AMSAT MPPT Goes To Infinity And Beyond

November 27, 2017 by Lauren Faris 19 Comments

AMSAT, the Radio Amateur Satellite Corporation, joined forces with students from Rochester Institute of Technology to create a MPPT attached to a Fox-1B CubeSat. It successfully launched into orbit on November 18th strapped to the back of a Delta II rocket. This analog MPPT, or Maximum Power Point Tracker, is used for optimizing the draw of a power cell in correspondence to the output of solar panels on the 10cm x 10cm satellite. In a nutshell, this works by matching the voltage of the two together. If you haven’t gotten a chance to play around with one of these first hand, Hackaday’s own [Elliot Williams] wrote up a thorough explanation of the glorious MPPT’s efficiency.

This little guy is currently hurtling along in an orbit every 90 minutes. During each of these elliptical trajectories, the satellite undergoes brutal heating and cooling cycles. The team calculated that this package will undergo a total of 29,200 orbits around Earth during its 5 year mission. This means that there are 29,200 tests for it to crack — quite literally — under pressure. To add another level of difficulty, the undergrad team didn’t have funding for automated board assembly. This meant that they had to hand solder over 400 micro components onto this board, adding additional human error to be accounted for in the likelihood of a failure. But so far, this puppy is going strong. This truly shows the struggles that can be overcome with a little elbow grease, hard work, and plain ‘ole good engineering.

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Raspberry Pi Learns Slow Morse Code

November 13, 2017 by Al Williams 11 Comments

It wasn’t long ago that you needed to know Morse code to be a ham radio operator. That requirement has gone in most places, but code is still useful and many hams use it, especially hams that like to hack. Now, hams are using the Raspberry Pi to receive highly readable Morse code using very low power. The software is QrssPiG and it can process audio or use a cheap SDR dongle.

There are a few reasons code performs better than voice and many other modes. First, building transmitters for Morse is very simple. In addition, Morse code is highly readable, even under poor conditions. This is partly because it is extremely narrow bandwidth and partly because your brain is an amazing signal processor.

Like most communication methods, the slower you go the easier it is to get a signal through. In ham radio parlance, QRS means “send slower”, so QRSS has come to mean mean “send very slowly”. So hams are using very slow code, and listening for it using computerized methods. Because the data rate is so slow, the computer has time to do extreme methods to recover the signal — essentially, it can employ an extremely narrow filter. Having a QRSS signal detected around the world from a transmitter running much less than a watt is quite common. You can see a video introduction to the mode from [K6BFA] and [KI4WKZ], below.

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Satellite Tracking With Friends

September 12, 2017 by Lewin Day 3 Comments

If you’re in the mood to track satellites, it’s a relatively simple task to look up one of a multitude of websites that can give you a list of satellites visible from your location. However, if you’re interested in using satellites to communicate with far-flung friends, you might be interested in this multi-point satellite tracker.

[Stephen Downward VA1QLE] developed the tracker to make it easier to figure out which satellites would be simultaneously visible to people at different locations on the Earth’s surface. This is useful for amateur radio, as signals can be passed through satellites with ham gear onboard (such as NO-44), or users can even chat over defunct military satellites.

[Stephen] claims the algorithm is inefficient, but calculations are made in a matter of a few seconds, so we’re not complaining. While it was originally designed for just two stations, it works with a near-infinite number of points. [Stephen] recommends verifying the tracks with another tool once calculated to ensure accuracy. The tool is accessible here, and the code is up on GitHub for your perusal.

Perhaps now you need a cost-effective satellite-tracking antenna? [Paul] has you covered.

A Ham Radio Go-Box Packed With Functionality

September 9, 2017 by Dan Maloney 16 Comments

“When all else fails, there’s ham radio.” With Hurricane Harvey just wrapping up, and Irma queued up to clobber Florida this weekend, hams are gearing up to pitch in with disaster communications for areas that won’t have any communications infrastructure left. And the perfect thing for the ham on the go is this ham shack in a box.

Go-boxes, as they are known, have been a staple of amateur radio field operations for as long as there have been hams. The go-box that [Fuzz (KC3JGB)] came up with is absolutely packed with goodies that would make it a perfect EmComm platform. The video tour below is all we have to go on, but we can see a tri-band transceiver, an RTL-SDR dongle and a Raspberry Pi with a TFT screen for tracking satellites. The Pi and SDR might also be part of a NOAA satellite receiver like the one [Fuzz] describes in a separate video; such a setup would be very valuable in natural disaster responses. Everything is powered by a 12-volt battery which can be charged from a small solar panel.

[Fuzz] is ready for action, and while we genuinely hope he and other hams won’t be needed in Florida, it doesn’t seem likely at this point. You can read more about the public service face of ham radio, or about an even more capable go-box.

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Amateur Radio Just Isn’t Exciting

August 1, 2017 by Jenny List 171 Comments

As ARRL president, [Rick Roderick, K5UR] spends a significant amount of time proselytising the hobby. He has a standard talk about amateur radio that involves tales gleaned from his many decades as a licence holder, and features QSL cards from rare DX contacts to show how radio amateurs talk all over the world.

He’s delivered this talk countless times, and is used to a good reception from audiences impressed with what can be done with radio. But when he delivered it to a group of young people, as Southgate ARC reports, he was surprised to see a lack of interest from his audience, to whom DX or contesting just don’t cut it when they have grown up with the pervasive Internet. Writing in the 2016 ARRL Annual Report, he said:

“Change generally doesn’t come easy to us. But when I looked out at that group of young faces and saw their disinterest in traditional ham pursuits, I realized that I had to change. We have to change. It won’t come easy, but it’s essential that we get to work on it now.”

If you were to profile a typical group of radio amateurs, it would not be difficult to see why [K5UR] found himself in this position. It might be an unflattering portrait for some amateurs, but it’s fair to say that amateur radio is a hobby pursued predominantly by older more well-off men with the means to spend thousands of dollars on commercial radios. It is also fair to say that this is hardly a prospect that would energize all but the most dedicated of youthful radio enthusiasts. This is not a new phenomenon, where this is being written it was definitely the case back in the days when they were issuing G7 callsigns, for instance.

Were Hackaday to find ourselves in the position of advising the ARRL on such matters, we’d probably suggest a return to the roots of amateur radio, a time in the early 20th century when it was the technology that mattered rather than the collecting of DXCC entities or grid squares, and an amateur had first to build their own equipment rather than simply order a shiny radio before they could make a contact. Give a room full of kids a kit-building session, have them make a little radio. And lobby for construction to be an integral part of the licensing process, it is very sad indeed that where this is being written at least, the lowest tier of amateur radio licence precludes home-made radio equipment. Given all that, why should it be a surprise that for kids, amateur radio just isn’t exciting?

We’ve shown you some fantastic amateur radio builds over the years. If you have a youngster with an interest in radio, show them a BitX transceiver, or the world of QRP.

Header image: enixii. [CC BY 2.0]. We hope these snoozing kids aren’t in the middle of a lecture on amateur radio.

Heathkit’s New RF Meter: Who Is It For?

June 23, 2017 by Al Williams 25 Comments

Electronic hackers and ham radio operators of a certain age have a soft spot for the Heathkit brand. Maybe that’s why we had a rush of nostalgia when we saw the Heathkit site had a new product. You may recall that Heathkit had gone the way of the dodo until a few years ago when the brand started to resurface. Their latest kit is a precision RF meter which is available on preorder.

Before there were websites and hacker spaces and all the modern push to “do it yourself,” Heathkit was teaching people electronics through kit building. Sure, they were known for ham radio and test equipment, but many people built stereos (hi-fi), TVs, radio control gear, computers, and even robots. All with manuals that are hard to imagine if you haven’t seen one. They were world-class.

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Long Range Wireless Internet

June 20, 2017 by Bryan Cockfield 46 Comments

While most of you reading this have broadband in your home, there are still vast areas with little access to the Internet. Ham radio operator [emmynet] found himself in just such a situation recently, and needed to get a wireless connection over 1 km from his home. WiFi wouldn’t get the job done, so he turned to a 433 MHz serial link instead. (Alternate link)

[emmynet] used an inexpensive telemetry kit that operates in a frequency that travels long distances much more easily than WiFi can travel. The key here isn’t in the hardware, however, but in the software. He went old-school, implemending peer-to-peer TCP/IP connection using SLIP — serial line Internet protocol. All of the commands to set up the link are available on his project page. With higher gain antennas than came with the telemetry kit, a range much greater than 1 km could be achieved as well.

[Editor’s note: This is how we all got Internet, over phone lines, back in the early Nineties. Also, you kids get off my lawn! But also, seriously, SLIP is a good tool to have in your toolbox, especially for low-power devices where WiFi would burn up your batteries.]

While it didn’t suit [emmynet]’s needs, it is possible to achieve extremely long range with WiFi itself. However this generally requires directional antennas with very high gain and might not be as reliable as a lower-frequency connection. On the other hand, a WiFi link will (in theory) get a greater throughput, so it all depends on what your needs are. Also, be aware that using these frequencies outside of their intended use might require an amateur radio license.

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