Tuesday, December 11, 2018

Dxers Unlimited, weekend edition 09 December

Radio Havana Cuba
By Arnie Coro CO2KK

Hola amigos radioaficionados now listening to the weekend edition of Dxers Unlimited, I am your host Arnaldo, Arnie, Coro, radio amateur CO2KK wishing you excellent reception of this the week end edition of this program .

QSL on the air to the many listeners that have sent signal reports and comments to inforh@enet.cu We do appreciate the recent reports that have also included mp3 audio files attached to the email messages... That is the most objective form of reporting the quality of reception amigos !

QSL on the air to Paul Brown from Canada who sent an mp3 file and a photo of the screen of his transceiver that show excellent reception of our 6000 kHz - 49 meters band frequency using our 010 degrees azimuth curtain antenna array.

Solar activity update....sixty percent of the days of this year 2018 went by without a single sunspot... A fact that continues to sustain the point of view shared by many heliophysicists that solar cycle 24 minimum is now reaching the lowest expected number of sunspots.

A reminder comes from Belgium... where the  Royal Observatory confirms the Provisional International monthly mean Sunspot Number for November 2018
: 5.9 (five point nine), again 5.9  ie the provisional international monthly mean Sunspot number for the month of November....

This very accurate data about solar activity confirms that cycle 24 is very near  its minimum and I may add that more small reverse polarity sunspots are expected from now on

Yes amigos , there are more than 91 well documented different ways of enjoying the radio hobby, and here I am to tell you about some of them today.

The two meters band FM mode Dxing is becoming popular in some parts of the world where the availability of multi mode transceivers is simply zero... But, FM mobile units and handie talkies are plentiful, something that makes possible to install better antennas and attempt to try to work far away stations that are not normally available using low gain omnidirectional antennas.

Here in Cuba the 2 meters band is the most used, due to the availability of transceivers used by the professional users within the frequency range between 140 and 160 MHz, that can be rather easily reprogrammed using a computer to radio interface and the proper software.

Some handie talkies are also good candidates for the software conversion making it possible to operate on the 144 to 148 MHz frequency range. When connected to a vertically polarized Yagi antenna of at least three elements, the operating range achieved extends well past the typical area that is normally  used for effective communications with  the FM narrowband voice mode. anUsing advanced complex Yagi antenna arrays of between 10 and 40 elements , FM 2 meter band

Dxers participate in many contests, and are able to link up via far away repeaters.....The main use of the 2 meters band here in Cuba is for local and semi-local contacts... with many radio clubs holding weekly round tables on previously announced frequencies, something that are very useful to keep club members informed about relevant activities and also provide excellent practice for emergency communications

Requests about the circuit diagrams and building instructions the ever popular Australian regenerative solid state radio keep coming... The name of that simple receiver is the MOORABIN--- Send your request for any of the circuits diagram in our collection to inforhc@enet.cu. Also receiving  requests and questions relate to or my Super Islander Mark Six  direct conversion short wave receiver keep coming in to my email inforhc@enet.cu - and as soon as they are received, it takes just a few seconds to send the electronic reply via the Internet.

By the way listeners that have built the different versions of this receiver, that forms part as a module of a more complex amateur bands transceiver tell me that the project was an easy going task that could be built using standard available parts

More tips about operating simple home brew receivers like the MOORABIN thee Super Islander Mark Six  Yes amigos, I do insist about the fact that using a battery power supply is essential for optimum performance  of any solid state receiver and there are no exceptions.

Here is now ASK ARNIE , the most popular section of this program with the reply to the question sent by listener Michael from Edimburg , Scotland.....he wants to know more about how to find the sources of radio frequency noise that are making his reception of the AM medium wave band simply impossible .

Well amigo Michael you are just one more of the millions of listeners that are having difficulties picking up stations operating within the frequency range of 530 to 1700 kHz, and that is assigned for the AM medium wave broadcast band... In the Americas stations use 10 kiloHertz channel spacing, while other parts of the world use 9 kHz for separation between stations.

With the advent of many different home electronics and electrical equipment using the switched mode power supplies, the situation regarding the baseline noise level between 100 kHz and 10 MHz  has increased significantly .

So my number one advice for you amigo Michael is to check for the presence of any electronic or electrical device that may be the source of harmful interference....because it may be using a switched mode power supply.
This can be done by exploring your house using a portable AM receiver tuned to the low frequency region, listening to an empty channel as you move around each room In actual practice you may also just disconnect the electricity circuit breakers one by one while listening to the AM sniffer radio.... You do not need to be a radio Sherlock Holmes to locate at least a few of the interference makers.... that are within the affected area, including computers, cellphone chargers, automatic furnaces controls, TV sets and even a fish tank pump...

Helping a local radio amateur to find what was making his 40 meters band full of very intense signal, we found that the ADSL modem was the culprit.
In an upcoming program, I will give advice on how to deal with today's most impacting problem affecting our radio hobby .... dealing with devices that generate radio frequency interference.

Send your signal reports, QSL requests and radio hobby related questions to inforhc@enet.cu or via airmail: Arnie Coro CO2KK, Radio Havana Cuba, Havana, Cuba