, the technique uses a wall panel covered in simple antennas to dynamically focus or reflect RF energy towards a intended receiver.

The normal methods to increase wireless range usually involve increasing the transmitter output or adding larger, more efficient, or directional antennas to the receivers and transmitters. But these techniques are limited when you need to the reduce power consumption and size of the devices. The MIT teams approached the problem from a completely different angle, by optimizing the environment.

The wall panel in question consist of 94 PCBs, each containing 40 passive antenna elements in the form of copper rectangles. Each element is a quarter wavelength long (125 mm for 2.4 Ghz), and on its own it doesn’t have any real effect on the signals, allowing it to pass through the panel. Between the ends of elements are small RF switches, that can close to combine two antenna elements into single half wavelength antenna, creating a reflector. When this is applied across the panel in different patterns it can effectively beamform the signal to focus it at different points in space.

The RF switches are connected to shift registers, which are all controlled via a single SPI bus with an Arduino. Each RF switch is activated in a pseudo-random sequence, changing the configuration of the panel 10,000 times in 100 ms. The signal strength at the receiver is reported to the panel controller for each configuration, allowing the controller to select the best configuration for any single transmitter. In a scenario where multiple low-power sensor nodes are deployed, this can allow the receiver to “focus” on each node in turn. The full paper is a very interesting read, downloadable as a PDF.

RF is generally considered the black magic of electronics, but it can all become a bit clearer with a basic knowledge of antenna theory and modulation schemes.

Thanks to [Qes] for the tip!



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AAA Powered LoRa Mailbox Sensor Goes the Distance

As more of the world’s communication moves into the electronic realm, a casualty has come in the physical mail. Where once each new day might have brought with it a bulging mailbox, today it’s not uncommon for days to pass with not even so much as a bill or a coupon book. For [Eivholt] this presents a problem: he doesn’t want to miss a parcel but most visits to the mailbox are futile. His solution is a LoRa-connected mailbox monitor that sips power from a pair of AAA batteries to the extent that so far it’s run for over two years on a single set.

At its heart is a single board, a Talk2 Whisper Node. This packs a low-power version of the ATmega328 microcontroller alongside a LoRa radio and an efficient power regulator allowing it to draw only 8.70 uA in standby mode, waking up only for extremely short periods to check for mail and report via LoRa to The Things Network. The sensor is simply a microswitch, selected after finding a reed switch problematic to install. Finally an SDR was used to debug the operation of the radio.

The write-up also provides an introduction to extreme low power projects, including some tips on measuring such tiny currents. Even if you have no interest in a mailbox, any tricks that can help maximize power efficiency are always worth taking a look at. Check out the video after the break to see this radio-equipped mailbox in action.



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Friday, February 14, 2020

RF Shield Turns Arduino (And PC) into Shortwave Radio

Microcontrollers tend to consume other kinds of electronics. A project you might once have done with a 555 now probably has a cheap microcontroller in it. Music synthesizers? RC controllers? Most likely, all microcontroller-based now. We always thought RF electronics would be immune to that, but the last decade or two has proven us wrong. Software-defined radio or SDR means you get the RF signal to digital as soon as possible and do everything else in software. If you want an introduction to SDR, Elektor now has an inexpensive RF shield for the Arduino. The Si5351-based board uses that oscillator IC to shift RF signals down to audio frequencies and then makes it available to the PC to do more processing.

The board is available alone or as part of a kit that includes a book. There’s also a series of Elektor articles about it. There’s also a review video from Elektor about the board in the video, below.

We peeked at the schematic and the shield is more for letting the Arduino control the radio by changing the oscillator frequency rather than performing the SDR functions. The IQ signals appear on the PC’s soundcard via a microphone or line-in jack, and don’t really route to the Arduino.

That’s a shame because some of the 32-bit Arduinos might be able to do some interesting things with the right hardware. Plus there are many capable CPU and FPGA boards that have Arduino shield-compatible layouts. That could have led to some interesting possibilities.

Then again, having a programmable signal source on the Arduino isn’t a bad thing and compared to the older version of the board, the new board offers easier breakout for the oscillator signals.

If you want to learn more about how SDR works, try starting with spreadsheets. However, if you want to graduate to something more practical, try our series on GNU Radio.

 

 



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