Radio Havana Cuba

Dxers Unlimited

Dxers Unlimited’s weekend edition for 19-20 January 2008 By Arnie Coro Radio amateur CO2KK

I am Arnie Coro,radio amateur CO2KK , your friend here in Havana and host of this twice weekly 17 minutes on the air , and on also the web

>from 05 to 07 hours UTC ,devoted to our wonderful hobby , yours and

>mine

: RADIO.

Here is item one: The forecast about solar activity you heard during the mid week edition is holding up pretty well, and solar activity continues to be very low, with the ionospheric absorption index reaching also rather low values... Solar flux is hovering around … 70 to 75 units. , and the sunspot count has stayed at extremely low levels,

actually at ZERO , no sunspots for the past 7 days in a row!………...

Item three: Those Dxers Unlimited's listeners that have built different versions of the Micro Vert ultra compact HF antenna have sent e-mail messages telling me that the antenna is providing good reception of the adjacent international short wave broadcast bands, next to the amateur band for which the Micro Vert was actually designed and built r... For example, the 20 meters band Micro Vert, a controversial antenna design by any standards, is providing good reception of both the 19 and the 22 meter shortwave broadcastdo bands, while at the same time letting the owner both monitor and also transmit on 20 meters...although all users report that signals transmitted using the MicroVert are from minus 6 to minus 10 dB below a standard half wave reference dipole.

The 30 meters band Micro Vert is providing, again according to reports received here from listeners that have built them, good reception on the

31 and 25 meters international short wave broadcast bands.... And that's something nice to know, because many of those who have built these antennas tell me that the Micro Vert was the easiest to build and lowest cost solution to the challenge of installing a short wave antenna at a location with very restricted space space available for a short wave antenna... This is a very small antenna, that can be installed almost anywhere… Item four: Changing his radio’s power source from a wall wart plug power supply to a very well built, fully filtered and regulated DC supply changed the way a Dxers Unlimited's listener receiver worked.

Listener Adrian from the UK wrote: " Arnie ,following your advice I read on one of your show's old scripts, I decided to replace the wal wart 9 volts DC supply that I have used with my solid state radio for years. Now your well designed, fully filtered and well regulated KK-12 is making a tremendous DIFFERENCE !!!

Reception is much better, the audio is coming with less distortion and reception of single side band signals on the amateur bands is also much improved... Well Adrian, another Dxers Unlimited listener, amigo Augusto

>from Naples, Italy, did exactly the same thing ahead of you, and now

its, nice to hear about another success story using the KK-12 power supply , and I do hope that many Dxers Unlimited's listeners around the world will hear this show and replace those low quality,poorly regulated and badly built WAL WART DC power supplies with a well designed one like the KK-12...You can be sure that it is a well worth effort amigos !!!

Today here at Dxers Unlimited we will also provide you with our technical topics section, also la numero uno ASK ARNIE, and at the end of the program, our exclusive and not copyrighted HF plus low band VHF propagation update and forecast.

Standby now for a few seconds, the show will continue after a brief musical interval

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This is the weekend edition of Dxers Unlimited, and here is a brief comment about the much improved quality of reception achieved by Radio Rebelde Tropical band broadcast on 5025 kiloHertz with their new antenna... You can send your reports directly to Radio Rebelde ,Send your Radio Rebelde's Tropical Band reports ,Radio Rebelde DX, PO BOX

6277 Havana, Cuba...

PO BOX 6277 Havana, Cuba...

And now here is our technical topics section for today...

How to choose the right type of coaxial cable for your antenna system...

so that you won't waste money buying expensive cables when you really don't need them...

For example, TV cable companies use several types of 75 ohm coaxial cables that are ideal for amateur radio and short wave listening use, as well as for VHF band scanning... Because the world's production of TV type 75 ohm coaxial cable is so huge as compared with the production of 50 ohm impedance cable, 75 ohm coax is much cheaper while providing the same or even higher quality on a per unit length cost basis. That's why I use 75 ohm cables at my amateur radio station for practically all applications... and I can assure you that receivers won't see any difference at all, and in the case of transmitters , a very simple impedance adapter is needed only with solid state outpur transceivers or transmitters, it is the only additional thing needed... My old vacuum tube transceiver, a Kenwood TS820, doesn't even need the impedance converter , as it happily runs with 75 ohm coaxial cables easily matched by the rig’s output stage PI network. Si amigos,yes my friends, oui mes amis... whenever you have a chance of obtaining 75 ohm coaxial cable,just grab it !!! It works quite well, and for all practical purposes, it will do the job.. There are even some large diameter low loss 75 ohm cables used by the TV cable industry that will make ideal transmission lines for your VHF , UHF and low band microwave antennas, and typically the TV cable company technicians will gladly provide radio amateurs with the short ends of the big drums of cable !!!

See, amateur radio and short wave listening don't need to be an expensive hobby if you follow your friend Arnie Coro's advice !!!

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This is Radio Havana Cuba, the name of the show is Dxers Unlimited,and amigos I am very happy to say that we are operating our 100 kiloWatt shortwave transmitters during our nightly broadcasts on the following frequencies, 11760, 9600 and 9550, 6060 and 5965 kiloHertz ... Of those five frequencies only 6060 is in English beaming to the East Coast of North America,, and the other four are broadcasting our Spanish language program to Latin America, so if you want to polish your Spanish, pick them up and enjoy our nightly magazine show to Latin America and the Caribbean amigos !.

You can send your signal reports to me and I will relay them to our Chief Engineer ,and to our transmitting station staff for them to enjoy... Send your signal reports and comments about the audio quality too to arnie@rhc.cu, again arnie@rhc.cu, or VIA AIR MAIL to Arnie Coro, Radio Havana Cuba, Havana, Cuba...

Now here is ASK ARNIE, la numero uno, the most popular section of Dxers Unlimited according to the recent listener survey carried on by our correspondence department’s English secretary Irma Veitia... Today's question... came from a listener in Spain... it says: Dear Arnie, I have recently read more here about the so called broadband over the power lines , BPL. Or PLC, Power Line Communications.. and would like to hear your opinion about that system...

Well amigo, so far all I have heard about BPL or PLC , whichever way you like to call it, or technically speaking making digital broadband connectivity available using the electrical power distribution network ,in its present form it is really dreadful to say the least... In other words, the BPL or PLC systems with today’s available technology so far tested do cause a terrible amount of interference to the radio spectrum used for radio broacasting, communication systems and other applications between 2 and 150 megaHertz... BPL systems have another weakness too, and that is that radio signals from stations operating nearby bring BPL to a complete stop, or reduces the transfer of digital data to a very slow pace...BPL as we know it today is still in its very early stages of development, and things may change one way or the other in the future...

Some researchers are talking about NEW BPL system that will work on the microwave bands. and that one will certainly cause no interference to users of the lower radio frequencies between 500 kiloHertz and 200 megaHertz, that at this moment are in deep trouble if BPL becomes popular !!!

QUESTION NUMBER TWO: It came from a listener in the US state of Nevada... Mark wants to know how the short wave bands will behave from now on, after he heard here last week, that the new solar cycle was just starting. Well amigo Mark, to make a long story short, we are all still watching how the higher frequency amateur bands are now just good for local work, 10 and 12 meters are behaving ,most of the time. like the two meters VHF band, and 15 and 17 meters are opening up for DX for very brief periods as the solar cycle has already reached its minimum and the new one is just beginning. According to the most recent forecasts we will have to wait at least until the end of 2008 to see some worthwhile improvement in short wave propagation conditions, when the sunspots of cycle 24 become plentiful.... So,amigo, here is my advice : keep those long wire antennas up and running , as most of the DX activity will still be concentrating on frequencies spanning form 2 to 10 megaHertz, and sometimes, during your local evening hours this winter, the maximum useable frequency curve will barely reach 6 or 7 megaHertz .!

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And now amigas and amigos, just before going QRT here is our exclusive and not copyrighted HF plus low band VHF propagation forecast...Solar activity is very low, and will almost surely continue at a very low level for the next several days... Solar flux number to be used for short term HF forecasting using propagation analysis software is around

75 units... Expect very good DX conditions on the AM broadcast band, the Tropical Bands on 120, 90 and 60meters and the international short wave broadcast band on 49 meters. Radio amateur operators will enjoy nice DX on 160, 80 and 40 meters during the local evening hours... VHF openings via sporadic E if any , will be almost non existent, and if they happen they will be very short lasting... See you all at the mid week edition of Dxers Unlimited, next Tuesday and Wednesday UTC days, and don't forget to send your signal reports and comments about the program to arnie@rhc.cu via E-Mail, or VIA AIR MAIL to Arnie Coro, Radio Havana Cuba, Havana, Cuba