RADIO HABANA CUBA
DXERS UNLIMITED
WEEKEND EDITION
SATURDAY, AUGUST 18, 2001
By Arnie Coro CO2KKSend your comments, questions and ideas to: arnie@radiohc.org
Hi, amigos RADIO-AFICIONADOS! Welcome to another edition of Dxers Unlimited, coming to you from Havana. I am Arnie Coro, radio amateur CO2KK, and here are today's headlines: Radio noise... is the worst enemy of the radio enthusiast... radio frequency energy that interferes with the reception of wanted signals can come from many different sources, which sometimes are really very difficult to find and then eliminate them... Radio noise like this example you will hear now makes reception difficult or even impossible!!
That was radio frequency noise generated by a nearby TV set's horizontal output circuit and high voltage generator!!! That's why reception of radio signals is becoming so difficult in our cities, and even those that happen to live way out in the countryside, have to deal with noise generating devices that have become part of our daily life...
Not even those that generate their own green electricity from solar panels or small hydroelectric units are exempt from radio noise!!! That's why today I'll dedicate most of Dxers Unlimited's airtime to talk about radio noise and thanks to the kind contribution of my good friend and long time faithful listener of this show, Bruce Atchinson, VE6XTC a Canadian radio amateur operator and short wave listener, his article is entitled "Light emitting diode lamps intended to replace regular lightbulbs, both incandescent and compact fluorescent." Margarita Delgado is my sound engineer and producer, I am Arnie Coro in Havana.
BuZZZ....
That was another example of radio noise.... this one generated by a nearby fluorescent lamp fixture!!! You are listening to the weekend edition of Dxers Unlimited, and for your information arnie@radiohc.org is the e-mail address to which you can send your signal reports and comments about the show, as well as your radio hobby-related questions for Dxers Unlimited's popular section "You have questions and Arnie answers them." Via AIR MAIL, a postcard will do, Send it to Arnie Coro, Radio Havana Cuba, Havana, Cuba...
Now, as requested by many Dxers Unlimited's listeners, here is the article about the new ZERO RADIO NOISE Light Emitting Diode lamps, written by VE6XTC, Bruce Atchinson, here is how he started his e-mail to me, and I quote:
Dear Arnie, I wrote this article for a local newspaper. I believe this is a solution to those compact fluorescent bulbs which make so much noise. Here is what I wrote... And Bruce's article starts right here...
LIGHT-EMITTING DIODE LAMPS
by Bruce Atchinson, VE6XTCNow that we are officially in the 21st century, isn't it high time for a new kind of lighting system? The incandescent bulb has been around since Thomas Edison invented it in 1879.
Though fluorescent lamps consume about 70% less power than incandescent lights, they also rely upon heating filaments to make them glow. AND both fluorescent and especially the new electronic compact fluorescent lamps are very powerful radio noise generators that produce a lot of interference to radio reception.
A new energy-efficient light source will soon be available which uses silicon, the same material that transistors and integrated circuits are made from. Since the late seventies, we have had light-emitting diodes, abbreviated as "LEDs," as indicators on equipment and as digital read-outs on clocks and calculators. Now, a white color LED has been developed and it is bright enough to be used as a light source. A new chemical composition made possible this new technological breakthrough, because so far, light-emitting diodes' colors only included a very limited range, with red, yellow and green the more typical, and blue available less frequently. The most popular light-emitting diodes used in electronics are the red and green ones, with the yellow-colored less frequently used by designers.
Nowdays several suppliers are marketing replacements for various types of incandescent bulbs that use LED's. Though the light isn't exactly a pure white color, improvements are constantly being made to the semiconductor materials. The LED arrays only use a fraction of the wattage that conventional lamps use and yet they provide the same amount of illumination.
They are also extremely rugged from a mechanical point of view -- no filaments to open up, no glass to break ... One example of this is their LED 60 watt bulb replacement. According to a catalog available from one of the suppliers, the LED array consumes only 5 watts of power but produces the same light level as a 60 watt lamp.
That is a 12-to-1 ratio of actual energy saving, something really outstanding by all standards!!! And, as expected it generates a lot less heat than the incandescent lamp or even a compact fluorescent electronic lamp.
This discrepancy in power consumption is due to the fact that the tungsten filament in the standard incandescent lamp produces 90% of its output as heat. LEDs convert electricity directly into light, so losses are at a minimum.
Light-emitting diode direct flashlight bulb replacements are now also available. These are highly useful in various situations, such as camping or cave exploring, where incandescent lamps give the batteries a real workout. Other types of LED arrays are also available, including flood lamps and car taillights and headlights. Exciting developments and new applications of LEDs will soon be common in everyday life.
Some cities are currently looking into replacing incandescent traffic lights with LEDs. A variety of manufacturers now make LEDs that emit ultraviolet light. These are ideal for mineralogists needing a portable UV light source. Laser LEDs already are being used in cartography, architecture, lecture halls, and other applications.
Anywhere a light is needed, these versatile semiconductor devices will soon be found, helping to reduce electricity demand.
One nice thing about these LED arrays is that they can last up to 100,000 hours before needing to be replaced, and that's TEN times longer life than even the best-quality compact electronic fluorescent energy-saving lightbulbs!
With the alarming rise of the cost of electric power worldwide, it makes perfect sense to buy these penny-pinching long-lasting LED lamps. Though they seem expensive (a 60 watt bulb replacement costing now about $50 US each), these energy-efficient lights save money in the long run, and prices are expected to go down soon, too.
The new LED lamps also can decrease greenhouse gas emissions by lessening the energy demands from homes and businesses.
AND OF COURSE, what is most important for us radio hobbyists, LED lamps do not generate any kind of radio frequency noise whatsoever!
Again, just in case we had QSB on our signal...
LED lamps DO NOT generate any kind of radio frequency noise whatsoever! As a matter of fact, it would be an excellent idea, as soon as they are cheaper, to replace all the lamps near your radios with the new light-emitting diode ones!
Thank you very much, Bruce Atchinson from Alberta, Canada for this nice article, and after you sent it to me, I connected an array of 8 red light-emitting diodes of the type used as panel lamps, fed them from a battery and YES, the LED lamp works very well indeed and it needs much less current from the battery than a standard flashlight bulb... Of course, the light produced does not have the ideal spectral energy distribution needed for reading, etc., but it does work very well as an emergency long-lasting lamp, which is practically break-proof!
By the way, the eight red light-emitting diodes came from the annunciator panel of a dead telephone modem, struck by lightning during last summer's thunderstorm season... and although the modem was severely damaged, the red LED's survived. So following my standard practice of recycling electronic components from all sources, I de-soldered them from the modem's board and made the NEW EMERGENCY LED HOMEBREW FLASHLIGHT.... All I needed to do was to solder all the eight diodes in a parallel circuit, and calculate the series current limiting resistor that is essential for the LEDs to operate safely.
Don't forget that light-emitting diodes operate at voltages that are specifically related to their color, and that they need a specific current flowing through the semi-conductor junction in order to operate properly... And before I forget... BE EXTREMELY CAREFUL with polarity, as light-emitting diodes are damged beyond any possible repair if the circuit's polarity is reversed by accident... Be really sure of the LEDs polarity before soldering them into any electronic device!
Now, thanks to this wonderful idea I have no more flashlight bulb filaments to worry about! LED lamps with appropriate spectral energy light distribution should be excellent replacements for the very noisy energy-saver fluorescent lamps that are now becoming one of the radio listener's worst nightmares!
You are listening to Radio Havana Cuba, and this is a special edition of Dxers Unlimited devoted to RADIO NOISE SUPPRESION...
LED lamps now becoming available are one nice way to go in the future, as soon as they become cheaper, or you can assemble your own homebrew LED lamps, just like I did... but right now you can reduce your radio noise by changing your fluorescent lamps periodically, as soon as they show blackening at the tube ends. When standard fluorescent lamps show black stripes at their ends, it is time to replace them, because that's when they generate a lot of radio frequency noise. Another RADIO NOISE SUPPRESION TIP: install AC power line filters on the lines that supply the room where you have your radios... the filters must be installed at the electricity input box, and one right next to the radios. You will also need a good low-resistance ground connection for the AC power line noise filter.
When properly built and installed, the AC power line noise filters will reduce the RF noise reaching your radio via the AC supply significantly, and one added bonusm in case you are an active radio amateur, is that the filter will block any RF generated by your transmitter or transceiver from entering the household wiring and producing interference with your TV set, VCR or stereo!
Another good idea for reducing radio noise is to run a complete check of your home's electrical system, done by a professional electrician of course... It is amazing to see how many home electrical systems have gone without any kind of maintenance whatsoever for years and years, and how preventive maintenance can help not only reduce radio noise, but also even prevent dangerous problems from happening. Not too long ago, while trying to find the source of terrible radio noise at a friend's home, we found a very loose terminal at a circuit breaker that was arcing almost constantly.... a likely candidate to generate an electrical fire in the not-too-distant future, if we had not caught it in time!
Amigos, my friends, mes amis... fighting against radio noise sources is not an easy job... But you will certainly learn a lot about radio by attempting to reduce your present noise levels... YES, that tick tick tick that was spoiling your AM DX session was from an aquarium pump, while the constant BUZZ came from a light dimmer that may be replaced by a very conventional on-off switch, and the soft buzz that you have heard all across the 60 meter Tropical Band could be completely wiped out by just replacing four or five of the fluorescent lamps that are the most used ones in your home environment.... Another tick, tick, tick type QRM was from one of the electric fences now so popular in the countryside, or maybe your source of radio QRM-causing noise was an arcing lightning arrester located not far from your home, at the power company's distribution transformer!!!
If you have any questions related to radio noise interfering with your reception, feel free to send me an e-mail with the full explanation of your problem, and I'll try to help you first to find the source, and then attempt to reduce or eliminate it completely. Send your radio noise problem description to arnie@radiohc.org or VIA AIR MAIL to Arnie Coro, Radio Havana Cuba, Havana, Cuba.
Arnie Coro CO2KK
Havana, Cuba
August 18, 2001Postal address:
Arnie Coro, "Dxers Unlimited"
Radio Havana Cuba, Havana, CUBA
e-mail: arnie@radiohc.org
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