A Doppler Radar Module From First Principles

If you’ve ever cast your eyes towards experimenting with microwave frequencies it’s likely that one of your first ports of call was a cheaply-available Doppler radar module. These devices usually operate in the 10 GHz band, and the older ones used a pair of die-cast waveguide cavities while the newer ones use a dielectric resonator and oscillator on a PCB. If you have made your own then you are part of a very select group indeed, as is [Reed Foster] and his two friends who made a Doppler radar module their final project for MIT’s 6.013 Applications of Electromagnetics course.

Their module runs at 2.4 GHz and makes extensive use of the notoriously dark art of PCB striplines, and their write-up offers a fascinating glimpse into the world of this type of design. We see their coupler and mixer prototypes before they combined all parts of the system into a single PCB, and we follow their minor disasters as their original aim of a frequency modulated CW radar is downgraded to a Doppler design. If you’ve never worked with this type of circuitry before than it makes for an interesting read.

We’ve shown you a variety of commercial Doppler modules over the years, of which this teardown is a representative example.

via Radio Hacks – Hackaday http://bit.ly/2YT59wC

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Lucid Dreaming | ADA/Mindfulness training

I'm interested in training myself to actually live in the present and be aware of my thoughts and surroundings for long periods of time, for DILDs and because of health problems which would benefit from long-term mindfulness. But I don't want to exhaust myself. Here's an idea I have for gradually building up awareness:
Every time I do a reality check (usually once or twice every hour), try to stay aware for one minute and do this for 3 days. Then try 3 minutes after each RC for another few days. then 5 minutes and so on until I'm aware more often than not. Is this likely to work? Could anyone suggest a possibly better way?

Also, how do you stay aware when doing things which require you to think and concentrate? For example writing or talking to someone?

via Lucid Dreaming - Dream Views - Attaining Lucidity http://bit.ly/2KcMt6R

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Lucid Dreaming | Smart watch or something to train RC?

Hey guys, I've been doing my best keeping up with my gravity RC or ADA style practices.

While I do it sporadically throughout the day I do still get lost in automatic mode though. I want get to the next level! And yeah I tried using an interval alarm, or an audio on my phone, but it could disturb others and I can't have it on all the time.

So I'm trying to find some device that could help remind me to do it a bit more often and consistently. I thought a smart watch or a fitness wristbands would be great for this. If it could vibrate once every few minutes it wouldn't disturb anyone that much and I could keep it on most of the day too.

I was looking around and I found these for pretty cheap:

Wear24
miband 3
amazfit bip

Does anyone has experience with these or uses something similar, or better? Basically I wanted to get something easy to carry around anywhere, vibrates(so it's relatively silent, or maybe has a speaker), cheap and disposable so I can stop using it when I'm satisfied with my progress.

Thanks :)!

via Lucid Dreaming - Dream Views - Attaining Lucidity http://bit.ly/2LX2fFv

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Using a Cheap Handheld Radio As A Morse Transceiver

Both grizzled hams and potential future amateur radio operators are well-served by the market these days. Powerful and capable UHF and VHF handheld transceivers can now be had for well under $100, something unimaginable as recently as 20 years ago. Of course, a major part of the amateur radio scene used to be Morse code. Not to worry though, you can do that with a handheld, too!

The setup is simple but effective. A Morse code training unit generates tones in response to input from a Morse keyer. This audio is passed into the headset port of a Baofeng handheld transmitter. A toggle switch is wired up to the Push-To-Transmit circuit of the Baofeng to trigger transmission when required.

It’s a little different from the more typical constant-wave transmission methods that are so seldom used nowadays, but it gets the job done. Morse code has always been appreciated in situations where voice transmission is difficult due to low bandwidth or interference, and now it’s easy for new hams to give it a try.

Morse code can be a trial to learn, but spare a thought for the folks who had to pick it up back in 1939. Video after the break.

via Radio Hacks – Hackaday http://bit.ly/2Vzwty1

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Pluto (SDR) Goes Ethernet

Pluto may no longer be a planet, but it is still a fun software defined radio (SDR) set up from Analog Devices. The inexpensive radio uses a USB connector and looks somewhat like a network connection to your PC. But what if you want to really use it with a network? [SignalsEverywhere] shows you how to do it using a USB network adapter and a USB connection adapter.

Just plugging a USB dongle into the box isn’t sufficient, an extra power supply is required as well as a minor bit of configuration. The IP address will be static so you might want to use an IP that your DHCP server won’t hand out, or reserve the IP on your local network.

The Pluto SDR is an inexpensive ($150) student kit that can both receive and transmit (at very low power). There’s a free book about it, too. By default, the device only operates from 325 to 3800 MHz — too high to receive the FM radio band, for example. However, there is a hack that not only makes the range from 70 to 6000 MHz, but also increases the bandwidth from 20 MHz to 56 MHz. It may not be totally “in spec” in the increased range, but it works fine to pick up FM signals, for example. The official page hints this only works with certain units, but we’ve known quite a few people to get it to work, so it will likely work for you, too.

In addition to increasing the frequency range, you can enable the device’s 2nd CPU which is disabled by default. If you want to do a little more hacking, there’s a custom firmware for it that turns it into a stand-alone streaming device — handy with the Ethernet hack. You can download PlutoWeb from GitHub.

 

via Radio Hacks – Hackaday http://bit.ly/2HaX6oS

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Lucid Dreaming | How do I remember my dreams vividly? Any tips?

Been having trouble with this, anyone got any tips?

via Lucid Dreaming - Dream Views - Attaining Lucidity http://bit.ly/2JoN9FO

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Clock Radio Receives Upgrade

Before everyone had a cell phone alarm to wake them up in the mornings, most of us used clock radios that would faithfully sit by our beds for years. You could have either a blaring alarm to wake you up, or be gently roused from slumber by one of your local radio stations. These devices aren’t as commonly used anymore, so if you have one sitting in your parts drawer you can make some small changes and use it to receive radio stations from a little further away than you’d expect.

This Panasonic clock radio from [Ryan Flowers] has several upgrades compared to the old clock radio hardware. For one, it now can receive signals on the 7 and 14 MHz bands (40 and 20 meters). It does this by using separate bandpass filters for each frequency range, controlled by a QRP Labs VFO kit which can switch between the two filters automatically once programmed. The whole thing is powered by 8 AA batteries, true to form with a clock radio from the ’90s.

[Ryan] notes that his first iteration was a little quiet but he’s now able to receive radio stations from as far away from Japan with this receiver. Even without a license, you can make these changes and listen in to stations from all around the world, as long as you don’t start transmitting. If you want to make a small upgrade from this clock radio though, it’s not that hard to get into.

via Radio Hacks – Hackaday http://bit.ly/2vE1lCR

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Full Earth Disc Images From GOES-17 Harvested By SDR

We’ve seen lots of hacks about capturing weather images from the satellites whizzing over our heads, but this nicely written how-to from [Eric Sorensen] takes a different approach. Rather than capturing images from polar satellites that pass overhead a few times a day, this article looks at capturing images from GOES-17, a geostationary satellite that looks down on the Pacific Ocean. The fact that it is a geostationary satellite means that it captures the same view all the time, so you can capture awesome time-lapse videos of the weather. 

The fact that GOES-17 is a geostationary satellite means that it is a bit more involved. While polar satellites that orbit at an altitude of 800km or so can be received with a random piece of wire, the 35,800 km altitude of geostationary satellites means that you need a better antenna. That doesn’t have to be that expensive, though: [Eric] used a $100 parabolic antenna and a $100 Airspy Mini SDR receiver connected to an Ubuntu laptop running some open source software to receive and decode the 1.7GHz signal of the satellite.

The other trick is to figure out where to point the dish. Because it is a geostationary satellite, this part has to be done carefully, as the parabolic antenna has only a small receiving angle. [Eric] designed a 3D-printed mount that fits onto a tripod for his antenna.

Capturing satellite weather images is a fascinating thing to do, and this adds another level of interest, as the images show the full disc of the earth. Capture a series over time, and you can see storms spin around and across the ocean, and see just how complicated they are.

If you are looking for a simpler way to get started in receiving weather satellite images, check out this guide to converting an old TV antenna and USB receiver to capture images from polar satellites.

via Radio Hacks – Hackaday http://bit.ly/2WoGGyj

Lucid Dreaming | Had a series of dry spells, now I'm trying to remember basic practices.

I've had abnormally low LD rates for the past several months. Between June 2017 and November 2018, I had an average of 23 LDs per month (median of 17). In the last 6 months, I've gotten between 5-15 per month, and I'm really struggling to break out of that.

I try to cover the basics:
-General Daytime Awareness (nose plug RC, 10-15/day; started using the Gravity RC)
-Detailed Dream Journal (variable levels of detail)
-Getting enough sleep (8 hours is the target)
-Having a regular schedule

I feel like I'm missing something critical that I forgot. So, I'm currently studying everything I did to achieve high rates in the last 2 years. Here's a couple of things I did:

-Alternating Strategies - Every night, I attempted either WILD or Full WBTB + SSILD, switching between them every night. This arguably gave both approaches a higher success rate than doing either of them exclusively.
-WBTBs were ~8-20 minutes each.
-Burnout has been practically nonexistent, including in these recent months. It happens, but not often.

A large number of LDs were spontaneous DILDs. Hopefully the Gravity RC will help in bringing those back.

I think I should WILD like it all depends on WILD, and RC like it all depends on DILD. I think that recently I've been slacking in RCs because I've been depending on WILD being successful; which has not turned out as well as I'd like so far.

I posted this in the hopes that the wonderful folks of DV could help me fill in the gaps.

via Lucid Dreaming - Dream Views - Attaining Lucidity http://bit.ly/2DLvSmV

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