Radio Habana Cuba: Dxers Unlimited mid-week edition for December 5 2000
By Arnie Coro, radio amateur CO2KK
Hi, amigos!!! I am sure that most of you have enjoyed the excellent short wave propagation conditions that have brought a lot of Dx during the past 5 days!!! NOW, the Sun is taking a little rest; there are only 4 clearly visible active sunspot regions, and none of them is particularly complex... so solar activity is expected to go from low to very low, and the daily solar flux will very probably bottom around 140 units in a short time. Then, another sub-cycle will start and we may see some nice fireworks again, big solar flares and their associated coronal mass ejections as solar cycle 23 continues to puzzle forecasters once again!!!
For those of you who will participate in the 10 meter band contest this coming weekend... my special contest forecast will be on the air later today, right here at the mid-week edition of Dxers Unlimited.
Now item two: feedback from YOU, the avid and faithful Dxers Unlimited's listener, is what makes this program different from other radio hobby shows... Feedback coming in via e-mail gives me a very good picture of what are the main interests of listeners ... these range from a 7-year old girl who monitors the show with a regenerative receiver that her dad gave her as a present, to an 88-year-old radio amateur who has enjoyed the hobby since he was in his teens... and in between those 81 years of difference, there are young radio amateur operators, experienced contest operators who monitor the propagation forecasts and even ask for special ones just before a major contest, and then I get Air Mail postcards and e-mail letters from first-time listeners who just came across the show quite by accident while tuning around the shortwave bands. There are even several very interesting reports that have to do with our 6000 kiloHertz transmitter, which in some radios can be picked up right at the very end of the AM broadcast band due to the technical characteristics of superheterodyne receivers' local oscillators!
Item three: Read at one of the e-mail reflectors related to amateur radio that I subscribe to... A ham asking for advice: he is buying a new house, and the real estate people are offering him a nice home that has high voltage transmission lines some 150 meters away from the backyard... NOW, I am sure you all guessed right: If you are a radio enthusiast, any location near high voltage transmission lines is a place to avoid by all means, especially if the lines are transporting electricity at voltages higher than 10 kilovolts, or ten thousand volts, but even lower voltage power distribution lines, like 2.4 kilovolts or 4.4 kilovolts, can generate a lot of noise that will make your radio reception difficult, to say the least!!! So, follow your friend Arnie Coro's advice, and if moving to a new location, carefully check for the presence of high voltage transmission lines near your possible new location... and go as far away from them as possible!
Your radio is tuned to Radio Havana Cuba, the name of this show is Dxers Unlimited, and it will continue in just a few seconds. Margarita Delgado is my sound engineeer and producer, I am Arnie Coro, and if you notice a little distortion in my voice, do not blame our transmitters or your receiver. It's me; I caught a bad cold day before yesterday when the weather changed abruptly here... Stand by now on this same frequency...
Amigos, as I said earlier, it is so nice to do a show that receives immediate feedback from listeners around the world... Now that the solar cycle is near its peak, I receive reports from parts of the world that are not within our antenna's primary target areas.. For example, our 13750 kiloHertz English broadcast to Europe is making it quite well into Australia and New Zealand when the solar flux is running above 150 units and there are no geomagnetic disturbances... Same happens to 6000 kiloHertz that is heard very late in the evening in Europe quite regularly, although it is beamed to the East Coast of North America... And it is nice to receive such nice comments from first-time listeners who pick up the show quite by chance.
Now, item four: The information provided recently about wall plug power sources for radio receivers, the so-called wal warts, made many Dxers Unlimited's fans reach for their computers and send me an e-mail about the topic; also I expect that in about three or four weeks, a lot of the regular mail will deal with this topic too. Well, here are some very good ideas that came in: The use of a gel cell 6 volt accumulator, the ones used by alarm systems, was suggested by a listener from California; he is actually using a brand new, 6 volt gelled electrolyte accumulator that he bought brand new... then I told him that those accumulators are often found for free at workshops that do regular smoke, fire and intruder's alarm installations and maintenance. The fact is that insurance companies demand that those 6 volt accumulators, normally used in pairs, be replaced periodically, no matter how good they may be...those outfits find themselves with many 6 volt gelled electrolyte accumulators that they have to send to a recycling facility at a certain cost. SO, many of them happily give away for free those accumulators to ham radio operators and short wave listeners. Hotels, hospitals, and public buildings are also a source of used but in good working order gelled electrolyte accumulators. Then ham radio ingenuity will come in... and you will make your own trickle charger, that will keep those batteries operational for a long loooong time indeed!!!
YET another source of those nice, typically 7 ampere hour, accumulators are computer UPS supplies, but my experience shows that those coming from a broken down UPS, or uninterruptible power supply, are usually not in such a good state as the ones used in alarm systems, as the UPS batteries do have a heavy workload, in contrast to the standby service provided by the accumulators on the alarm systems. Nevertheless, whichever source you find for the typical 7 ampere hour accumulators, by all means take them home, make a trickle charger following my instructions -- soon to be explained here during the weekend edition of Dxers Unlimited -- and enjoy CLEAN POWER: pure Direct Current without any trace of power line spikes, noise, etc. Connecting two of them in series makes an excellent 12 volts DC supply to power your amateur radio handheld 2 meter or 70 centimeter band FM transceiver for a LOOONG time. Just make a power cable from the series connected accumulators to your handie talkie, and do remember to include a fuse that is appropriately rated, just in case something goes wrong...
SI AMIGOS, OUI MES AMIS, YES MY FRIENDS... you can make yourself a nice source of clean DC, either 6 or 12 volts, by putting to good use the gel cell accumulators that are replaced as routine maintenance in many applications!!! AND, it you need a lower voltage for your radio, say 4.5 volts, it is very easy to wire up a voltage regulator integrated circuit and adjust the output as required. For voltages in between 6 and 12 volts, the same circuit will serve you well. I use here an LM317 regulator, which allows me to go from 1.25 volts all the way up to 12 volts by just turning a variable resistor.
If you want to know more about gel cell accumulators and how to use them for your radios, e-mail me at arnie@radiohc.org, or send an AIR MAIL postcard to Arnie Coro, Radio Havana Cuba, Havana, Cuba, and I will gladly answer your questions.
You are listening to the mid-week edition of Dxers Unlimited; the smoothed sunspot number today is 107, and that is a moving average taken from a 13-month series... today's actual sunspot count, Tuesday UTC day was 120, contrasting with yesterday's sunspot count that was 186!!! This is just to show you the wide range of day-to-day variation in solar activity.
Now here is item five: the very popular visit to Arnie's workbench! Well, guess what's going on here... almost finished now is a nice two vacuum tube regenerative receiver that uses a rather unusual circuit, a dual triode configured as a cascode regenerative detector... I tested it using my workbench audio amplifier and power supply, as what I wanted to experiment really was with the regenerative detector itself, I just wired it up, and used both the general purpose power supply and audio amplifier. NOW, for those of you who enjoy experimenting with radio and electronics, this is a good idea: Build yourself two variable power supplies, one for the 0 to 30 volts DC range at a current rating of anywhere from 2 to 5 amperes, and another power supply, for vintage radios and experiments with vacuum tubes, that will provide various filament voltages and a high voltage of between 100 and 400 volts DC at a current rating of no less than 100 milliamps. Then, add to this a sensitive audio amplifier and you are ready to both fix equipment and test new circuits without having to worry about from where to power them up!!!
Tomorrow I will wire up the cascode detector's own audio amplifier and power supply, now that I know that it works very well... With a 3-meter-long indoor wire, about 10 feet, hanging inside my shack, I could pick up several European SSB amateur stations on the 7 megaHertz or 40 meter band Monday evening my local time, when the sun was just going above the horizon in Europe and it was midnight here in Havana!!!
And now amigos, as always at the end of the show, in the public domain, for your enjoyment, here is Arnie Coro's Dxers Unlimited's HF plus 6 meters propagation update and forecast:
Solar activity is now moving DOWN, but there is enough solar flux to keep the higher bands ticking during your local daylight hours. The 10, 12 and 15 meter bands will be open to one part of the world or another during many hours every day, but 10 is going to close earlier now that the solar flux went below the magic 150 solar flux units mark.
For the upcoming weekend 10 meter band contest, I advise participants to wake up very early during the second day of the contest, as there are very good chances of working long path propagation for a brief period in North America and the Caribbean just around sunrise here local time. Also, be on the lookout, as soon as the contest starts, for possible DX conditions to South America and Asia Pacific if you are located in North America or the Caribbean. I don't expect solar flares during the next several days, but the SUN is the SUN, and during the peak period of a solar cycle anything can change in a few hours with a new solar active region growing out of nowhere and producing flares and coronal mass ejections.
Look for me on 10 meters, I continue to have a nice time talking to Dxers Unlimited's listeners on 10, around 28.500, and when not there, I am usually monitoring 28.885, the international six meter band operators' coordination frequency, so if you hear me there, give me a call and we move away from that channel and have a nice QSO a few kiloHertz up or down!!!
See you at the weekend edition of the show, and don't forget to set aside a little time when at the computer and tell me how much (or how little) you liked this show, send me your questions, ideas and comments to arnie@radiohc.org. I really appreciate it very much, and all e-mail is answered on the same day for sure... See, I do it myself from my computer!!!! If not yet in Cyberspace, send your AIRMAIL postcard or letter to Arnie Coro, Radio Havana Cuba, Havana, Cuba...it will take longer to receive my reply, but be sure that we do answer all our correspondence and QSL one hundred percent.
Arnie Coro CO2KK
Havana, Cuba
December 5 2000Postal address:
Arnie Coro, "Dxers Unlimited"
Radio Havana Cuba, Havana, CUBA
e-mail: arnie@radiohc.org
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