Radio Habana Cuba: Dxers Unlimited Special Edition for 25-26 September, 1999
By Arnie Coro, radio amateur CO2KK
Hi amigos! Welcome to this special edition of Dxers Unlimited, your favorite radio hobby show on short wave. I am Arnie Coro, radio amateur CO2KK, your friend here in Havana, and host of this twice weekly program, devoted entirely, absolutely to the wonderful hobby YOU and I enjoy so much: RADIO.
And here is item one: How many Dxers Unlimited's listeners can't install an external antenna for their radios? Listen to this question again... how many of YOU can not install a nice external antenna? Well according to my statistics, no less than one-third of Dxers Unlimited's regular listeners are forced to use one kind or another of INDOOR or at the best BALCONY or WINDOW mounted antenna systems... That's why compact, efficient indoor and easy to install and remove BALCONY and WINDOW antennas are so important... YES, you guessed right, that't the main topic in today's edition of Dxers Unlimited, so be ready to tape, or take notes, if you are one of the many having to deal with antenna restrictions from landlords, condomium rules and city regulations... I can assure you that there are many options available, and that YOU, all by yourself can install antenna systems that will outperform the radio's telescopic whip many times... Propagation conditions on the higher bands are improving as the solar cycle continues to move UP...You see amigos, it does pay to keep monitoring 10 meters, especially when solar activity is moderate or high! Now please stay tuned for more radio hobby related items, coming up in a few seconds... A Dxers Unlimited's SPECIAL REPORT... INDOOR, BALCONY and WINDOW antennas...
You are listening to Dxers Unlimited, the station is Radio Havana Cuba, and our URL for the website is www.radiohc.org and be on the lookout for an update of Dxers Unlimited's webpage coming up soon... again, the URL, just in case there was a little fading on the signal, is www.radiohc.org, and you can keep in touch directly via e-mail, just send me your signal reports, comments and new ideas or questions for Dxers Unlimited to arnie@radiohc.org.
And now, as promised... A Dxers Unlimited 's SPECIAL REPORT... YES AMIGOS, no less than a third of the worldwide shorwave audience happens to face difficulties to install an EXTERNAL antenna system. Many listeners have to keep up with just their radio's telescopic whips, which are, VERY INEFFICIENT antennas to say the least. Let's face it... even when fully extended, the best of the typical whip antenna is no more than about one and a half meters long... standard whips that I have measured here are smaller... usually about one meter or for those of you not familiar with metric, around three feet long when extended. Not much of an antenna, if you want to pick up signals on frequencies in the 5 to 15 megaHertz range... Want to know why? Well here is the simple arithmetic... a 5 megaHertz Tropical Band Station, like Cuba's Radio Rebelde on 5025 kHz, operates on a wavelength very near to 60 meters.... so your radio's whip antenna, when fully extended is just one sixtieth of a wavelength long..., Yes you heard it right, your one meter or approximately 3 feet long telescopic whip antenna is just one sixtieth of a wavelength... let's figure out that in percent. Calculator ready? Here we go, if 60 meters is 5 megaHertz wavelength, OK? Sure, now 1 meter is what percentage of 60 meters? Easy...no problem, here is the answer, 1.66 percent... So your telescopic whip is just 1.66 percent of a wavelength long at 60 meters, and the situation does not improve much at even higher frequencies, for example, let's say you want to pick up Radio Havana Cuba's ever popular 9820 kiloHertz frequency... First let's calculate 9820 kiloHertz 's wavelength... easy too... Wavelength in meters, equals the constant 300, divided by the frequency in megaHerz... which is 300 divided by 9.820, and that equals... let's see 30.54 meters wavelength... NOW, here the situation is a bit better, but see, not much... Let's calculate how long, percentage wise, is the one meter or 3 feet radio's telescopic whip here on 9820 kiloHertz, which is, 30.54 meters... OK, here we go again with the calculator... ANSWER, just 3.27 percent, again, here is the result, the radio's telescopic whip, when receiving RHC on 9820 kiloHertz is just 3.27 percent of a wavelength long... See my point? In other words, your antenna is VERY, VERY short in terms of wavelength, so its overall efficiency is VERY, VERY low...
Even on the 19 meter or 15 megaHertz band, the typical one meter long whip is one twentieth of a wavelength at the operating frequency, still a POOR antenna by all standards... That's why, when Dxers Unlimited's listeners ask me how they can improve their reception, the first thing I tell you is to ADD SOME WIRE connected to the radio's telescopic whip, even if your receiver does not have a connector for an external antenna. Even three or four meters of insulated wire placed near a WINDOW, or along the BALCONY rail will improve the reception quite a bit. In fact, if you are able to add about 5 meters of wire to the whip, things beguin to look good on the three higher international short wave broadcast bands, that is 13 meters or 21 megaHertz, 16 meters or 17.5 megaHertz and 19 meters or 15.1 megaHertz... And if broadcasters decide to use the 11 meter band during the peak of the solar cycle, that 5 meter long wire will also help a lot to pick up stations on that little used band that spans from 25 to 26 megaHertz.
So amigos, if you are facing the NO EXTERNAL antenna restrictions, buy yourself a spool of plastic PVC insulated speaker wire, and start analyzing how it can be installed as close to a WINDOW, or BALCONY as possible. Wooden houses have the advantage that wood is transparent to radio frequency signals, so you can install a nice and efficient ATTIC antenna, if's your home's main construction material is WOOD. But this ADD-ON WIRE is just the beginning, you can build several antennas that when installed indoors will perform very nicely. Stay tuned, I'll be back in a few seconds with more indoor antenna related info, direct and from the source: Dxers Unlimited!
And remember YOU HAVE QUESTIONS? Arnie has the answers here for you via email to arnie@radiohc.org. Our postal mailing address is very easy to remember too... send your signal reports, comments about the show, and questions about radio directly to me; Arnie Coro, Radio Havana Cuba, Havana Cuba, that's an easy one to remember isn't it, and I will certainly QSL back to you.
Now part two of this Dxers Unlimited SPECIAL REPORT -- INDOOR BALCONY AND WINDOW antennas for short waves...YES, the easiest one to install is the ADD ON wire to the telescopic whip. I recommend ALWAYS to use insulated wire for safety, and to keep the antenna wire as far away from appliances as possible... that means your ADD ON wire should be routed away from TV sets, computers and the like... One popular installation procedure calls for an UNDER THE CARPET antenna, in which the wire is located as close as possible to the walls of the house... Another often-used approach is to run the wire under the BALCONY RAIL. My advice is for you to run many tests, until you find the best possible location, were the antenna will pick up more SIGNALS and LESS NOISE. NOW, I warn you this may take some experimentation, until you find the right spot.
Now for the NUMBER TWO indoor antenna system, this is a bit more complicated, but it works very well, due to the fact that it is a TUNED ANTENNA SYSTEM... This second option is nothing more than the so called MAGNETIC LOOP antenna, which has among its significant advantages the fact that it picks up the MAGNETIC VECTOR of the radio wave, making it an ideal LOW NOISE system for indoor use. OK, YES, I agree, it sounds a bit too techie... a bit too technical, but after all, radio is a technical hobby amigos. Well, back to the MAGNETIC LOOP... I will not be able to describe this antenna here today, all I can tell you is to try to look for more information about MAGNETIC LOOP ANTENNAS in technical publications, like amateur radio antenna handbooks and technical magazines. MAGNETIC LOOPS do require constant retuning when you change frequencies, but they are compact, fairly efficient, and above all, for indoor installations, or balcony antennnas, they will be able to provide you with an excellent signal to noise ratio, as a matter of fact, the MAGNETIC LOOP can be moved so as to minimize local interference, like computer generated garbage, TV synchronization pulses and the like. Although there are several commercial versions of the MAGNETIC LOOP antenna system, they ALL seem to be extremely expensive, nd to be honest, I have never found out why no one is manufacturing a LOW COST, but well-built, Magnetic Loop Antenna for receiving and low power transmitting. Maybe that's the problem: manufacturers are targeting radio amateurs who need magnetic loops that can handle at least the typical 100-watt ham transsceiver... So, the non-existence of a low cost commercial magnetif loop has given me a very good reason to recommend that BUILDING YOUR OWN is the right way to go.
Once you have the technical information at hand, you will see that a receive-only magnetic loop antenna for the frequency range from 6 to 18 megaHertz, that is a three-to-one frequency ratio, is not that difficult to build. Commercial antennas presently available use motorized remote tuning and are usually designed for the 10 to 30 megaHertz frequency range, which makes reception impossible on the four most popular international short wave broadcast bands, that is the 6, 7 and 9.5 and 11.7 megaHertz, or 49, 41, 31 and 25meters as they are popularly known... YES AMIGOS, there are INDOOR, BALCONY and WINDOW antennas that work a LOT BETTER than your receiver's fully extended telescopic whip... and those antennas can be built and installed at low cost too.. So go ahead and try at least the 5 meter long wire connected to your telescopic whip and hear the difference! Then drop me an e-mail and tell me how your new antenna compares with receiving just with the telescopic whip!
Well amigos, this is all for today's Dxers Unlimited's special report. Now, as always, at the end of the show, here is Arnie Coro's exclusive, but not copyrighted HF propagation update and forecast. The present HF propagation conditions can best be described with a single word... DISAPPOINTING for most of the users of short wave, except those amateur radio operators devoted to the VHF 6 meter or 50 mHz band. For 6 meter enthusiasts, the MAGIC BAND has brought this past week phenomenal DX conditions, including such very rare paths as Australia to North America in the late afternoon and early evening local time here in the Americas... For short wave listeners, the geomagnetic storm caused by the impact upon the Earth's magnetosphere wiped out even some of the regular stations.
Now, here is the forecast... the word describing it is again... DISAPPOINTING, as solar flux is more than 80 points BELOW what scientists expected for these days sorrounding the equinox. Anyway, keep those radios on, as equinoctial DX should begin to improve, especially on the lower frequencies, due to the much lower solar activity. So, it's time for AM medium wave and Tropical Bands Dxing amigos!!! AND...Don't forget to send your QSL requests, signal reports and comments about the show to arnie@radiohc.org, and via AIR MAIL to Arnie Coro, Dxers Unlimited, Radio Havana Cuba, Havana Cuba...
Arnie Coro CO2KK
Havana, Cuba
25 September, 1999Postal address:
Arnie Coro, "Dxers Unlimited"
Radio Havana Cuba
PO Box 6240, Havana, CUBA 10600
phone: 53-7-814243
phone res: 53-7-301794
e-mail: arnie@radiohc.org
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