Electromagnetic pollution: Lessons from the radio amateurs…
Recently, a study came out [PDF] that looked at the short-term health effects of electromagnetic radiation on humans (more readable version here). Subjects were exposed in 50 minute-long sessions to transmissions from ordinary GSM-transmitting stations, 3G transmitters (i.e. UMTS) and sometimes they were only told that a transmission would take place although the transmitter was switched off.
The individuals who classified themselves as being "sensitive" towards electromagnetic radiation reported flu-like symptoms and feelings of uneasiness even if the transmitter was switched off.
This reminds me of two stories related to one of my hobbies, Amateur Radio. Once a friend told me that he installed a new wire-antenna at his house, highly visible to his neighbours. On purpose, he did not connect the antenna to his transceiver and let the cable hang out of his window. He did not use the antenna for about three weeks, when during that time the first reports of feelings of "uneasiness" by his neighbours came it. After he told them that the antenna was in fact not operating yet, the critiques went silent.
I myself had some minor feedback about my antenna, when somebody complained that she could "feel the antenna radiating" and asked whether it was not a dangerous thing to use. Here as well, I had not used the antenna for weeks.
Even more funny are some mail-order catalogues, where one can buy next to products shielding you from the "evil" mobile phone radiation, other radiating products that are said to be "good" and shall increase your wellness, remove headaches and so on. Maybe I should also start selling "wellness radiation sessions"...
DL4CB @ SK0TM
 |
|
QSL card of SK0TM
|
Yesterday, I visited the Technical Museum in Stockholm. Next to the exhibitions, the museum has also its own amateur radio station, callsign SK0TM.
So, of course, I visited the station, entered the room and said like "Hello, I'm DL4CB". Immediately, Bengt (SM0YX) smiled and noted my callsign, stood up from his chair and said "Here, please sit down and use the station!". So did I.
I used their ICOM 756 transceiver, which was connected to a 5-element Yagi antenna. I made two contacts, the first one with a German station in Spain, where the temperatures were 30 degrees higher than here in Sweden. The second OM I talked to was in Rome in Italy. The audio quality was excellent, I would like to have such a Yagi antenna (and the space to put it up), too.
After one and a half hour, I left the station with 2 QSL cards (see picture) as a souvenir. Actually, we wanted to make a radio contact when I left the museum (I had brought my 2m/70cm handheld), but unfortunately that didn't work. We were not sure how to properly connect the 2m antenna to the transceiver. Bengt was only familiar with the shortwave station. At least the people at the busstop looked at me as if I was an alien when I tried to call him from outside :-) .
Emergeny Net Operations
The Salvation Army Team Emergency Radio Network (SATERN), that is currently coordinating emergency communications in the regions hit by hurricane Katrina, has put a guide online how to handle emergency operations on the radio. It is quite interesting because there are major differnces between ordinary (amateur) radio traffic and the emergency traffic. Especially when the load of health and welfare traffic increases a frequency can quickly become too crowded. In this case the guide proposes to open next to the main Command and Control net an additional "tactical" net that can handle some of the additional stations.
On Air Again
For the shortwave bands, I am using the GAP Eagle DX antenna. Its a vertical multibander for the 40, 20, 17, 15, 12 and 10 meter bands. Its about 6.5 meters long (21 ft) and for a shortwave antenna relatively small, although my neighbours may think differently about that.
Nevertheless, a few month ago, the cable clamp, which held the radials of the counterpoise together, burst and I had to find a new one. That was a bit tricky, since all parts of the antenna are from the US and therefore have the US measures. So most of the clamps I found in DIY stores were either too short in length or too thick. In the end I found a cable clamp, which was originally meant for a hosepipe. Today I mounted it together with the radials and the antenna is working again.
Next to that, I tried out my new tuner, the MFJ-941 E. I got it used for a reasonable price. To test for the limits of the box, I tried to match a 1 meter long aluminium pipe for 40 meters and it worked! Ok, I did not hear anything on the frequency, but at least the SWR was all right.
After that, I attached my "frying pan" antenna to it, which consists of a pan and a 1.75 meter long radiator. I built it using the instructions by DL7PE (sorry, this website is only in German so far). Beneath the pan is a pancake coil, specially designed for 14 MHz. Without matching, it had a SWR of 2:1, with the tuner, it moved to 1:1. I could hear a lot of stations, a bit weaker in comparison to the GAP Eagle, but when considering the small size of this pan antenna it performs pretty good actually. However, its really difficult to tune without a tuner, although DL7PE says that it should work without one.
“Prototypical Nerds”
Wired features an article about amateur radio (also called ham radio), which is also my hobby.
Hams are characterized as being "the planet's prototypical nerds". Next to that, the article mentions the Hamvention in Dayton. In Europe, a similar fair is the "Ham Radio" in Friedrichshafen, Germany. I've been there two or three times already and its really nice to catch up with the latest developments and experience the so-called ham spirit.
Antennas go undercover
Deutsche Welle today reports (The Register has it also) that a number of companies have developed undercover antennas, mainly for the mobile phone sector. Those range from antennas looking like trees to an antenna mast disguised as a crucifix.
This story reminds me of an article in one of the last CQ DLs (the German amateur radio club magazine), where a HAM reported that since he attached a small (Danish) flag on top of his antenna, there were suddenly no more complaints about "strange" TV and radio interferences. Everybody is now seeing his antenna as an ordinary flagstaff and all the problems are gone.
UMTS monitoring vehicle
Today, I spotted an interesting looking car at a McDonald's restaurant near Neuwied. It was an ordinary looking VW Sharan, but what caught my attention were the 7 antennas on its roof. I first thought that these were normal GSM antennas and I was wondering why you would need 7 of them, but lying on the front passenger's seat were maps of the Neuwied/Koblenz area that showed measurements of the UMTS coverage. So these antennas were UMTS antennas (6 of them), the last one was an additional GPS antenna. Also on the front passenger's seat was a flatscreen monitor, unfortunately, turned off. In the back of the car were all kinds of technical things like telephone equipment in 19" racks. I would have liked to talk to the driver, however, I could not see him. Maybe he was enjoying his (or her?) meal.
“@”-sign finally in morse code alphabet
The International Telecommuication Union finally introduced the "@"-sign in the morse code alphabet. The "@" will be then .--.-. from May on. The morse code itself celebrates its 160 year anniversary these days.
But is telegraphy still used today? Yes, in some countries you still need to take a morse code exam to get an amateur radio licence. However, many countries have abolished this requirement. I also had to take this exam when I did my amateur radio licence exam, but only with a reduced speed of only 25 letters per minute. The speed in real life is much higher than this and starts with 60-80 letters per minute.
If you want to have a QSO (for the non-HAMS, this is a conversation via the radio) in such a high speed there are also several computer programmes available that you can connect to your transceiver. This website links to several of these programmes.