Dxers Unlimited middle of the week edition for Tuesday 2 May 2017
By Arnie Coro
radio amateur CO2KK
Hola mis amigos radioaficionados now listening to the middle of the week edition of Dxers Unlimited... this is certainly the one and only radio hobby program that attempts to cover each and every one of the more than 90 ways of enjoying this wonderful way of spending our spare time having a lot of fun with our radios....
India is at the forefront on the use of Digital Radio Mondiale technology. The current test period includes one hour a day of DRM broadcasts at twenty five different transmitting stations.... But the single most important drawback to DRM Digital Radio Mondiale continues to be the lack of low and medium cost eceivers that are still sadly missing .... Another recent news item brought information about an integrated circuit capable of demodulating all possible transmission modes, including standard AM, FM, and several of the already on the air digital radio modes, like DRM, the IBOC or HD Radio and all different DAB modes....
Massive production of this new digital integrated circuit that automaticallly detects the modulation mode in use , producing clear audio output, could be the breakthrough every one is expecting in order to introduce the most efficient digital modes at a worldwide scale.... In the meantime, DRM capable receivers continue to be expensive, while those for HD Radio and DAB are slowly becoming available at lower cost... More updates about digital radio transmission modes at an upcoming edition of Dxers Unlimited.
Item two: Coming to you from Dxers Unlimited's middle of the week edition... a short form solar activity update.... The Sun is going through another period of very low activity, and just three sunspot active regions with a single sunspot inside are visible, so the current sunspot number was 33 late Monday UTC day...
Item three one of the show... Si amigos, many of you I am sure will want to experience the unique joy of listening to a radio receiver that you have just built... I can share with you my very special day , way back in 1956 when the radio in kit form that was my birthday present started to pick up station CMZ on one thousand ten kiloHertz, and at the low frequency end of the little radio's dial I was listening to CMQ's powerful signal on 630 kiloHertz...The radio used just a single 3S4 miniature triode... and was powered by two batteries.... a one point
five volts size D cell for the vacuum tube's filament and a twenty two and a half volts battery for feeding the plate voltage for the 3S4. The receiver used a classic regenerative circuit using the Armstrong plate feedback method, controlled by a variable capacitor throttle control...
It took me a while to understand how the radio could be made more and more sensitive until it starting howling like a lone wolf ... the howl audio note was bad for my ears !!! Then about a week after using the radio , one evening , while tweaking the throttle regeneration capacitor just at the point before the radio started to oscillate , a weak signal arount the center of the dial could be heard and it was a station speaking in English.... Si amigos, yes my friends, oui mes amis, that was KAAY , from Little Rock in Arkansas on 1090 kiloHertz, and just at
slightly higher frequency the scond DX station was coming in... it was WBT from Charlotte North Caroline on 1110 kiloHertz, and I kept the radio going from one station to the another until about three o'clock in the morning... Needless those two first AM Broadcast Band stations picked up by very simple battery powered regenerative receiver turned me into a lifelong fan of AM Band Dxing.... Oh, and before I forget, the radio can be built nowadays , because it uses very common parts that are still available....
Si amigos, you are listening to Radio Havana Cuba, this is our middle of the week edition of Dxers Unlimited, I am your host Arnie Coro, radio amateur CO2KK, and now more about home brew radios, that use a low number of parts and can be built at home with a few hand tools, a low wattage soldering iron and a low cost digitalmultimeter...
You must learn how to identify electronic components like resistor, capacitors, transistors, integrated circuits and vacuum tubes pin outs.... It will take some time, and you will want to obtain the help of more experienced radio hobby enthusiast ....buy be assured it can be achieved and after some time your know how will be enough for you to build your first simple radio...
My advice is to try to build a simple crystal receiver to which you add a one or two transistors audio amplifier so that good headphone volume can be achieved from the local and near local AM broadcast band stations....
Item four: More information about the spring and summer sporadic E layer propagation season, just starting at this moment. According to several ionospheric propagation experts, they expect this year's sporadic E main season spanning from early May to late July could be surprisingly active... The gurus say that there seems to be a reverse connection between solar activity and the sporadic E layer events...
In other words during solar minimum years it seems that less solar activity
somehow helps to enhance the probability of the formation of high ionization density patches at the height of the E layer that may produce outstanding propagation events... Amateur radio operators having stations capable of operating on the 10 and 6 meter bands will be able to make DX contacts on those two bands during the summer Sporadic E season now starting... The real challenge brought by Sporadic E layer events is that so far they have proven to be impossible to predict... so far there is no method that can tell in advance when one of such super density sporadic E layer patches starts suddenly brings in DX signals for periods as short as a few minutes or maybe even hours and then
suddenly just vanish...
For 6 meters band operators the sporadic E events make possible working DX stations several hundreds of miles away, with the first skip zone area coming after a zone of no signals... There is also the possibility of double and triple hop skip signals when two or three patches of high density sporadic E clouds align themselves properly...
Si amigos, we will soon learn if the forecasts of a very active sporadic E layer Dx season is going to happen or not... and if you do have a nice FM broadcast band radio it would be possible during very good band openings to pick up far away FM stations via sporadic E very high density patches to raise the maximum usable frequency past the one hundred megaHertz band.
And now at the end of the program here is our propagation update and forecast for the next several days--- solar activity at very low levels, just a lonely weak sunspot active region in sight Tuesday morning local time in Havana, around 12 hours UTC... a quiet ionosphere due to the very low ultraviolet radiation levels, so the maximum usable frequency reached by the best North to South propagation paths will barely reach 20 megaHertz at peak times... Be on the look out for sporadic E openings... it is now clear that the late spring and summer E skip season is well under way...
I am already receiving reports from Six Meters Band radio amateur operators from North America and the Caribbean telling me that they have already made the season's first E skip contacts...
AMIGOS please don't forget to set aside a little time to send me a signal report and your most appreciated comments and radio hobby related questions to Dxers Unlimited. Send mail to inforhc@enet.cu .
Postal Mail: Arnie Coro, Radio Havana Cuba, Havana , Cuba