Re: [HCDX] Dxers Unlimited's mid week edition for 24-25 April 2007

["Prof. Arnaldo Coro Antich" <inforhc@xxxxxxx>]

Radio Havana Cuba
Dxers Unlimited
Dxers Unlimited’s mid week edition for 24-25 April 2007
By Arnie Coro
Radio amateur CO2KK

Hi amigos radioaficionados around the world and in space… this is the 
mid week edition of your favorite listener oriented and technically 
minded radio hobby program… I am Arnie Coro, radio amateur CO2KK, your 
host here for the next seventeen minutes , inviting you to stay with us 
for the most up to date HF plus low band VHF propagation update and 
forecast, and a lot more radio hobby related information…
So, here we go, first things first… the spring – summer Sporadic E 
season has already started, and I am receiving reports from Mexico, 
Central America, the South of the USA and the Caribbean that VHF 
openings reaching well into the FM broadcast band are now happening on 
an everyday basis, having started to occur, according to the reports 
received since last Friday. Scientists don’t know yet what causes 
Sporadic E layer high free electron concentrations that lead to quite 
spectacular DX on frequencies from 25 up to 250 megaHertz. But on a day 
to day basis during the spring-summer Sporadic E DX season; band 
openings between 25 and 100 megaHertz are much more common. As a matter 
of fact, the frequency range between 25 and about 75 megaHertz shows 
much more frequent openings. So, here is your amigo Arnie Coro’s advice, 
monitor the low band TV channels, especially TV stations operating on 
channels 2 and 3 for signs of Sporadic E openings… And if you are a 
radio amateur, and have a rig that is capable of operating on 10 meters 
or on 6 meters, then keep it on scanning the 10 and 6 meter bands for 
signs of skip signals.
As solar cycle 23 is now passing through its minimum, propagation gurus 
believe that this actually helps Sporadic E openings to occur… as there 
seems to be a link between minimum solar activity and the frequency and 
duration of the Sporadic E events…
More about HF propagation conditions at the end of the program…
Now here is item two:
Very low solar activity is also good for AM broadcast band Ding, 
something that I enjoyed Monday evening after the national baseball 
championship game was over. Using my ultra small portable receiver, 
stations from the USA, Mexico, Puerto Rico, Colombia and Venezuela were 
heard here between midnight and about 1 AM local time… Amazing as this 
may sound, the ultra small portable using just a pair of triple A size 
batteries brings in a lot of DX because of the fact that it uses a 
relatively large ferrite rod antenna.
Before going to bed, I ran another AM broadcast band scan from about 1 
AM to 1.30 AM using my homebrew super high gain double conversion 
receiver, and could pick up several heterodynes at the high end of the 
band, indicating the presence of transatlantic signals from Europe …
Si amigos, yes my friends, oui mes amis… AM broadcast band Dxing is 
still peaking, despite the fact that the spring equinox happened a month 
ago… As a good friend of mine that loves Dxing on the AM band likes to 
say… there is nothing better for that band than very low solar activity 
that comes together with very quiet geomagnetic conditions…
Stay tuned for more radio hobby related information, as the mid week 
edition of Dxers Unlimited continues in a few seconds, after a short 
break for station ID.
I am Arnie Coro in Havana, and my e-mail address is arnie@xxxxxxx

…….

You are listening to Radio Havana Cuba, soon to be celebrating its 46th 
birthday… Yes amigos, on the first day of May of 1961, our station went 
on the air as Radio Havana Cuba, and that’s why we will be celebrating 
46 years on the air… From February 24th of 1961 until May first of that 
year, we were on the air using the name Cuban Experimental Short Wave, 
or in Spanish, Onda Corta Experimental Cubana… Now here is item three of 
today’s program… ASK ARNIE, the number one most popular section of the 
show… according to the e-mail messages, letters, and whenever I have the 
nice opportunity of talking to Dxers Unlimited’s listeners on the air 
while operating on the amateur bands. Unfortunately, at this solar 
minimum, short wave propagation conditions are very poor, especially for 
low power amateur radio stations… But the good news is that scientists 
are expecting solar activity to start moving up fast by the end of the 
year, and that will mean that next spring HF propagation conditions are 
going to be much better… By the way, you have just heard the answer to a 
question sent by listener Carlos from Mexico City, who asked in his 
e-mail to arnie@xxxxxx, when solar activity of the new cycle will begin 
to move up, and how fast this is going to happen…
Again, expect the solar “numbers” to start climbing by the end of 2007 
and be well on their way to much better figures about a year from now… 
In the meantime, do as I do, and keep those radios on especially around 
your local sunset, when propagation conditions are better than at any 
other time of the day…
Item four:  A quick visit to Arnie’s workshop, where yet another SUPER 
ISLANDER homebrew amateur radio transceiver is in the works… This 
version of the SUPER ISLANDER is a hybrid, using both solid state and 
vacuum tube components and it is a GREEN RADIO…. You know why amigo 
Jose, CO2JA described it as a GREEN RADIO… well, because it uses 100 
percent recycled components, that otherwise in most cases will end up 
polluting landfills… The SUPER ISLANDER is an optimized version of the 
original ISLANDER double side band and CW transceiver designed by amigo 
Pedro Rodriguez, CO7PR from Ciego de Avila province in central Cuba. 
Pedro designed the ISLANDER so that young radio amateurs that had taken 
their ham radio license tests and had no rigs, could build the ISLANDER 
and go on the air on 40 meters.
The project has proven to be not only extremely popular among newcomers 
to the hobby, but also among many old timers that after hearing them on 
the air, decided to start collecting the parts to homebrew their own 
ISLANDERS , to be used as a standby transceiver or for portable work. 
During the frequent tropical storms and hurricanes that get near to Cuba 
or go across our archipelago, one can frequently hear the ISLANDERS and 
SUPER ISLANDERS on the air on 40 and 80 meters passing weather related 
and emergency traffic. Running between 20 and 50 Watts, these radios are 
very rugged, can be easily repaired with standard tools and common test 
instruments, and when connected to a Near Vertical Incidence Sky wave 
type of antenna , they provide excellent emergency communications within 
a radius of between 10 and 500 miles, exactly what we need here for our 
emergency amateur radio networks. The fact is that the original CO7PR 
has evolved into a still easy to build with locally available parts 
single band transceiver, that Cuban radio amateurs keep home brewing and 
using despite the availability of much more modern multi-band 
transceivers, because as someone was commenting during the weekend over 
the air, there is nothing that can be compared to working a DX station 
with a radio that you have built yourself!!! And YES, I fully agree with 
that remark amigos!!!

……

Dxers Unlimited’s mid week edition coming to you from Havana… via short 
wave on 9550 kilohertz from 23 to 00 hours UTC… Yes you can also listen 
to this program on the 31 meters band when Radio Havana Cuba’s English 
language program to the Caribbean and Southern United States of America 
is on the air on 9550 kilohertz with 100 kilowatts and our 6 dB gain 
omni directional antenna…
And of course, that if you have Internet connectivity, you can also 
listen to our English program from 05 to 07 UTC by visiting our website 
rhc.cu, again, rhc.cu and clicking on the loudspeaker icon at the top of 
the page…
Now here is item five of today’s program> More about the SUPER ISLANDER 
double side band and CW transceiver, that now has a much better receiver 
thanks to the use of triple tuned band pass input filter… The signal 
from the antenna is fed to a very simple, but also very effective radio 
frequency attenuator… and then it goes through an easy to homebrew 
triple tuned band pass filter…The filter was designed so as to limit the 
pass band response to just 200 kilohertz, effectively removing other 
signals from the radio frequency amplifier stage. The SUPER ISLANDER 
receiver is something quite unusual according to today’s design 
standards, because it is a vacuum tubes direct conversion radio… The 
loss introduced by the triple tuned filter is compensated by the RF 
amplifier stage that feeds a vacuum tube product detector…As you may 
realize most of the receiver’s gain is obtained at the audio frequency 
section, so one most follow good audio circuits construction practices… 
The SUPER ISLANDER uses regulated and very well filtered DC, that is 
direct current on the filaments of the product detector and the first 
audio amplifier stage, and that has proven to be quite an improvement 
over the original ISLANDER, that required the use of small coupling 
capacitors between the audio stages to remove the low frequency hum that 
was always present in the background of the received signals. The SUPER 
ISLANDER receiver is not as sensitive as a thousand dollars amateur 
bands transceiver, but all I can tell you is that Cuban several Cuban 
radio amateurs have already achieved DXCC, that is worked more than 100 
countries or DX entities as they are now known, using both the ISLANDERS 
and SUPER ISLANDERS on the 40 meters band…
Si amigos, low cost, homebrew radios for the enjoyment of our wonderful 
hobby can be designed and built… the ISLANDERS and SUPER ISLANDERS are a 
good example of what can be achieved by clever use of hybrid circuits, 
recycled components and ham radio ingenuity…
And now as always at the end of the program, here is Arnie Coro’s Dxers 
Unlimited’s HF plus low band propagation update and forecast… Here are 
the predictions for 25 Apr 2007 10CM FLUX: 070 /, geomagnetic 
disturbance indicator nice and low AP: 007
Now the predictions for 26 Apr 2007 10CM FLUX: 070 / with slightly 
higher Planetary an index expected to reach: 010
Solar activity is expected to be low during the next 48 hours.
Geomagnetic activity is expected to be mostly quiet with a risk of
Isolated unsettled conditions as the Earth is within a high-speed solar
Wind stream from a coronal hole. The solar wind speed as measured by the 
ACE spacecraft is however moderately high with values around 400 km/s.
Now, something that is becoming quite common during this solar minimum: 
ZERO SUNSPOTS… a BLANK SUN, and the
WOLF NUMBER CATANIA    : 000
Expect some nice Sporadic E openings to happen between 7 AM and 11 AM 
local time, with a second round from about 3 PM to 8 PM local time… See 
you all at the weekend edition of Dxers Unlimited amigos, and don’t 
forget to send me your comments about the program and radio hobby 
questions… mail to arnie@xxxxxx , or VIA AIR MAIL to Arnie Coro, Radio 
Havana Cuba, and Havana, Cuba

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