Radio Havana Cuba
Dxers Unlimited’s weekend edition for Sunday 14 August 2016
By Arnie Coro radio amateur CO2KK
Hi amigos radioaficionados now listening to your favorite radio hobby show… This is Dxers Unlimited .. I am Arnie Coro, your host here at our twice weekly show… Here is item one: A new long range forecast of solar activity is based on advanced research and it calls for an extended period of very low number of sunspots… For most of us casually watching the Sun, activity seems unchanged. But
But if you ask many solar scientists are about what they are doing, the answer will be that they are devoting a lot of time to observe the surface of the Sun where vast explosions and mass ejections are happening.This activity has its origin in intense magnetic fields generated by swirling currents in the sun’s outer layer that scientists call the solar dynamo.
It produces the well-known 11-year solar cycle which can be seen as sunspots come and go on the sun’s surface.
But models of the solar dynamo have only been partially successful in predicting the solar cycle – and that might be because a vital component was so far missing to scientists.
After studying full-disc images of the sun’s magnetic field, Professor Valentina Zharkova of Northumbria University and colleagues, recently achieved what was described as very important discovery in the field of solar research…Professor Zharkova and her group found out that the sun’s dynamo is actually made of two components – coming from different depths inside the sun.
The dynamic interaction between these two magnetic waves either amplifies solar activity or damps it down. Professor Zharkova’s observations suggest we are due for a prolonged period of low solar activity.
She stated that we will see very low solar activity from 2020 to 2053, when the three next cycles will show a very reduced magnetic field of the sun. Basically what happens is these two waves, they separate into the opposite hemispheres and they will not be interacting with each other, which means that resulting magnetic field will drop dramatically nearly to zero. And this will be very similar conditions like what happened during the Maunder Minimum.
And Professor Zharkova emphasized that the upcoming the stage of solar activity will see that the magnetic field of the sun is going to be very, very small.
Finally the well known solar expert suggests it could be a repeat of the so-called Maunder Minimum – a period in the 17th century with little solar activity.
Now we only hope because these upcoming Maunder Minima will be shorter. The Maunder Minimum of the 17th century was about 65 years, the Maunder Minimum which we expect will be lasting not longer than 30-35 years Amigos, although this is just the first analysis of the so called solar dynamo interactions, at present solar cycle 24 is already showing characteristics of a noticeable low activity, in fact the lowest since at least the beginning of the 20 th century and possibly as low as a minimum registered around the year 1880…
Watching the Sun on a day to day basis is showing us the typical peaks and valleys of activity that at this moment are not reaching more than 120 solar flux units…. something that is taking its toll on the HF bands propagation conditions .
My advice to radio amateurs that are participating in contests and other types of activities on the HF bands is to be prepared for operating more on the lower frequency bands. The upcoming Lighthouses and Lightships yearly event held during the third weekend of August is another example when I expect many more contacts on the 160, 80 and 40 meters band to happen, requiring that the participants install antennas for those three bands.
By the way several Cuba special event stations will be on the air during the Lighthouses and Lighships event using the T4, yes the T4 prefix, that is one of the four assigned by the international agreements to Cuba, the other three are CL, CM and CO… So if during the upcoming third weekend of August you happen to pick up stations using the T4, the Tango 4 prefix, you now know they are Cuban radio amateurs on the air…
Stay tuned for more radio hobby related information comming to you via short wave and streaming audio from http://www.radiohc.cu Back in a few seconds after a station ID. I am Arnie Coro, radio amateur CO2KK
short musical intercut
This is Radio Havana Cuba, the name of the show is Dxers Unlimited. ASK ARNIE is the most popular segment of this program… Here I answer your radio hobby related questions sent to inforhc at enet dot cu… Today I am answering to several listeners that are also licensed as amateur radio station operators.
They all want to know what options, if any are available to install antennas for the 160, 80, 60 and 40 meters bands that can fit into limited spaces.
Yes amigos, with the very low solar activity now in progress , there is certainly no choice but to try to install antennas capable of making possible to operate on 160, 80, 60 and 40 meters bands. For all practical purposes I divide my suggestions into two very different approaches… For the 80, 60 and 40 meters bands the use of inductive and capacity loaded antennas can put your station on the air with reasonable efficiency if you happen to have at least 22 meters of available horizontal space for the 80 and 60 meters dual band antenna, and about 12 meters for the 40 meters short dipole.
According to antennas modeling software, the best approach is to use both inductive and capacity loading, making possible to install an antenna that will provide the possibility of operating on the lower frequency bands with a loss of between 3 and 6 dB as compared to a full size horizontal half wave dipole. Even with a 6 dB loss your compact short form horizontal half wave loaded dipole will put you on the air with a signal that will be heard just one S unit below a full size antenna.
In the case of 160 meters, installing an antenna when a limited space is available will be quite a challenge, and here is where the short inductive and capacity loaded vertical antenna comes into play… A large top capacity hat really helps, but the vertical will need a very well laid out ground system. Experimental data that is very well documented shows that a few quarter wave elevated radials will do the work of the classic Doctor Brown’s 120 quarter wave radio buried ground radials… I must add that for DX work, the short loaded verticals with elevated radials are a very attractive option. For the 40 meters band Dxers a vertical just 7 meters high, that is around 23 feet is a quite useful option….
For all of you radio amateur operators that are thinking forward to the extended period of very low solar activity, the second option is to use a magnetic loop antenna of as large a diameter as possible and equipped with remote control tuning…
Large magnetic loops using copper pipes that may be as thick as 50 or 75 millimeters, that’s two to three inches , have proven to be very effective for long distance communications, although they do require constant retuning when changing the operating frequency by just a few kiloHertz. In other words they are very restricted operating bandwith antennas… making them not very attractive for amateur contests participants that need to change frequencies very fast in order to increase the number of stations logged.
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