RADIO HABANA CUBA
DXERS UNLIMITED
WEEKEND EDITION
SATURDAY, APRIL 28, 2001
By Arnie Coro CO2KKSend your comments, questions and ideas to: arnie@radiohc.org
Hi amigos, welcome to the weekend edition of your favorite radio hobby program on short wave and on the web at our Dxers Unlimited website! I am Arnie Coro, radio amateur CO2KK, your friend here in Havana, and it's nice to share with you the next almost 18 minutes of air time....
As always, first things first, and today's first item deals with the unexpected early arrival of a stream of charged particles from the Sun... apparently, scientists could not figure out the actual speed of the solar wind enhancement, and they thought that the Earth would intercept the stream of particles from the coronal mass ejection caused by an M7 solar flare sometime Sunday... BUT, the speed was much higher, and I found the HF propagation conditions changing quite a bit Saturday morning my local time here in Havana due to the interaction between the high speed stream of charged particles and the ionosphere...
Item two: Meteor Scatter propagation is one of those very unusual ways that provide unique amateur radio contacts and FM and TV DX loggings... Today, item two will be entirely devoted to Meteor Scatter Propagation, because we will soon be seeing one of those yearly Meteor Showers that provide both radio amateurs and radio and TV Dxers with a lot of fun....
Item three: subscribe dxers - underscore - l like in lima.... yes, you can subscribe to the Dxers Unlimited's scripts and information distribution list... have paper and a pen or pencil ready to copy the easy-to-follow instructions on how to subscribe to this very useful and fully automated service that sends to your e-mail address each Dxers Unlimited script as soon as I place it at our station's e-mail server.... AND NOW, thanks to Danny, our Webmaster, we can add photos and circuit diagrams to the scripts too... So when I talk about a new circuit, for example, if you are subscribed to Dxers Unlimited's distribution list, you will be able to see the circuit diagrams too....
Item four: Well, that's a surprise, while item five is the not copyrighted, in the public domain, Arnie Coro's exclusive short wave plus 6 meters propagation update and forecast. Stay tuned right on this same Radio Havana Cuba frequency for more radio hobby related information. Margarita Delgado is my sound engineer and producer, we are both here at RHC studio number 7 and will be back with you in a few seconds...
And now, here is item two.... LET's TALK ABOUT METEOR SCATTER PROPAGATION, a mode that can add a lot of fun and many new stations to your log. SO let's talk about METEOR SCATTER, a very unsual mode of propagation that is one of the most fascinating challenges a radio hobbyist can find! There are no less than 17 main yearly METEOR SHOWERS, yes no less than 17 yearly regular events, and as I said at the begining of this show, one of them is about to take place.
It is not the most spectacular, but the ETA AQUARIDS seems to be somehow linked to the appearance of SPORADIC E propagation every year from May first to May seventh, peaking around the fourth of May. For non-astronomers, the news that many MILLIONS -- yes, MILLIONS -- of meteors enter the earth's atmosphere every day may sound amazing, but that is the fact... the meteors range in size from a grain of sand to much bigger rocks, but the fact is that even a meteor the size of a grain of sand can produce a trail that can be visible to the naked eye for a short time.
Meteors the size of a small stone, like a pebble, can be seen leaving a trail that lasts several seconds... Those trails form when the meteor enters the upper atmosphere and burns up. Their usual entry speed is anywhere from 10 to 75 kilometers per second, and they burn at altitudes of from 80 to 120 kilometers above the Earth... NOW, that's the basic information. From now on, we can start, like Sherlock Holmes, making deductions...
Altitude from 80 to 120 kilometers -- well, that's the lower ionosphere, between the D and E layers... and speeds of up to 75 kilometers per second will vaporize the meteors, leaving, you guessed right, an ionized trail... Well, then, an ionized trail at say 100 kilometers altitude for a few seconds, will be capable of bouncing VHF Signals back to Earth, and that's exactly what happens. This is what TV DX and FM broadcast band enthusiasts look for during the meteor showers... They keep their TV sets and FM radios on, tuned to a local empty channel, and leave a specially prepared VCR recording the event, having to change the tapes once every 6 hours. If they are lucky enough, several meteors will impact the upper atmosphere during the observation period, and that may lead, hopefully, to a full station identification. By the way, ionized trails left by meteors are very long and thin; some can be up to 40 kilometers long, but only five to ten meters wide. See how much interesting radio hobby-related information you learn about here at Dxers Unlimited, amigo!!!
Radio amateurs also use meteor scatter propagation to work stations in the VHF frequency range that are out of the normal ground wave coverage, and they do it with great success, because today's high tech equipment makes it much easier...
The 28, 50 and 144 megaHertz amateur bands, that is 10, 6 and 2 meters, are the most popular ones for meteor scatter contacts, but evidence of meteor scatter propagation can be heard on frequencies as low as 10 megaHertz during solar minimum years, while the upper limit seems to be, at least for radio amateurs, the 70 centimeters or 420 to 450 megaHertz band. The next Meteor Shower will be in June; it is known by astronomers as the June Lyrids, and spans from the tenth of June to the twenty-first of June and again, it seems to be connected or related in one way or another with the June Sporadic E peak in the northern hemisphere.
According to a very accurate description that I once heard at a VHF amateurs' conference some five years ago, meteors entering the Earth's upper atmosphere provide a short-lived super ionosphere that, on some special occasions has provided amateur radio contacts on frequencies as high as the 70 centimeters or 420 to 450 megaHertz amateur band, as I was just telling you a while ago... But, the usual two-way contact using meteor scatter is done on the 10, 6 and 2 meter bands, with the two meter contacts enjoying the highest popularity, although meteor scatter on six meters is somewhat easier to achieve...
Well amigos, I hope you enjoyed this basic primer on meteor scatter propagation and, as always, if you have any questions, just send it to me via e-mail at arnie@radiohc.org and via Air Mail to Arnie Coro, Radio Havana Cuba, Havana, Cuba.
You are listening to Radio Havana Cuba, the name of the show is Dxers Unlimited, I am Arnie Coro, your host here at this twice-weekly radio hobby program, and here is the information on how to subscribe to Dxers Unlimited's scripts distribution list via e-mail.... send an e-mail message to majordomo@rhc.cu, leave the subject line empty, and in the body of the message write the following: subscribe dxers_l. You will then receive a confirmation message from the majordomo automated list server distribution system, and from that moment on, each and every script of Dxers Unlimited will be reaching you via e-mail... Hope you enjoy this new service, and any comments about it, just send them to me.
NOW, SURPRISE: Item four.... YES.... GOOD NEWS: The first prototype of a solid state REGENERODYNE receiver is sitting right next to where I am writing the script of today's Dxers Unlimited, Saturday morning here in Havana, its just past eleven o'clock in the morning here, and I am listening to a station on the 25 meter band with the solid state REGENERODYNE. For those of you like my good friend Tim Rasch who have followed the story, this solid state receiver is a unique design, combining what could be described as the best of not two but three worlds... as it is solid state, uses a very sensitive and easy-to-adjust regenerative detector and should be rather easy to homebrew. It has a low parts count and there is a lot of room for experimenting with this nice little radio. I even designed three different front ends to be able to test drive them with the basic tail end of the radio, which is using a dual-gate MOSFET regenerative detector working into a high gain, low noise audio amplifier... So far all three front ends have worked quite well... So I will probably place the diagrams with an upcoming script of Dxers Unlimited, so that you can choose the one you like.
Let me tell you that the prototype receiver picks up AM, CW and SSB signals. As a matter of fact it does quite well on SSB, something I could verify this morning by tuning in to a popular LDOC, or long distance air route operating center frequency, in the 11 megaHertz range. Aircraft SSB voice communications came in loud and clear as they went past oceanic route waypoints. Also I may add that the receiver's frequency stability is excellent, too. So that was today's surprise, Arnie Coro's SOLID STATE REGENERODYNE prototype one is now under test, and so far it seems to be an excellent receiver.
And now amigos, as always at the end of the show, here is Dxers Unlimited's HF propagation update and forecast... AURORA ALERT for Dxers Unlimited's Canadian listeners, amigos... you may perhaps be able to see another nice AURORA BOREALIS display late Saturday night - early morning Sunday local time... A propagation disturbance should be in progress as you listen to this program, but I don't think it is going to be a major geomagnetic storm at all. Anyway, be on the alert to pick up those rare DX stations that pop up out of nowhere, like those pop up ads on the WEB, when a propagation disturbance is in progress...
Six meters operators, keep your antenna looking SOUTH for possible F2 propagation, while sporadic E events may happen at any time now as we enter into the Sporadic E summer season, which should be in full swing this next week... Solar flux is 190 and apparently moving down now... but not really sure about this; THE MORE-trusted effective sunspot number is at a nice 148, and that's the data to punch into your HF propagation forecasting software...
See you at the mid-week edition of Dxers Unlimited, next Tuesday and Wednesday UTC days... Don't forget to send me a signal report and comments about the show to arnie@radiohc.org, and if you are already an amateur radio operator, look for me at CO2KK on 28.5 megaHertz when the 10 meter band is open!!!
Arnie Coro CO2KK
Havana, Cuba
April 28, 2001Postal address:
Arnie Coro, "Dxers Unlimited"
Radio Havana Cuba, Havana, CUBA
e-mail: arnie@radiohc.org
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