Radio Havana Cuba
Dxers Unlimited's middle of the week program for Tuesday
13 March 2018 By Arnie Coro radio amateur CO2KK
Hola amigos radioaficionados... hi my radio hobby friends
all around the world... YES, it is time, right for you to enjoy about ten
minutes of all radio hobby related information coming to you from Havana, Cuba.
I am your host, Arnaldo, Arnie , Coro and here is item one of today's
High frequency HF bands propagation will show a
slight improvement only if solar activity increases during the next several
days .... at this moment no new sunspot active region in sight , and the low
solar flux is hovering at rock bottom levels around 70 units and even less..
By the way let me tell you that the sudden upsurge in the
daily sunspot count and solar flux levels is something that may happen at
anytime during the bottom of the solar cycle ...
Yes, This is typical of
the tail end of a solar cycle, nothing abnormal at all... but it is certainly
quite disgusting, due to the long prevailing minimum solar activity to
tune around the short wave spectrum and hear nothing or just very weak signals
According to the most recent forecasts, next year, 2019 is going to be
worse with extended periods of much lower solar activity, that may
combine with solar events that will further disrupt propagation
Now, as we move into the spring equinox here in the Northern
Hemisphere and autumn equinox below the Equator,the beginning of summer, the
propagation conditions on the HF bands from 10 to 20 megaHertz will
improve as soon as more energy reaches the ionosphere from the Sun.
those of us that live North of the Equator, one of the most interesting effects
of late spring and summer propagation is a consequence of the daytime expansion
of the ionosphere... that causes an increase at night of the
maximum usable frequency for any given path after local sunset...
At times during solar minimum years, during the winter
season the maximum usable frequency at night may drop even below the six
megaHertz band amigos !!!
Now here is item two at the middle of the week edition of
Unlimited: I continue to enjoy very much the use of the
very original software application that runs on practically any computer
and makes possible to see the results of the REVERSE BEACON
NETWORK...this is certainly an amazing achievement accomplished by
volunteer amateur radio operators from many countries around the world.
would not attempt to describe here how the receiving stations that are
known as quote skimmers unquote, automatically pick up amateur CW Morse
radiotelegraphy signals that are calling CQ, and then also by means of an
automated subroutine measure the CW transmission speed and the signal to noise
If it sounds to you as science fiction, but it is certainly not, and
the now very reliable Reverse Beacon Network is adding yet another tool to
learn more about the extremely complex phenomena that make possible ionospheric
short wave propagation...
Yes amigos , I continue to run my QRP very low power
amateur radio station within the power range of one to five watts, with my
favorite setting at the three watts level. On Sunday's afternoons I spend some
of my leisure time operating on CW , on , twenty and my CQ calls at speeds
between 13 and 16 words per minute and see how my signals are picked up by
several skimmers and posted at the Reverse Beacon Network site so that they
could be seen by just typing CO2KK, the call sign of my amateur radio
Again, I want to repeat this valuable information for those of you
interested in knowing more about short wave propagation You may want to visit
the home page of the Reverse Beacon Network after calling CQ on CW if you
already are an amateur radio station operator, and just learn , for example,
what is happening when your friend Arnie Coro called CQ on the ham bands the
last time he was on the air.... Just type the following URL on your Internet
browser search line:
Then when the site opens and asks for whom you are
looking for, type co2kk and you will see the latest spots on each of the ham
bands where I called CQ...
Here is now ASK ARNIE, la numero uno, the most popular
section of the show... answering today a question sent by listeners from the
United States, Canada, Mexico, India, and South Africa, ... they all wanted to
know what is the most economical type of antenna that can be used to optimize
long distance amateur radio communications on the HF bands.......
That is a
really challenging question amigos... but I will try to provide you with
information about one of my favorite low cost DX capable antennas for the 20,
17, 15, 12 and 10 meter bands... It is not a multi-band antenna, it must be
made for the specific band you want to operate... Results achieved with it are
really good, if you are able to install the antenna in the clear...
It is made
using locally available and low cost materials... The one third of a wavelength
vertical antenna , using four quarter wave elevated radials produces a low take
off angle vertical radiation pattern, and is a perfect match for 50 ohms
coaxial cables feed line...
I used the 20 meters band version for many years,
and my signal was many times as good or even better as the signal delivered by
a local amateur operator that used a three elements multi band YAGI... Not to
say that he was very upset when we compared signals with a distant station...
He even made a surprise visit to my home because he thought I had installed a
three element YAGI ... I took my friend to the rooftop ands showed him the very
simple vertical and the elevated ground radials. Then we went down to the
station and measured the standing wave ratio , that indicated a 1 point one to
That is of course an almost perfect match !!! I had to
explain to him that there was no secret linear amplifier feeding the antenna,so
what was actually happening was that the 120 electrical degrees height of the
vertical monopole was concentrating the signal at low take off
Needless to say that two weeks later he had improved his station by
raising the Tribander YAGI to about 15 meters above his roof, and had also
installed a perfect copy of my 20 meters band one third of a wavelength high 20
meters antenna. Now more valuable radio hobby related information to keep in
mind when you decide to go on the air...
AGAIN, BE ASSURED THAT I AM A FULL TIME ADVOCATE OF QRP
or low power amateur radio operation although it is quite a challenge,
and that is why so many ham radio operators around the world are becoming more
and more involved in building or buying CW rigs that are within the power range
from 1 Watt all the way up to 5 Watt.... and some of us have installed
calibrated signal attenuators that can turn a one watt rig into a one hundred
milli watt transmitter at the flip of a switch that places a 50 ohms 10
decibels attenuator between the rig and the antenna , cutting the power
output to just one hundred milli watts...
The most popular CW operating frequencies for QRP or very
low power amateur stations are 7030 and 7040 on the 40 meters band, 10 dot 106
on the 30 meters band14060 on 20 meters, 21060 0n 15 meters and 28060 on the 10
Calling CQ on those frequencies will, in many instances,
bring back stations that regularly monitor them for QRP signals. You can always
go and check if any of the skimmers at the Reverse Beacon Network is picking up
your CQ call And by the way before I forget... QRP transmitters running no more
5 Watts into a half wave dipole fed with coaxial cable by
means of a one to one balun and installed at a good height will provide really
Send your signal reports and comments to inforhc at enet
dot cu or via Air Mail to Arnie Coro, Radio Havana Cuba, Havana Cuba
(Arnei Coro/R Havana Cuba)