Monday, August 25, 2008

DXers Unlimited - weekend edition August 23-24

Dxers Unlimited
By Arnie Coro CO2KK

Hi amigos radioaficionados ! You are most welcome to the weekend edition of Dxers Unlimited, coming to you from Havana, via short wave and also via the world wide web audio feed from in English from 05 to 07 UTC.

This Saturday was ideal to go to the beach and also to generate a good tropo duct opening !!!

Now here is item one: One of the most popular ways of enjoying the radio hobby is, without any doubts,AM medium wave broadcast band Dxing, that according to the e-mail messages, postcards and letters received here, generates a lot of interest among listeners of Dxers Unlimited around the world.

Receivers and antennas especially designed for AM medium wave broadcast band Dxing will make a big difference on the results that you can achieve, while locations with very low noise levels and far away from high power stations are described by the avid AM Band Dxers as the ideal places where to go for a Dxexpedition.

With solar activity at an all time low for the past 11 years, we may be able to enjoy a very nice upcoming autumn equinox AM broadcast band DX season...

More about the extremely low solar activity that has prevailed since October of last year...

The month of October of 2007 registered an extremely low monthly sunspot average of 0,9, that was followed by a very slightly higher figure of 1.7 in November, then during December of last year activity increased to 10.1, only to take a dip to 3.8 during January, continue the downward turn in February to 2.1, and then March data shows a montly sunspot average of 9.3.

Some scientists thought that solar cycle 24 was starting , but they were wrong... April and May of 2008 average monthly sunspot count registered the same figure of 2.9, June was just slightly more active at 3.1 and then July brought the lowest monthly sunspot average of the whole cycle,just 0.5, that meaning that for practically 31 consecutive days solar optical observers saw a totally blank solar disc....

And to bring to an end this lenghty but very important statistical analysis, so far, during 22 days of the month of August, only a very small cycle 23 sunspot was seen . In total agreement with the zero sunspot count that has prevailed during August, the microwave solar flux at 10.7 centimeters way length has stayed at rock bottom levels , with an average very near the minimum ever registered of 64 units.

Now, after you have patiently heard those terribly low numbers, here is the analysis of what they may mean for the low frequencies DX enthusiasts, a crowd that includes operators of automatic low frequency beacons, listeners to the natural radio emissions of Planet Earth that include the often heard but not very well known whistlers, Long Wave AM broadcast band Dxers, the radio amateurs that are operating on the two thousand and two hundred meters band, non directional aviation beacon Dx
hunters , the new group of radio amateurs that are operating on a segment of the old Marine 500 kiloHertz band, and those that are not yet allowed to transmit on the 600 meters band, but that as I am doing are constantly monitoring that new ham band in order to learn more about its unique daytime propagation characteristics.

But if you add the people devoted to the above mentioned ways of enjoying the radio hobby, they are no match to the hundreds of thousands of persons around the world that in one way or the other have a good time trying to pick up DX stations on the AM medium wave broadcast band, where practically every nation in the world has at least one station operating.

If the present extended period of very low solar activity continues during the months of September and October then AM medium wave broadcast band Dxers will enjoy a super DX season, because of the very low ionospheric absorption that will prevail during the upcoming autumn equinoctial period, that should be starting in about two weeks and extend at least until mid October.

Si amigos, yes my friends, oui mes amis, AM broadcast band Dxing , according to my propagation forecast, is going to be really amazing, and the only thing that could spoil this autumn equinox DX season will be a sudden , abrupt and so far unexpected increase in solar activity.

Get ready for what is going to be possibly the best AM band and Long Wave broadcast bands DX season in years to come... and stay tuned to this program , because our technical topics section for today will provide you with several nice tips for low frequency Dxing, in the range from 10 kiloHertz all the way up to 2 megaHertz, because, yes... the 160 meters amateur band is also going to be excellent for Dxing during the upcoming autumn equinox...

You are listening to Radio Havana Cuba, the name of the show Dxers Unlimited, and here is now our technical topics section, that is competing in popularity with our HF and low band VHF propagation updates and forecasts and even with ¨¨ La numero uno¨¨ the most requested and popular section of this program ¨¨ ASK ARNIE¨¨

So get ready to copy, here are several really practical and easy to follow tips for Dxing the low frequency spectrum from 10 kiloHertz all the way up to the end of the AM broadcast band, and even to the top of the amateur 160 meter band amigos !!!

Tip number one: Check your noise level, and try to find which are the radiofrequency noise generators that sorround your listening post. I remember many years ago when I first visited a point to point short wave communications system receiving station, that all the lamps they used were incandescent lamp bulbs... when I asked the Chief Engineer at the Prensa Latina news agency HF receiving station out in the ountryside near Cuatro Caminos a small village southeast of Havana , he told me that fluorescent lamps were prohibited at the receiving site, because they generate a lot of Radio Frequency wide band noise.

He also added that the power line that provided electricity for the receiving site came by means of an underground three phase high voltage cable that was more than two kilometers long, so that no overhead power lines were within the vecinity of the antennas.

Of course that I am aware that the average low frequency Dxer cannot enjoy the benefits of such a specially built site, but you can certainly check carefully and find out, for example, how each of your home´s electrical distribution systems contributes to your low frequency bands noise level. Just by going to the circuit breakers at the entrance and disconnecting them one at a time, you may be able to find, for example that the breaker providing power to the living room , when disconnected, makes low frequency reception much better.... Something that later was
traced to a fish water tank air pump... because the nice tropical fish aquarium was located right in the living room of the house. This was a real life experience for a Dxers Unlimited listener that sent a question to the ASK ARNIE section of the program asking how he could find out the source of a ticking sound that was making his reception on the low frequency bands very difficult , and even up to 10 megaHertz very annoying, because of a repetitive tick , that in this particular case
was caused by the fish tank air pump !!!

By switching the circuit breakers one at a time, you may also find out that the older computer in the kids room , the one still running with a big CRT picture tube monitor is a terrible noise generator... a problem that can be solved by changing to an LCD monitor, but be aware , that it MUST be an LCD monitor,because the PLASMA displays are even worse noise generators than the old picture tubes used by the early computer monitors.

Next tip: This will require a small AM broadcast band receiver and a pair of good quality headphones...The next step is to go all around your home with all the lights ON, and put the small portable radio near each lamp, while it is tuned to an empty frequency at the low end of the AM broadcast band. As many Dxers Unlimited listeners have learned in the past, because this is not the first time that I explain this procedure in the program, well, this easy technique will quickly point at the
noisy lamps...

With the compact fluorescent light bulbs now in use all around the world to save energy and reduce CO2 pollution , this is particularly important, and let me add amigos, that ¨¨ Not all compact fluorescent light bulbs are created equal¨¨ If you realize what I mean... The fact is that all radio hobby enthusiasts must learn which are the CFL´s compact fluorescent lamps that make less radio frequency noise, and to your advantage , there is the coincidence that the ones that generate less noise are usually the highest quality CFL´s , although I must add that they are also usually the most expensive too..

The next tip is also related to the way your home is illuminated, and it may be considered by some really dyed in the wool low frequency Dxers an essential step if you really want to reduce the local noise level... Try to start installing Light Emitting Diode Lamps... but be very careful, because some commercially built LED lamps are terrible noise generators too...

The reason that some of those super energy saver LED lamps generate noise, is that they used a switching mode power supply that sends down the drain any advantage that the low voltage light emitting diodes offer in contrast to the compact fluorescent lamps.

So, before buying LED light bulbs that can be plugged directly to replace the
incandescent or CFL bulbs, check that they are not using a switched mode power supply...

Some radio amateurs that have acquired all along their ham radio careers the ability to homebrew equipment, have built very nice arrays of white light emitting diodes that are powered from linear power supplies and so provide excellent illumination, no flicker , and no noise...

Just recently, a friend that visited here gave me several white light emitting diodes, and I decided to use them for making a lamp that is now located at my listening post and amateur radio station operating position, with excellent results... Although the Compact 15 watt fluorescent lamp that I used there was not very noisy, my sensitive broadcast band DX receiver could pick up the background noise that could only be suppressed by switching OFF the CFL lamp.

With the new white LED array of six diodes, the noise level is ZERO !!!

Well amigos, the topic of low frequency Dxing is so fascinating that it seems like it would require more time alloted to it during upcoming Dxers Unlimited programs.. You may want to provide me with feedback about today´s tips for reducing the RF noise level at your home , and also tell me if you have any question related to finding noise sources and trying to wipe them out !!!

Si amigos, yes my friends, zero sunspots one day after the other, an amazingly low monthly sunspot count for July, and August is moving along the same line, but despite the minimum solar activity, radio amateurs continue to enjoy the hobby by traveling to remote DX cations and usually combining nice vacations with giving to fellow hams the opportunity to work new and usually rare prefixes...

Stay here until the end of the program because as ALWAYS when I am in Havana, at the end of the show, have your tape recorder ready for Arnie Coro's Dxers Unlimited's HF plus 6 meters propagation update and forecast , a practical guide for optimizing the enjoyment of your radio hobby , be it short wave listening or amateur radio, or any other of the more than 83 ways we can enjoy radio !!!

Here are is now one of the most recent Dx expeditions soon to be on the

The Principality of Monaco, with the ITU Prefix 3A will be on the air thanks to Patrice, a french amateur that will operate his Dxpedition with the callsign 3A stroke F5RBB starting on the first of September and for 10 days. Patrice will be on the air on 40, 20, 15 and 10 meters and his QSL information is via his home call via direct or trough the French QSL bureau.

He will provide a nice opportunity for newcomers to the hobby to work Monaco for the first time.

And now as always at the end of the program here is our HF and low band VHF propagation update and forecast. Solar activity expected to continue at baseline levels with solar flux not higher than 70, expect noise levels on the low frequencies up to 10 megaHertz to continue high during the late afternoon and early evening local time ,due to summer weekend edition thunderstorm activity.

Best time for long haul DX continues to be starting at around 2 hours before sunrise and just a brief period after sunrise. See you all at the mid week edition of the program amigos, and don´t forget to send your signal reports and comments to inforhc at enet dot cu or Via Air mail to Arnie Coro, Radio Havana Cuba, Havana . Cuba