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By Arnie Coro
radio amateur CO2KK
Hi amigos radioaficionados around the world and orbiting planet Earth … I am your host Arnie Coro, radio amateur CO2KK happy to have you listening to the mid week edition of Dxers Unlimited, now in its short format 10 to 12 minutes version, especially designed to fit into our new one hour news and information format.
As expected, I have received several e-mail messages from listeners that want to have the show back to its long form 18 minutes format, something that at the present time is not possible... but that maybe in the not too distant future we may have it available again, at least during the weekend edition, the one that according to audience research statistics is heard by a larger number of radio hobby fans worldwide.
In the meantime, let's optimize this format, so that more radio related information may go on the air on each program. Here is item one: another upsurge of solar activity , but as previous ones of the solar cycle 24 , it didn't last long... expect very low solar activity to prevail during the rest of the week, it no new active sunspot regions suddenly appear on the solar disc.
Item two: The weekend VHF ham radio contest did not enjoyed good sporadic E openings here in the Caribbean... I monitored the 6 meters band and heard very few stations during two brief openings , one happening late Saturday afternoon and the second one on Sunday morning.
Item three: Experiments with the Polyakov harmonic mixer detector, the amazing circuit that makes possible homebrewing a very simple , easy to assemble ham bands radio receiver, have demonstrated that the four diodes version outperforms the two diodes classical circuit in a very signficant way.
Direct conversion or homodyne receivers are about the easiest to homebrew and provide much more reproducible results than regenerative receivers. Stay tuned for more radio hobby related information coming to you from Havana … I am your host here , Arnie Coro , radio amateur CO2KK back with you in a few seconds, after a short form station ID
…...................
This is Radio Havana Cuba, the name of the show is Dxers Unlimited, and it can be heard twice weekly, now every hour all along our broadcast segments . Dxers Unlimited used to be on the air once every two hours of our English language broadcasts, but now that we are transmitting one hour
the program goes on the air every hour , just after the half hour news bulletin... and you can also read the scripts of the show and see some interesting photos about solar activity by visiting http://dxersunlimited.blogspot.com , again the URL for our Dxers Unlimited blog is http:///dxersunlimited.blogspot.com.
You can send your signal reports and comments via e-mail to inforhc at enet dot cu , or leave your comments at the Dxers Unlimited's blog …
Now here is item four: Our technical topics section today is devoted to the results of some recent experiments done in my workshop, in order to compare the results between two direct conversion receivers … one using a two diodes antiparallel harmonic detector, also known as the Polyakov mixer, and the other one using four diodes...
Results were very consistent and showed that using the four diodes version of the Polyakov mixer provides significantly better weak signal results... so , at the cost of just two inexpensive switching diodes, your radio is going to be a much better perfoming receiver...
Item five: Short form antenna topics section, that today will also provide test results after running several experimental setups with a 20 meters band vertical antenna... Measurements done using 4 and 8 elevated radials showed practically no difference of the field intensity at about 2 miles from the antenna...
When the 4 elevated radials were removed and replaced by 16 roof surface mounted radials, the signal received by the station at the other end of the test went down significantly... Results achieved by recent medium wave AM broadcast band transmitting installations using 4 elevated radials replacing the classic 120 quarter wave radials layed at about six inches or 15 centimeters into the soil, are making a great impact on the AM station's engineers that may soon start removing the 120 ground mounted radials, selling the valuable copper as scrapt metal and replacing them with 4 or maybe up to 8 elevated radials.
According to a recent trade magazine article, elevated radials may soon become as popular as the folded grounded monopole antennas that are now used by many AM stations in order to be able to rent tower space to other telecommunications services.
….........................
Si amigos, the summer is here, and we are just a few days away from the summer solstice, when the number and duration of the sporadic E events is higher than at anytime of the year. Tuesday morning as I was writing the script of the show, my local TV Channel 2 station in Havana,
TeleRebelde was getting a lot of venetian blinds type of co-channel interference from an unidentified station that at time overrides the audio from the local channel two.
All I can say is that the station causing the interference is using the NTSC analog TV transmission standard , so it is not located in the USA, where all high power VHF stations are broadcasting using the digital TV standard ATSC...
A few minutes after the interference began, I started to pick up a 6 meters band beacon from Mexico, so it seems like the band opening is in that general direction...
The maximum useable frequency curve at half past ten in the morning local time in Havana was reaching well past 75 megahertz, as the local channel 4 station, Canal Educativo was also receiving co-channel interference , possibly from Mexico too...
But a quick scan of the FM broadcast band showed no signs of DX stations coming in, although as the Sun moved higher up, the possibilities of a nice FM band E skip opening were higher...
Now amigos, just before going QRT, here is Dxers Unlimited's HF propagation update and forecast... a high speed solar wind will be disturbing the ionosphere for the next 48 to 72 hours, while the solar flux moves down because the active sunspot regions in sight are decaying, so expect rather poor propagation on the bands above 14 megaHertz at least until the weekend...
Don't forget to send your signal reports and comments about this and other RHC programs to inforhc at enet dot cu, and VIA AIR MAIL to Arnie Coro, Radio Havana Cuba, Havana, Cuba
radio amateur CO2KK
Hi amigos radioaficionados around the world and orbiting planet Earth … I am your host Arnie Coro, radio amateur CO2KK happy to have you listening to the mid week edition of Dxers Unlimited, now in its short format 10 to 12 minutes version, especially designed to fit into our new one hour news and information format.
As expected, I have received several e-mail messages from listeners that want to have the show back to its long form 18 minutes format, something that at the present time is not possible... but that maybe in the not too distant future we may have it available again, at least during the weekend edition, the one that according to audience research statistics is heard by a larger number of radio hobby fans worldwide.
In the meantime, let's optimize this format, so that more radio related information may go on the air on each program. Here is item one: another upsurge of solar activity , but as previous ones of the solar cycle 24 , it didn't last long... expect very low solar activity to prevail during the rest of the week, it no new active sunspot regions suddenly appear on the solar disc.
Item two: The weekend VHF ham radio contest did not enjoyed good sporadic E openings here in the Caribbean... I monitored the 6 meters band and heard very few stations during two brief openings , one happening late Saturday afternoon and the second one on Sunday morning.
Item three: Experiments with the Polyakov harmonic mixer detector, the amazing circuit that makes possible homebrewing a very simple , easy to assemble ham bands radio receiver, have demonstrated that the four diodes version outperforms the two diodes classical circuit in a very signficant way.
Direct conversion or homodyne receivers are about the easiest to homebrew and provide much more reproducible results than regenerative receivers. Stay tuned for more radio hobby related information coming to you from Havana … I am your host here , Arnie Coro , radio amateur CO2KK back with you in a few seconds, after a short form station ID
…...................
This is Radio Havana Cuba, the name of the show is Dxers Unlimited, and it can be heard twice weekly, now every hour all along our broadcast segments . Dxers Unlimited used to be on the air once every two hours of our English language broadcasts, but now that we are transmitting one hour
the program goes on the air every hour , just after the half hour news bulletin... and you can also read the scripts of the show and see some interesting photos about solar activity by visiting http://dxersunlimited.blogspot.com , again the URL for our Dxers Unlimited blog is http:///dxersunlimited.blogspot.com.
You can send your signal reports and comments via e-mail to inforhc at enet dot cu , or leave your comments at the Dxers Unlimited's blog …
Now here is item four: Our technical topics section today is devoted to the results of some recent experiments done in my workshop, in order to compare the results between two direct conversion receivers … one using a two diodes antiparallel harmonic detector, also known as the Polyakov mixer, and the other one using four diodes...
Results were very consistent and showed that using the four diodes version of the Polyakov mixer provides significantly better weak signal results... so , at the cost of just two inexpensive switching diodes, your radio is going to be a much better perfoming receiver...
Item five: Short form antenna topics section, that today will also provide test results after running several experimental setups with a 20 meters band vertical antenna... Measurements done using 4 and 8 elevated radials showed practically no difference of the field intensity at about 2 miles from the antenna...
When the 4 elevated radials were removed and replaced by 16 roof surface mounted radials, the signal received by the station at the other end of the test went down significantly... Results achieved by recent medium wave AM broadcast band transmitting installations using 4 elevated radials replacing the classic 120 quarter wave radials layed at about six inches or 15 centimeters into the soil, are making a great impact on the AM station's engineers that may soon start removing the 120 ground mounted radials, selling the valuable copper as scrapt metal and replacing them with 4 or maybe up to 8 elevated radials.
According to a recent trade magazine article, elevated radials may soon become as popular as the folded grounded monopole antennas that are now used by many AM stations in order to be able to rent tower space to other telecommunications services.
….........................
Si amigos, the summer is here, and we are just a few days away from the summer solstice, when the number and duration of the sporadic E events is higher than at anytime of the year. Tuesday morning as I was writing the script of the show, my local TV Channel 2 station in Havana,
TeleRebelde was getting a lot of venetian blinds type of co-channel interference from an unidentified station that at time overrides the audio from the local channel two.
All I can say is that the station causing the interference is using the NTSC analog TV transmission standard , so it is not located in the USA, where all high power VHF stations are broadcasting using the digital TV standard ATSC...
A few minutes after the interference began, I started to pick up a 6 meters band beacon from Mexico, so it seems like the band opening is in that general direction...
The maximum useable frequency curve at half past ten in the morning local time in Havana was reaching well past 75 megahertz, as the local channel 4 station, Canal Educativo was also receiving co-channel interference , possibly from Mexico too...
But a quick scan of the FM broadcast band showed no signs of DX stations coming in, although as the Sun moved higher up, the possibilities of a nice FM band E skip opening were higher...
Now amigos, just before going QRT, here is Dxers Unlimited's HF propagation update and forecast... a high speed solar wind will be disturbing the ionosphere for the next 48 to 72 hours, while the solar flux moves down because the active sunspot regions in sight are decaying, so expect rather poor propagation on the bands above 14 megaHertz at least until the weekend...
Don't forget to send your signal reports and comments about this and other RHC programs to inforhc at enet dot cu, and VIA AIR MAIL to Arnie Coro, Radio Havana Cuba, Havana, Cuba
Source: Dxers Unlimited: Dxers Unlimited mid week edition15'16 June http://bit.ly/d70FIo
(Yimber Gaviria, Colombia)
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