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Posts Tagged ‘Electronics’

Foxx 3 TRX build

December 2nd, 2013 |

So it was my birthday recently and to celebrate the turning of another year and that I had indeed taken a day off – I decided to build a FOXX 3 QRP CW transceiver. These little kits are available from Kanga-products.co.uk and are designed to fit in a Altoids tin.

The kit comes pre bagged up in separate bags, and its just a case of soldering the correct component to the correct area on the circuit board. The kit itself is a 1 Watt QRP transceiver that can be bought on various bands. Mine was for the 20m band.

The board has a clear and easy to read Silkscreen and the pads are suitably wide enough to allow anyone with different levels of skill to create the kit. Each step allows you to test each part of the board, so you learn how each part of the kit relates to the transceiver as a whole.

I had a great time building it, it’s a simple, easy and great fun little kit. I hope to take it out and about – so hopefully you can hear my tiny signal on 20m soon.

Where to find the $20 Software Defined Radio?

December 1st, 2013 |

Author: Owen KF5CZO

A while back I wrote a blog post about the availability of $20 software defined VHF/UHF radios in the form of re-purposed USB digital television dongles.

Now-days, with the improvements in software and documentation, the hardest part is finding the right dongle. What you order from EBay, and what you receive, can be two different things and only some of the dongles are suitable for use as VHF/UHF software defined radios.

So, I was pleased to see that at least one hobbyist electronics supplier has sought out and supplies a suitable device for SDR at a fair price :

Adafruit has available the USB dongle and “antenna” suitable for experimentation for $22.50, not far from the EBay (direct from China) price.

Click here to go directly to the product page: Software Defined Radio Receiver USB Stick – RTL2832 w/R820T

No, I didn’t receive a free evaluation unit and I don’t work for Adafruit … I’m just glad to see these useful devices available from a local company with an increased chance of you “Getting what you paid for.”

Adafruit also helpfully stock the adapter cables to convert the less common MCX antenna connector into the much more common BNC connector: MCX Jack to BNC RF Cable Adapter

An Amazing Moment in Space Weather – Massive Solar Eruption June 2011

November 29th, 2013 |

Author: Tomas NW7US

While many are talking about how Solar Cycle 24 is the weakest since the Maunder Minimum (the period starting in about 1645 and continuing to about 1715 when sunspots became exceedingly rare, as noted by solar observers of the time — see this Wiki entry), there are moments when activity on the Sun strongly increases, providing brief moments of excitement.

Here is a case in point, witnessed by the Solar Dynamics Observatory (SDO; see SDO Mission) on June 7, 2011, when the Sun unleashed a magnitude M2 (a medium-sized) solar flare with a spectacular coronal mass ejection (CME). The large cloud of particles mushroomed up and fell back down looking as if it covered an area almost half the solar surface.

SDO observed the flare’s peak at 1:41 AM ET. SDO recorded these images in extreme ultraviolet light that show a very large eruption of cool gas. It is somewhat unique because at many places in the eruption there seems to be even cooler material — at temperatures less than 80,000 K.

This video uses the full-resolution 4096 x 4096 pixel images at a one minute time cadence to provide the highest quality, finest detail version possible. The color is artificial, as the actual images are capturing Extreme Ultraviolet light.

It is interesting to compare the event in different wavelengths because they each see different temperatures of plasma.

Credit: NASA SDO / Goddard Space Flight Center

Video: http://g.nw7us.us/1aOjmgA – Massive Solar Eruption Close-up (2011-06-07 – NASA SDO)

Visit: SunSpotWatch.com

At 522,000,000 miles per watt, Voyager 1 might be the ultimate in QRP.

October 2nd, 2013 |

Author: Owen KF5CZO

At 522,000,000 miles per watt, Voyager could be the ultimate in QRP … if you have the right antenna.

For most HAMs the experience of seeing sub-one watt WSPR signals decoded from across the globe is enough of a thrill. However, the fine folks at the National Radio Astronomy Observatory have taken this a little further and used the Very Long Baseline Array radio telescope to precisely pinpoint the position of the Voyager 1 space probe.

While the layperson might see detecting the glimmer of 22 watts across the vastness of space miraculous, the amateur radio community can see this feat as the natural evolution and refinement of the technology and medium we know and love.

From nrao.edu:

Earlier this year, the National Science Foundation’s Very Long Baseline Array telescope turned its gaze to NASA’s famed Voyager 1 and captured an image of this iconic spacecraft’s faint radio signal. The Green Bank Telescope also detected Voyager’s signal, picking it out from the background radio noise in less than one second.

Astronomers using the National Science Foundation’s (NSF) Very Long Baseline Array (VLBA) and Green Bank Telescope (GBT) spotted the faint radio glow from NASA’s famed Voyager 1 spacecraft — the most distant man-made object.

According to NASA’s Jet Propulsion Laboratory (JPL), the VLBA imaged the signal from Voyager 1’s main transmitter after the spacecraft had already passed beyond the edge of the heliosphere, the bubble of charged particles from the Sun that surrounds our Solar System.

Using NASA’s Deep Space Network, JPL continually tracks Voyager and calculates its position on the sky, which is known as the ephemeris. Since the VLBA has the highest resolution, or ability to see fine detail, of any full-time astronomical instrument, NRAO astronomers believed they could locate Voyager’s ephemeris position with unprecedented precision. This is unrelated to Voyager’s distance from the Sun or position relative to the heliosphere.

The initial observations, which were made on February 21, placed Voyager very near, but not precisely at its predicted location. The difference was a few tenths of an arcsecond. An arcsecond is the apparent size of a penny as seen from 2.5 miles (4 kilometers) away. The second observations on June 1 produced similar results.

“It is possible that these observations are at the milliarcsecond [one-thousandth of an arcsecond] level, or better,” said NRAO scientist Walter Brisken, who led the observations with the VLBA. At 11.5 billion miles — Voyager’s approximate distance at the time of the initial observations — one milliarcsecond would be roughly 50 miles across.

Voyager’s main transmitter shines at a feeble 22 watts, which is comparable to a car-mounted police radio or — in visible light — a refrigerator light bulb. Though incredibly weak by the standards of modern wireless communications, Voyager’s signal is astoundingly bright when compared to most natural objects studied by radio telescopes.

“The ability to pinpoint the location of Voyager and other spacecraft is critical as we explore the inner Solar System and beyond,” said Brisken. “The NRAO’s VLBA has the capability to do this vital task with unprecedented precision.”

Voyager 1, which was launched in 1977, is now headed away from the Sun at a speed of about 38,000 miles per hour.

In a remarkably sensitive complementary observation, the NRAO’s Green Bank Telescope (GBT), which is the world’s largest fully steerable radio telescope, easily detected Voyager’s signal, picking it out from the background radio noise in less than one second.

“Voyager is the first man-made object to penetrate the interstellar medium, and we really want to be able to receive the data from this new frontier,” said NRAO scientist Toney Minter, who oversaw the Green Bank observations. “This information will provide many clues about how the interstellar medium behaves and how the Sun interacts with it.”

“NRAO’s instruments have the capability to provide the most accurate position information of distant spacecraft like Voyager,” said NRAO Director Tony Beasley. “The remarkable sensitivity of GBT and VLBA’s sharp vision are essential for discovery but also have unique capabilities that have enabled us to make this contact with one of humanity’s most ambitious missions of exploration.”

The VLBA is a system of radio antennas located across the United States from Hawaii to St. Croix. The antennas work together as a single telescope nearly 5,000 miles across, giving the VLBA its ability to see fine details. Only seven of the VLBA’s full complement of 10 antennas were used to make these observations.

The 100-meter GBT is located in the National Radio Quiet Zone and the West Virginia Radio Astronomy Zone, which protect the incredibly sensitive telescope from unwanted radio interference. The GBT observations were made by NRAO scientists Toney Minter and Frank Ghigo, and Green Bank Director Karen O’Neil.

Bdale KB0G Makes Stuff!

February 7th, 2013 |

Author: Bob KØNR

Last week, I had lunch with an old friend, Bdale Garbee (KB0G). Bdale and I had both worked at HP for a number of years and we have been involved in some common ham radio clubs and activities. I followed the test and measurement path with Agilent Technologies when that company was formed, while Bdale stayed with the HP computer business. He is a recognized industry expert in Unix, Linux and all things open source. It is always cool to catch up with him and find out what he has been doing. He recently took early retirement from HP…I am not sure what “retirement” means for Bdale but its not playing shuffleboard at the retirement home!

Coincidentally, a few days later, I came across this video from HamRadioNow of Bdale talking at the ARRL/TAPR Digital Communications Conference. In this talk, Bdale discusses the general theme of making stuff and the satisfaction that is derived from that activity. It is about an hour long so grab a cup of your favorite beverage and take a seat.

By the way, check out the other HamRadioNow videos, especially the videos of the DCC technical talks. Good stuff!

73, Bob K0NR

Easy Online Circuit Analysis

November 17th, 2012 |

Author: Bob KØNR

I was writing an electronics article today and started to do some circuit analysis by hand. It was a pretty simple circuit so I knew I could crank out the circuit analysis on paper but I started to think maybe there was a better way. I poked around the web and came across CircuitLab.com, a free, online circuit simulator. As … Continue reading …

Get your head in the cloud.

October 24th, 2012 |

Author: Owen KF5CZO

Even though my day job is completely centered around Information Technology I still miss changes and shifts in technology that happen practically under my nose. As much as I hear vendors speak about “The Cloud” I haven’t had much time to investigate and discover if this “new technology” is something I can put to use.

If you already know what “The Cloud” is then you can skip the following paragraph, otherwise please read on:

The easiest way to understand the cloud is to think of it as a utility, like electricity. When you plug a device into a wall outlet, electricity flows. You didn’t generate the electricity yourself. In fact, you probably have no idea where the electricity was generated. It’s just there when you want it. All you care about is that your device works. Cloud computing works on the same principle. Through an internet connection (the equivalent of an electrical outlet), you can access whatever applications, files, or data you have opted to store in the cloud–anytime, anywhere, from any device. How it gets to you and where it’s stored are not your concern (well, for most people they’re not).

By Rama Ramaswami, Dian Schaffhauser (http://campustechnology.com) 10/31/11

There is no end to the stream of interesting projects that are being developed “in the cloud” and its hard to keep track of them all. Some projects have turned into things that we’re all familiar with; Flickr, Facebook & Twitter are a few examples. Some appear and vanish like the proverbial “Flash in the pan” and, since you generally lose access once they run out of steam, it can be disappointing if you have invested any time in those applications.

I’ve collected a few cloud based applications/services here that might be of interest to the radio amateur and/or experimenter. They look like they should stick around for a while and have already reached a fair level of maturity:

circuits.io: Described as a free circuit editor in your browser, it is actually a lot more. You can not only design practically any kind of circuit using just a web browser, you can turn that circuit into a printed circuit board and then BUY that PCB board online. Several different technologies had to come together to make this into an effective tool. This tool is fairly new but is becoming very popular. Hopefully it will stick around and continue to mature into something great.

WebSDR: While arguably not a “cloud application” it does allow you listen to software defined radios, using a web browser, from anywhere you have internet access.
There are multiple sdr receivers located across the globe using a variety of receivers and antennas. Some are tuned to the HF bands while others cover VHF & UHF bands.
This is an invaluable free service provided by institutions and individuals at their own cost.

APRS.fi: The distributed network of Automatic Packet Reporting System stations, repeaters, clients and map servers could be considered to be “of the cloud” before the cloud even existed. With an APRS equipped radio you can log your position from a GPS, over the air & through another ARPS receiver. This is then sent out (usually) across the internet to other systems which in turn can map your location or update other APRS clients or radios. APRS has also been extended to include the ability to text message which is particularly useful in locations where cell phone SMS messages or email are not possible!

Echolink: Like APRS, Echolink links the Internet to amateur radio. However Echolink links the audio and PTT (push to talk) signals from a radio or software client to a radio in another physical location. If you’re stuck in a hotel room or another location without access to a radio you can still “get on the air” using an Echolink client on your Windows, Linux, iOS or Android computer & handheld device. Most Echolink connected stations are VHF/UHF but there are HF stations connected as well. Echolink is not designed to replace radio to radio communications but instead increases the connectivity of amateur radio operators and allows hams, who otherwise would not be able to operate, the pleasure of getting on the air.

As you can see, some of these “cloud apps” pre-date the idea of cloud computing by quite a while. Just another example of amateur radio folks being ahead of the curve without even realizing it.