More ham radio on Twitter and G+

Three more things I found while Twittering and using Google+.

Stay Connected to Your Broadband – an Improved ADSL Filter. I have a DSL line here, and have never had any RFI problems. In Great Britain, however, their broadband lines  seem to be susceptible. This 2010 article shows you how to build a filter that will fix that right up.

Learn circuits and electronics from MIT. The Massachusetts Institute of Technology is putting a lot of courses online, and you can take them for free!  This course, Circuits and Electronics, is the core course for all undergraduate electrical engineering (EE) and electrical engineering and computer science (EECS) students. Before you jump into this, realize that they say it will require about ten hours per week, and you need to know some basic calculus and linear algebra. This is an academic class, after all.

Open Hardware Journal. From the first page:

Open Hardware means sharing the design of physical or electronic objects with the public, similarly to Open Source software. The right to use, modify, redistribute, and manufacture, commercially or as a non-profit, is granted to everyone without any royalty or fee. Thus, Open Hardware designers hope to enrich society by developing a library of designs for useful objects that everyone can make, use, and improve.

The second issue features an article on the TAPR’s High-Performance Software-Defined Radio (HPSDR) project, which now includes over a dozen building blocks that can be used to assemble a high-grade 100 kHz to 55 MHz software-defined radio.

Changes to Euro EMC Directive Could Include Ham Kits

On the International Amateur Radio Union (IARU), Region 1 website, Thilo Kootz, DL9KCE, Chairman EUROCOM Working Group, writes:

As part of the NEW LEGISLATIVE FRAMEWORK (NLF) ALIGNMENT PACKAGE the European Commission is reworking some directives. One of the affected directives is the EMC directive including some major changes. Most of them are neutral or even good from an amateur radio operators perspective. However there is one slight change pickaback carried, which very much affects us.

In detail:

The definition of the term ‘electromagnetic disturbance’ will include the wanted signal of a radio as a possible source. This is not in line with the radio regulation of the International Telecommunication Union (ITU) and not in line with the vocabulary of the International Electrotechnical Committee (IEC).

IARU Region 1 will respond to it with a letter soon.

However we strongly suggest, that you contact your local MEPs and tell them about this change in the EMCD, that is neither in line with the reasoning of the New Legislative Framework, nor does it help to improve protection of radio services or equipment.

The full text of Directive 1999/5/EC can be found here.

What always interests me in these cases is why these changes are being proposed. Do ham radio kits really generate that much EMI, or is some commercial interest behind this?

Smart Meters Causing RFI

SmartGridElectronics.Net is reporting that some smart meters are causing RFI. In an article published today, they say:

The smart meters that Central Maine Power Company (CMP) is installing throughout its territory pursuant to Commission approval are causing radio frequency interference with some customers’ electrical appliances, personal computers, and communications devices. To date, over 200 customers have contacted CMP about problems with a variety of appliances and devices including phones (cell, cordless, and landline), answering machines, Internet routers and wifi, personal computers, TVs, garage doors, fire alarms, clocks and even electric pet fences. The most common problem is interference with wireless internet routers, because they use similar radio frequencies. The problems can often be resolved by simply changing a setting on the device. Other concerns include malfunctioning phones, Internet routers crashing or freezing, damage to computer hard drives, static and clicking sounds on communication and computer gear, inability to stream Netflix, failure of TV remote, and other appliance malfunctions.

Fortunately, they’re not using BPL for this project. They’re using some kind of wireless networking in the 2.5 GHz band. Even so, it makes you wonder if anyone ever did any EMI/RFI testing on these devices.

ZDNet Australia has also published an article on this situation.

Fun With Antennas

I got back on the shortwave bands in August, putting up a 20m dipole. While 20m is fun, I’ve wanted to try out some of the other bands, too. When I was a kid, I used to work 40m a lot, especially late at night. So, I decided to put up a 40m dipole.

I’m lucky in that I have a number of trees to use as an antenna support. While there’s not quite enough space to string an 80m dipole, I guesstimated that a 40m antenna would fit quite nicely.

So, I mail-ordered a bunch of stuff from RadioWorks. The stuff was very nice quality, but I was a little miffed that some of the prices were higher than advertised. I understand that prices can change, but they really should make an effort to update the ads they run in QST and other magazines. It looks to me like they haven’t been updated for more than a year.

At any rate, I got all the parts, and in rummaging through my junk boxes came across a 1:1 balun that someone had given me. I built the dipole using that balun instead of the RadioWorks balun that I’d just purchased. The antenna wire I bought is that fancy, flexible stuff. As advertised, it was very easy to work with, and looks to be quite strong, too. I also put together a 100′ RG 59 cable.

So, Saturday afternoon I get out into the backyard and string it up. Using the Autek VA1 antenna analyzer, I adjust the length for the lowest SWR I can manage. Oddly, it doesn’t seem as though I can get it much lower than about 1.5:1, but that’s OK. It should still work. (More about this later.)

Finally, I get the thing up in the air, and hurry down to the shack to give it the smoke test. I check the SWR again with the Autek, and it looks pretty good. I connect it to my rig–an Icom IC-735–and tune around for a clear frequency. Finally, I put the power to it, and adjust the internal SWR meter.

Wow. The SWR looks even better than it did with the Autek. I send out a few Vs, and then my wife comes rushing downstairs. “”You’re coming in loud and clear,”” she says, “”over the computer speakers! AND you’re making the garage door go up and down, to boot!””

Yipes. I didn’t have this problem with the 20m dipole at all, and I thought a balun was supposed to help reduce RFI.

At this point, it was almost dinnertime, so I just pulled the plug on the rig and decided to sleep on things. It’s too bad, too, because I had wanted to make a few contacts in the CW Sweepstakes Contest. Oh well.