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Posts Tagged ‘Electronics’

Arduino Frequency Display For Kenwood TS-520S HF Ham Radio PART 2

March 19th, 2014 |

This is (PART 2A & 2B) of the project “Arduino Frequency Display For a Kenwood TS-520S HF Ham Radio”. This part covers small signal amplification of a 0.2 volt peak-to-peak 5.5 MHz signal into Schmitt triggered NAND gate for cleanup before being cleanly counted by the Arduino. All parts: (PART 4), (PART 3), (PART 2), (PART 1)

(PART 2A)

(PART 2B)

Here are the datasheets for the two chips I used in (PART 2)

74HCT132 Quad 2-input NAND Schmitt trigger (PDF)
NE592 video Amplifier (PDF)

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Intermediate is go

March 14th, 2014 |

Author: Dan MØTGN

We have started another intermediate class both in class and distance learning. This course is primarily run on Edmodo. We have run a couple of classes on Edmodo and we think we have the concept correct now. So we have our weekly quizzes set and our 3 week homework assignments all loaded and ready to go.

In class students are also welcomed to join the distance learning students so missing a lesson is no longer such an issue.

Over the coming weeks I will be creating some companion videos showcasing the practical elements of our in lesson activities.

So far we have 5 in class and around 30 distance learning joining us for the next 10 weeks.

Bloody Proprietary Connectors

February 14th, 2014 |

Author: Bob KØNR

I came across this video rant by David L. Jones on the EEVblog concerning proprietary cables on consumer devices. I agree with him completely. Warning: some language not suitable for kids.

Unfortunately, if you look at ham radio gear, we are in even worse shape than the consumer market. Heck, even the freaking microphone connectors are unique to each manufacturer.

Foxx 3 TRX build

December 2nd, 2013 |

Author: Dan MØTGN

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.