By Arnie Coro, VO2KKHi amigos radio-aficionados !!!! Welcome to the mid week edition of your favorite listener oriented radio hobby show VIA SHORT WAVE, also visible at our website on World Wide Web too by going to http://rhc.cu ...
I am Arnie Coro, radio amateur CO2KK, your friend here in Havana and host of this twice weekly program, entirely, absolutely devoted to our wonderful and fascinating hobby ...RADIO...
At the moment that you are hearing this program radio amateur operators in four Caribbean nations are already providing emergency communications as Hurricane Gustav,the seventh storm of this season is moving towards Haiti and Cuba. Amateurs in the Dominican Republic,
Haiti, Jamaica Cuba with the help of operators in Mexico, Honduras , Guatemala and the United States will be handling any emergency related traffic, and also providing the national weather services with the most up to date data registered at their locations.
Cuban amateurs in particular have already deployed portable stations at several remote locations in the mountains of eastern Cuba, where past experience has shown that rivers overflowing their banks due to the heavy rains that accompany tropical storms and hurricanes.
You can pick up hurricane related amateur radio communications on the 20, 40 and 80 meter bands.
The Cuban emergency nets operate on 7045, 7060 to coordinate with Mexico, 7080 and 7110 on 40 meters and at night stations operate on 3740 kiloHertz on the 80 meters band. The Hurricane Net frequency on 20 meters is 14325, and it is active whenever a tropical storm or hurricane is near land.
And NOW, after this Hurricane Gustav update here is the rest of menu for today amigos...
Item one: Yes , an extremely low parts count amateur radio transmitter that works nicely and is even simpler than the ONE PLUS ONE rig we described here recently... this one is still simpler and I already have made several CW radiotelegraphy contacst with it...
Item two: The ONE PLUS ONE rig continues to bring in feedback from Dxers Unlimited’s fans...
A Canadian listener sent me an enthusiastic e-mail about his success with the simple ham radio rig, and he is going to add a keyer to it...
Item three: Antenna topics section will be devoted today, again, at the request of several listeners , to the half square for the two meter band, an antenna that you can homebrew using readily available materials ...
Our popular you have questions and Arnie answers them section , la NUMERO UNO, the most popular section of the program will deal today with the design of new buildings and how architects and engineers seem to be forgetting that people using those buildings do want to listen to the radio too !!!
And as always at the end of the show, Arnie Coro’s Dxers Unlimited’s HF propagation update and forecast will provide you with short wave radio’s must up to date information in an easy to understand way, so that you can enjoy radio a lot more...
Jose Costa Pupo is my sound engineer here today, we are working here at RHC studio number 6
The ONE PLUS ONE, the amateur radio transmitter built using just one integrated circuit and one NPN power output transistor has proven to be quite a success among Dxers Unlimited’s fans that are also amateur radio operators...
The straightforward design can be implemented using the very easy to assemble so called ¨¨dead bug¨¨ type of construction, that is by just gluing the integrated circuit and transistor upside down , with the connecting legs facing up, to a piece of copper foil printed circuit board.
The pc board acts as a ground plane to which you solder the parts that connect to ground, and wiring is extremely simple, not requiring artwork or the messy chemicals needed for the production of homebrew printed circuit boards...
My prototype ONE PLUS ONE , is now operating on the 40 meters ham band, thanks to a friend that gave me a nice quartz crystal that resonates very near to the lower edge of the band, on 7006 kiloHertz...
The 40 meters band version of the ONE PLUS ONE, keys very well, and is providing about 3 watts output into my wideband FAN DIPOLE antenna...
So far I have made just a few contacts with stations in the United States and Canada, no Europeans or Asian stations yet, but the reports received tell me that as soon as HF propagation conditions get better, the little rig is going to bring in some nice transatlantic DX too.
NOW, let me tell you what happened last Sunday... a friend visited me, and saw the ONE PLUS ONE, and I had no choice but to give him a 7400 digital integrated circuit that I had removed from an old computer card, and also provide him with a few more parts to complete the kit of components for his ONE PLUS ONE.
He went home and Monday evening, he was on the phone asking me to tune around 7050 kiloHertz because his ONE PLUS ONE was already on the air...
We had a nice two way CW QSO using ONE PLUS ONES at both ends, and then he asked if I could design a circuit that could beat the ONE PLUS ONE , that is, using still fewer electronic components...
Well Orlando, I told him, I think it can be done...
And late Monday evening I had the one transistor , 2 resistors, 1 fixed and 1 variable capacitor rig on the air on the 40 meters band...
YES amigos, you heard it right, just one transistor, two carbon resistors, one disk ceramic capacitor, a variable capacitor from an old radio, plus a quartz crystal and a homebrew coil wound on an empty pills plastic container....
The rig was also wired dead bug style on a small piece of PC board,and the tests were carried on by powering it from my workbench variable voltage power supply...
In this case , and once again I used a transistor that was removed , that is recycled, from a dead computer MFM legacy disk drive , and the coil form was a discarded medicine pills plastic container... plastic of course....
I wound 20 turns of no 20 enamelled wire, with a tap at 7 turns for the transistor and then wound a 4 turn link on top of the bottom of the 20 turns coil...
When connected to the CO2KK broadband antenna, via the antenna tuner, the little rig moved the power meter needle to around 1.5 watts, and sure enough, a Cuban station heard my CQ and came back to me during this first test...
So, now you know that with still fewer parts one can make a useable ham radio transmitter....
No amigos it won’t be a record breaker, and I am afraid that you won’t win a DX contest with it, but, its so easy to build and to operate that I am sure many of you will like to have the circuit diagram and building instructions for the ONE T ONLY rig, a single one power output transistor rig that so far I have tested on 160 80, 40 and 30 meters ... and of course that I will send you the complete set of data for winding your coils for those 4 bands...
Send your request for the ONE T ONLY single transistor amateur radio transmitter to inforhc at enet dot cu, again , it´s very easy to remember, inforhc at enet dot cu, and don’t forget to include a signal report and comments about the show, as well as any suggestions or new ideas you may want to include in our program...
If you are not yet in cyberspace,send your request via AIRMAIL to Arnie Coro, Radio Havana Cuba, Havana , Cuba....
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The now becoming more and more popular among HF bands Dxers… The HALF SQUARE vertical wire antenna can be easily adapted for the 2 meter amateur band. The 2 meter HALF SQUARE is very easy to homebrew, and among its significant advantages is the fact that if you go exactly by the measurements provided by us, you won’t need a VHF standing wave ratio meter to adjust it...
Of the more than twenty HALF SQUARE two meter band antennas built here by radio amateurs, not a single one has required absolutely any adjustments...but as a precaution we have always checked them using a professional standing wave ratio meter and antenna analyzer, the fact is that they all came up with a very low standing wave ratio...
The two meter band HALF SQUARE is fed using 50 ohm coaxial cable and an easily built coaxial choke balun to decouple the antenna from the coaxial downlead...
The two vertical elements of the antenna are 56 centimeters long each, and the horizontal wire that connects them is 94 centimeters long...
The center of the coaxial cable connects to the base of one of the two vertical elements,
and the braid or shield of the coaxial cable connects to the horizontal wire that goes to the base of the other vertical antenna.
I have used properly painted plywood as the support for the antenna, but it is better to use white PVC pipe, because it will last longer.
The plywood supported version of the HALF SQUARE for two meters was the first prototype and we had to use it during one of last year’s hurricane, when our Radio Club was asked to provide communications at a location where the sea wall usually is jumped by huge waves and that part of the city floods in a very short period of time...
As always, with all Dxers Unlimited’s radio hobby projects, complete, detailed building instructions are freely available, and you can be sure that each and every circuit and antenna mentioned here at our Dxers Unlimited program was fully tested before it was made available to our worldwide audience...
As a very good friend and long time listener of our show likes to say, you can’t go wrong with Arnie’s radio hobby projects because if you happen to have any doubts, by just sending an e-mail to inforhc at enet dot cu or an AIRMAIL postcard or letter to Arnie Coro, Radio Havana Cuba, Havana , Cuba, I will provide you with a fast reply that will clear up your possible doubts...
The HALF SQUARE two meter band antenna, a very easy to homebrew almost 5 dB gain antenna for your handie-talkie or fixed table top rig, is made using no 10 or no 8 copper wire, a length of PVC pipe and a length of 50 ohm coaxial cable with the antenna connector soldered at one end...If you want to learn more about one of the lowest cost and easier to build 2 meter band vertical antennas...then just send an e-mail to inforhc at enet dot cu or an AIRMAIL postcard or letter to Arnie Coro , Radio Havana Cuba, Havana, Cuba...
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Yes amigos ! Architects and engineers should learn more about radio and TV reception problems that people living in the buildings that they design are having .
According another a very good friend an long time Dxers Unlimited listener from Toronto, Canada , the newer office buildings built there in the past 5 years , do provide a lot of facilities but radio reception inside them is almost impossible, and the same holds for TV sets.
The problem with AM reception can be traced to the use of so called energy saving fluorescent lamps, each of them a wideband pulse transmitter that wipes out reception over a wide band of frequencies...
Short wave receivers , even when located close to the big picture windows are also victims of the many electronic gadgets that form part of the newer buildings,like thermostats, elevator control systems, alarm systems, fire warning systems etc..
And don’t think that office buildings are the only ones where radio reception is becoming next to impossible, modern hotels or those that have recently rebuilt , as well as apartment buildings also have similar problems, as more and more people own home computer systems that use switched mode power supplies, capable not only making a lot of RF noise but also capable of actually distorting the power line waveform beyond recognition, not to mention the terrible spikes generated by the high current devices controlled using state of the art semiconductors....
Not too long ago, a well known Cuban architect was telling me about the so called “intelligent buildings” and I asked him a question that left him scratching his head....
My question was if among the virtues of the “intelligent building” was wiping out their users possibilities of receiving radio and TV signals....You should had seen his face… I certainly left hime thinking !!!
And now amigos, as always, at the end of the show, here is Arnie Coro’s Dxers Unlimited’s propagation update and forecast...
Solar flux still at extremely low levels , solar activity was very low during the whole week and will stay at that level during the next several days... The slow transition to the equinoctial season is now in progress, and you will soon notice that the higher frequency bands will start to behave a lot better as we approach the autoumn equinox...
Best bands for daytime listening continue to be 19 and 16 and , with 16 meters showing a marked improvement during the past several days...
For radio amateurs, 20 metersand also 17 meters will be the best bands to operate during the local daytime hours, with 40 meters providing nice DX even late in the evening...
Solar flux was very near 65 units on Tuesday, and the A index was 2.... I hope to see you at the weekend edition of the show and if you are a radio amateur operator be looking for CO2KK, my ham radio station on the air with the ONE PLUS ONE CW rig very near to 70060 kiloHertz during my local evening hours, from 0200 to 0400 UTC...
Maybe we will soon have a nice two way QSO on 40 meters with the little homebrew wonder transmitter.
And don’t´forget to send me your signal reports and comments about the program amigos !!!
Send mail to inforhc at enet dot cu, or VIA AIR MAIL to Arnie Coro, Radio Havana Cuba, Havana, Cuba
