Dxers Unlimited weekend editions
by Prof. Arnaldo Coro Antich
radio amateur CO2KK
Radio Habana Cuba
Radio Habana Cuba
Hi amigos radioaficionados around the world … Welcome to the weekend edition of your favorite radio hobby program, the one and only that provides really up to date high frequency decametric bands propagation updates and forecasts, especially prepared for broadcasting on this program.
We also reply to your radio hobby related questions directly via e-mail or AIR MAIL, and provide circuit diagrams and technical information about simple radio receivers that can be built on top of your kitchen table or computer desk.
By the way one of the most recent short wave solid state receiver circuits uses a rather unusual regenerative detector running two PNP silicon small signal transistors.
What is amazing about this particular circuit is that it provides a very smooth regeneration control by means of a ten thousand ohms carbon potentiometer.
I tested this radio with just a one meter long wire connected to the antenna terminal, and it picked up several Cuban , Mexican, Dominican Republic and USA amateur radio stations with excellent stability and good quality audio.
The original circuit is not mine , it was posted at several amateur radio and short wave listeners website, but I believe that many of those who saw the circuit and how simple it was, just thought that it will not be able to back the claims of the designers.
The basic building block of this radio is the two PNP transistors detector followed by one stage of audio ,the radio is then connected to an external audio amplifier module that can be as simple as a computer loudspeakers set.
I keep a much modified computer loudspeakers set at an easy to access position on my main workshop electronic assembly table, and it has many uses, including helping to fix broken equipment by means of a very simple signal tracing attachment that is connected to the computer amplified loudspeakers .
Item two: Personal attacks, insults , lack of respect , and poor spelling are among the quote REGULAR FEATURES , unquote, of the postings contributed to several short wave listening and radio hobby Internet lists and websites by a self proclaimed expert from Oklahoma , United States of America...
Among the latest examples of such attacks this person has posted is one that shows once again his total ignorance about a subject that he proclaims to be one of the world's top experts...
Frequency Management !!! The worldwide decametric broadcasting frequency management system developed by the ITU, the International Telecommunications Union, the oldest of the United Nations specialized agencies, began way back in 1948, at the Mexico City conference that among other practical results divided the world in the so called CIRAF zones, that clearly define the areas to where the stations broadcast according to their interests in reaching specific audiences.
Twice every year now, and years ago four times a year, the ITU receives and processes the frequencies that the stations intend to use, in order to optimize as much as possible the use of the limited natural resource we all know as the radio frequency spectrum.
The process starts with filling in a very detailed entry form, that includes the engineering data required that is then fed to an ITU specially developed software program .
Each station sends this data to the ITU either directly or by means of some forms of sub regional, regional or voluntary associations , but it is very clear that the ITU data for each of the two yearly periods is what provides the station's engineering staff with the best possible information of the coverage that a broadcast is achieving.
It is absolutely impossible, with the number of stations on the air, even now that several international broadcasters have decided to stop their short wave transmissions, to achieve a worldwide clear channel on any of the lower frequency international shortwave broadcast bands...
It is then necesssary to go through a process of preparing the schedule for a given period, sending it to the ITU, waiting for the ITU to run the complex software , and then receive the data about the expected quality of each transmission.
And all this process starts with each national telecommunications administration of each ITU member nation registering with the ITU the international short wave broadcast transmissions that they plan to put on the air for the next upcoming period.
If the stations are not registered with the ITU, they simply do not appear in the data base !!!
And this is something that happens more often than anyone may think, and it does cause problems .
Add to the lack of registration , the pretention by some broadcasters to cover a much larger target area than what the equipment they are running can really provide... and also include into the problem , the lack of knowledge among those doing the frequency management of some stations , about the specifics of antenna patterns, antenna gain, front to back ratio , plus adjacent channel incompatibility etc.
For your information amigos, all the attacks against Radio Havana Cuba and to me , coming regularly from the so called World of Radio self proclaimed expert , increased since our station began to use on the 8th of November a new frequency beamed to Central North America, using a highly directional curtain array , type HR 4, 4, 0,8 , an antenna type certified by the International Telecommunications Union as a highly directional and high front to back ratio antenna system.
The frequency selected for the B10 ITU period for that service is
6050 kiloHertz, that appears as totally blank and clear for the CIRAF
Zones to which we are broadcasting, in other words, no other station has
registered with the ITU that frequency with the intention of
broadcasting to Central North America, something that we have checked
regularly during the schedule times when 6050 kiloHertz is used.
In other words, the use of that frequency is in full compliance with the ITU frequency management recommendations... and the daily excellent reception reports we are receiving from both the areas of the USA and Canada, to where the 6050 kiloHertz Radio Havana Cuba transmissions are beamed , confirm that this is a good channel, clear of any incompatibility and causing, no incompatibility to any other registered user , as shown by the ITU B10 date base..
Stay tuned for more radio hobby related information, coming on this weekend edition of Dxers Unlimited that is now on the air after the top of the hour newscast on Sundays and Mondays UTC days.
I am your host Arnie Coro , radio amateur CO2KK, back with you in a few seconds...
This is Radio Havana Cuba, the name of the program is Dxers
Unlimited, and yes amigos, there are now some 86 different ways of
enjoying the radio hobby.... with one of the latest ones added having to
do with the use of light beam communications during amateur radio
The availability of laser pointers that can be easily modulated has added a new twist to the ham radio VHF, UHF and Microwaves contests... because it is now possible to hold two way contacts from mountain top locations with stations located tens of miles away, by just running a laser pointer and a sensitive light beam receiver coupled to a telescope of a Fresnel lens system.
The use of high power Light Emitting Diodes is also making headway in the field of amateur radio light communications....
And talking about ham radio, let me tell you that the Super Islander version 5.2 simple short wave receiver for the amateur bands between 160 and 30 meters is now almost finished , just waiting for a good friend to complete the nice box where the receiver is going to be fitted permanently.
The Super Islander version 5.2, includes a more sophisticated pair of active audio filters, that do improve reception on both CW and SSB, and it has also benefited from the use of more elaborate VFO or variable frequency oscillator circuit.
As a matter of fact, this radio qualifies among the low parts count
receivers, and I must add that the layout of the printed circuit board
has taken into consideration the fact that beginners have a hard time
handling the soldering iron, and that is why the printed circuit board
traces are well separated from each other fo facilitate the assembly
without the fear of developing short circuits with soldering blobs !
Home brewing simple radio receivers is one of the 86 ways that you and I enjoy this wonderful hobby, yours and mine … RADIO !!!
And now amigos here is Arnie Coro's Dxers Unlimited's HF propagation update and forecast with the addition today of a special winter Sporadic E season forecast...
Yes amigos, the winter sporadic E season of the Northern Hemisphere is due to start at anytime now, and my analysis of prevailing solar conditions calls for a rather active winter Sporadic E DX season indeed !!!
HF conditions are now dwindling because an all quiet solar alert is still in progress, but that may change soon because the Sun is becoming active on the side that we do not see visually from Earth, but that now is watched full time by the Stereo pair of satellites .
Send your signal reports, comments about the program and radiohbby related questions to inforhc at enet dot cu, or VIA AIR MAIL to Arnie Coro, Radio Havana Cuba, Havana , Cuba