Are you isolated?

There are many times in amateur radio where you want to “isolate” two pieces of equipment or avoid “ground loops.” For example, when connecting a computer to a rig to do digital modes, you should isolate the signals so that there’s no direct connection between the rig and the radio.

What does it really mean to be isolated, though? And, for that matter, what is “ground”?

You can learn what these  terms actually mean and when and why you need isolation if you view the webinar Fundamentals of Signal and Power Isolation. Here’s how they describe the webinar:

This Fundamentals course will briefly look at power isolation (often required in conjunction with signal isolation) and then focus on signal isolation techniques. It will look why it is needed, where it is needed, the relative attributes of techniques for implementing it, and other considerations.

From my Twitter feed: SDR rx, cool projects, JT-65

sparky73dx's avatar

roteno's avatar
Victor Laynez @roteno

July Call for Projects! Send links/pictures of your cool projects. One of mine: @eevblog uCurrent for my bench pic.twitter.com/ps9giFTB7x

 

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Bill WØSUN ? @w0sun

“JT65 – Easy as Pie!” feedly.com/k/1e6pEHI #hamr #Hamradio

Amateur radio in the news: Art Bell, Vietnam vet, amateur radio “Olympics”

Art Bell to make comeback with Sirius show about the paranormal. Art Bell, W6OBB, radio’s master of the paranormal and outward edges of science, will return to the microphone on Sept. 16 with a new nighttime show on Sirius XM Radio. Bell was one of radio’s top syndicated voices in the 1990s before walking away from his nightly show in 2002 due to family issues. He worked occasionally after that but hasn’t been on the air since Halloween 2010.

Learning on the fly: Kent’s Sealfon recalls the skills he learned in Vietnam after Army training. Life rarely goes as planned, and even the best training doesn’t prepare us for everything. If there’s one lesson Michael Sealfon learned during his yearlong tour in the Vietnam War, and the 40 years since, it’s that.

Operators prepare to host amateur ham radio ‘Olympics’. The World Championship of amateur ham radio is coming to Massachusetts next year, and local ham-radio operators were helping prepare for it by testing sites around the region this past weekend. “This is big international stuff, and Massachusetts is the one that’s hosting it,” said local ham radio operator Bob Reif. He helped set up a radio tower in Heald Street Orchard Friday morning to test the site for the competition. “It’s the Olympics of amateur radio.”

Taking some of my own medicine

astron_rs35m

I took a dose of my own medicine and performed a little preventive maintenance on my Astron RS-35M power supply.

Last week, I wrote a blog post on preventive maintenance for one of my writing clients.

Afterwards, I decided to take some of my own medicine and do a little preventive maintenance around the shack. I started with the Astron RS-35M, which provides the DC power that runs HF transceiver and my VHF/UHF transceiver in my shack. I had started noticing a few little things, such as the voltage adjustment being a little fussy, that I wanted to correct before the supply failed on me.

After removing the cover, I vacuumed all the dust out of the supply. The RS-35M wasn’t very dirty, but even so, getting the dirt out of a piece of equipment is probably the first thing you’ll want to do when performing preventive maintenance. Dirt impedes air flow. That can lead to higher operating temperatures, and as the lab manager that I interviewed for my blog post said, “Heat kills.”

Not only should you vacuum any dust out of a cabinet, you should also clean the fan filters, if your gear has them. Dusty filters prevent air from flowing smoothly through equipment, and that means the fans don’t cool as well as they should.

Once that was done, I did a visual inspection. One thing that you want to look for are components that look like they’re getting too hot. Another thing to look for is evidence of arcing. Whatever is causing the overheating or arcing will eventually cause a unit to fail. Fortunately, I found neither.

Next, I checked to see that the components mounted to the enclosure were securely screwed down. In the RS-35M, the transformer, the bridge rectifier, and an electrolytic are mounted to the enclosure. Oddly enough, the bridge rectifier was quite loose, so I tightened it down. Also loose were the output terminals. I tightened these down as well.

Finally, I squirted a little cleaner and lube into the voltage adjustment pot and worked it back and forth. That seemed to do the job. That pot now works smoothly and cleanly.

I put the cover back on, reconnected the power cable, and got back to making QSOs. It should be good for another couple of years.

Notes from the ARRL Board Meeting, July 19-20, 2013

ARRLI haven’t gotten the full minutes yet from the recent ARRL board meeting, but there’s a news story about the meeting on the ARRL website. Some interesting things were discussed:

  • ARRL to spend big bucks on Logbook of the World. The board voted to spend $75,000 on outside professional services to improve LoTW’s database. The Board also okayed the hiring of a full-time Headquarters staff member with “strong IT development and architectural skills” to address LoTW improvements. That seems like an awful lot of money to me.
  • ARRL will petition FCC to get rid of symbol rate references. Instead of specifying symbol rates in Part 97. 307(f) , the petition would ask the FCC “to apply to all amateur data emissions below 29.7 MHz the existing bandwidth limit, per §97.303(h), of 2.8 kHz.” I like this idea a lot. It will give hams the incentive to experiment with new digital modes.
  • New training materials.  The article notes that the Board “directed Headquarters staff to investigate the feasibility, benefits and costs of preparing license training materials designed for shorter course sessions.” Uhhhh, I’ve had those materials for many years now. Not only that, the PDF version is FREE! 

Have a vision

Yesterday, while reading the book Language Intelligence: Lessons on persuasion from Jesus, Shakespeare, Lincoln, and Lady GaGa, they used as an example Bill Clinton’s acceptance speech at the 1992 Democratic convention. Here’s an excerpt:

Of all the things that George Bush has ever said that I disagree with, perhaps the thing that bothers me most is how he derides and degrades the American tradition of seeing and seeking a better future. He mocks it as the “vision thing.”

But just remember what the Scripture says: “Where there is no vision, the people perish.”

I hope nobody in this great hall tonight, or in our beloved country has to go through tomorrow without a vision. I hope no one ever tries to raise a child without a vision. I hope nobody ever starts a business or plants a crop in the ground without a vision. For where there is no vision, the people perish.

One of the reasons we have so many children in so much trouble in so many places in this nation is because they have seen so little opportunity, so little responsibility, so little loving, caring community, that they literally cannot imagine the life we are calling them to lead.

And so I say again: Where there is no vision, America will perish.

Of course, amateur radio is just a hobby, but doing great things always starts with a vision. If you have a vision for what you want to do in amateur radio, there’s more of a chance that you’ll do something fun and exciting. That could be providing emergency communications or building a software-defined radio or even writing amateur radio license study guides. It might seem that encouraging you to have a vision about a hobby is taking it a bit far, but seriously, you will have more fun with amateur radio if you think about what drew you to the hobby in the first place and then set some goals. Doing so will keep you engaged and help you do cool things.

RSGB general manager on the future of amateur radio

RSGB General Manager, Graham Coomber G0NBI, recently expounded on his vision for the future of Amateur Radio at the AMSAT-UK International Space Colloquium on Sunday, July 21, 2013. The video is now available in the Film Archive section of the BATC site.

You can watch the video at http://www.batc.tv/ by doing the following:

  • Click on the `Film Archive’ icon
  • Select `AMSAT-UK 2013? from the Category drop down menu
  • Click `Select Category’
  • Select the video ‘AMSAT2013 09 RSGB’
  • Click on `Select Stream’
  • Click the play icon `>’ on the player
  • Clicking on the icon to the left of the player volume control will give you full screen display.

You can also download the video file to your PC by clicking on the `Click Here’ link under the player.

G0NBI has some interesting observations on the rising median age of amateur radio operators, how people get into amateur radio, and the role of experimentation in amateur radio. The statistics he quotes are all for the UK. It would be interesting to compare those to statistics for the US (if there are any such statistics).

Amateur radio in the news: SkyWarn, making vacuum tubes again, Friedrichshafen

Chris, KE5ZRT, is president of the Panhandle ARC and a SkyWarn storm spotter

Chris, KE5ZRT, is president of the Panhandle ARC and a SkyWarn storm spotter

Volunteer storm spotters essential to Weather Service. The haunting companions to tornadoes and major thunderstorms make children cry, grown men run into basements and auto dealership owners cringe. But some people embrace the danger and even seek it out for entertainment. Among this group are Skywarn storm spotters, volunteers who work with the National Weather Service to track and report storms from the front lines.

Making tubes again. Western Electric has been resurrected, and its headquarters are in Rossville, GA. A once-vacant bank building was adorned about three weeks ago with distinctive red-lettered “Western Electric” signs on its east and west sides. The Rossville operation will make vacuum tubes mainly for use in high-end audio components. “It’s a lost art,” company president Charles G. Whitener Jr. said.

Ham radio — a pastime not just in the past. With today’s advanced wireless technology, amateur radio might have become obsolete. Yet, it hasn’t. Did you know the first “chat room” was invented by ham radio operators? They communicated across the continents during wartime, and played chess all hours of the day and night. And amateur radio invented social networking. Amateurs are viewed as public servants and a national resource. It doesn’t look like these guys are going away anytime soon.

Ham operators’ paradise at Friedrichshafen’s flea market. Over a week ago I attended the Ham Radio show in Friedrichshafen, Germany. This is the biggest ham radio show in Europe and has the usual big-convention mix of commercial exhibitors, national society exhibits, conference-style forums, and… a flea market.

From my Twitter feed: Rigs for Ethiopia, Sun’s bizarre behavior, mobile apps

 

RigolHam's avatarSteve Barfield@RigolHam
Yasme Foundation Funds Transceivers for New Ethiopian Hams | @arrl amateur radio goo.gl/IR7wU

 

RadioGeek's avatarKKØHF @RadioGeek
LA Times – Sun’s bizarre behavior: Weakest solar cycle in 100 years touch.latimes.com/#story/la-sci-

 

HamTubeJp's avatarHamTubeJp @HamTubeJp
Mobile Apps for Ham Radio: Mobile Apps for Ham Radio This video will… goo.gl/fb/FVJ18 #YoutubeHam3 #hamr

Amateur radio in the news: Bob Heil K9EID, HSMM-Mesh wins award, teens help win WWII

Bob_HeilThe sound of Heil. He saved tours of the Grateful Dead and The Who, and is credited with the birth of modern live sound by revolutionizing the equipment that bands used, starting in the 1960s. In fact, Bob Heil, ham radio operator, sound equipment inventor, and founder of Heil Sound, is the only manufacturer to have equipment on display at the Rock and Roll Hall of Fame.

Ham ops win iAEM-Global technology & innovation award. Broadband HamnetTM, developed by amateur radio operators to provide a high speed digital wireless communications mesh network, has won the IAEM-Global Technology & Innovation Award, Division 2.. The firmware is available at no charge via the project website at www.hsmm-mesh.org.

The teenage radio enthusiasts who helped win World War II. There were about 1,500 so-called voluntary interceptors during WWII – civilians helping to intercept secret Nazi code. To mark the centenary of the Radio Society of Great Britain, one of its members recalls how the amateur organisation played a key role in a covert operation to safeguard the country’s independence.