Re: [HCDX] Dxers Unlimited's mid week edition for 24-25 July 2007 ( short form edition to provide time for Pan American Games special coverage by RHC)

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

Radio Havana Cuba
Dxers Unlimited's mid week edition
radio amateur CO2KK


Hi amigos radioaficionados... here is again a short form edition of your 
favorite radio hobby program, coming to you from Havana. We continue to 
make a little more air time available to our sports coverage of the Pan 
American Games taking place in Rio de Janeiro, Brazil.

I am Arnie Coro, radio amateur CO2KK, and here is item one for today. 
It's a news item... Cuba has a new satellite TV channel, it was named 
Canal ACN, and the ACN stands for Cuban News Agency in Spanish. The new 
satellite channel is on Hispasat Id Transponder 79 vertical 
polarization, and the footprint of the bird provides practically total 
coverage of the Americas with just a small area in the Amazonian region 
of Brazil that is not covered by the satellite signals.

The signal of Canal ACN at this moment is a television text only type of 
signal, that is created here in Havana using digital technology and then 
uplinked to the satellite for broadcasting.

In the near future the now text mode signal with accompanying audio 
background will include graphics too. The main objetive of Canal ACN is 
to provide Cuba medical doctors and other Cubans providing aid to Latin 
American and Caribbean nations with up to date , actually up to the 
minute information and news about Cuba.

The same Hispasat ID transponder also is at this moment broadcasting 
other Cuban live television channels as well as several radio stations, 
including Radio Havana Cuba spanish language programs , and soon we will 
also include English and other languages too.

Item two: Learn more about the HF propagation to expect during the this 
upcoming week at the end of the program... Here is an advance notice: 
solar activity continues at extremely low levels amigos !.

Now, here is a short break for station ID. I am Arnie Coro, radio 
amateur CO2KK and my e-mail is arnie@xxxxxxxxx

......

Si amigos, you are listening to Radio Havana Cuba, the name of the show 
is Dxers Unlimited, and here is item three of today's program... It's 
our antenna topics section, answering a question sent in by a listener 
that seems to be very enthusiastic with the expected good propagation 
conditions on the 160 and 80 meters amateur bands during the bottom of 
the solar cycle. Amigo Glenn from the state of Washington wants to know 
what could be gained by installing a half wave or even a 5/8 wavelength 
vertical for 160 meters, even though he did his numbers and knows that 
these are both very tall antennas, that will require a lot of space and 
also of top notch mechanical engineering. And Glenn adds that he wants 
to know if the very high antennas can be also used on 80 meters.

Well amigo Glenn, first of all here is your amigo Arnie Coro's advice 
regarding the installation of tall towers... If you do have the 
resources, both financial and of real state to install such an antenna 
system, by all means put the project in the hands of professional 
antenna designers and installers... There are no room for mistakes when 
you are installing a 300 feet or almost 100 meters high tower, and the 
tuning up of such a system requires using professional instruments and a 
lot of know how.

Also such a tall steel structure will require placing aircraft
beacons and obstruction lights to comply with worldwide aviation safety 
regulations...

By no means I want to discourage you, but it is my duty to provide this 
initial and very important advise for anyone wanting to design and 
install really high radio antennas...

As a bonus, if you finally are able to complete the project, the same 
tower, if fed as a vertical grounded folded monopole, will provide an 
excellent support structure for HF, VHF, UHF and microwave antennas...

Years ago, I exchanged correspondence with an amateur radio operator in 
Brazil that is a 160 meter band enthusiast, and he was able to install a 
very tall vertical antenna placed in the center of a small lake, with 
outstanding results .

Yes, again, any attempts to install very high metal structures should be 
handled with great care and with the aid of professionals, without 
forgetting the proper handling of the legal framework with the local 
authorities and even the requirement to provide insurance against 
damages that may result from the collapse of the tower...

Last but not least, if you are not properly trained, never work atop a 
tower , and even if you have training, never do it alone, because you 
don't need to be added to the very sorry statistics of amateur radio 
operators that have been killed while working on their antenna systems...
.....

.
NEXT TOPIC:: DRM noise continues to create lots of problems to adjacent 
channels operating with standard AM double side band plus carrier 
signals... In my opinion there is no doubt that the wide DRM 
transmissions have to do with poorly adjusted final amplifier stages of 
the transmitters, because DRM requires extremely linear amplification in 
and a very difficult to meet peak to average power ratio handling 
capacity of the transmitter driver and final amplifier stages...

Let's hope that soon the DRM consortium will take corrective action 
regarding these problems as they are shedding a very dark image to DRM 
broadcasts, that again in my opinion , when properly done with adequate 
equipment should be more compatible with other users of the radio spectrum.

More about homebrewing radios, and the joy of operating them... 
especially after you are able to clean up all the initial bugs that any 
homebrew project usually has... A unique regenerative radio design that 
I tested here is capable of operating while using extremely low voltages 
applied to the vacuum tubes...

The regenerative detector stage is able to provide excellent reception 
while running just two, yes, two volts on the plate or anode electrode, 
and the audio amplifier stages run from a 9 volts battery.

As a friend that has seen this radio said, it's a vacuum tube radio with 
a transistor set power supply...

A further experiment with more common and easier to find vacuum tubes 
has proven that an excellent radio performance can be achieved while 
just running 12 volts DC, a voltage that is easily available from a 
standard accumulator or power supply.

Si amigos, electronics continues to surprise me every day, like in this 
other example, when I was testing Saturday morning an amateur radio two 
meters band handie talkie with a dummy load resistor .... and suddenly I 
heard someone coming back to my hello test... via the local repeater on 
145.190 ...

So, it was evident that the dummy load was radiating enough signal to
trigger the very sensitive receiver of the repeater that is located 
about three miles from my home QTH, atop the Habana Libre Hotel, a 35 
stories high building in the Vedado district.

When discussing this unsual two way QSO using my 50 ohms
terminating resistor dummy load as an antenna, with a friend, he 
recalled a similar contact on 10 meters with the dummy load as an 
antenna, but not with a local station... He said he has the QSL card to 
prove that he worked a station in North Carolina on 10 meters single 
side band, while his 100 Watts PEP transceiver was connected to a dummy 
load, that it was evidently not very well shielded at all...

And now amigos, as always at the end of the program, here is Arnie 
Coro's Dxers Unlimited's exclusive and not copyrighted HF propagation 
update and forecast ....solar flux is not even reaching 70 units, and 
the geomagnetic field is very quiet, although the forecast calls for an 
upsurge in geomagnetic activity by next Friday, due to an expected high 
speed solar wind coming from a coronal hole. Propagation on the HF bands 
continues to be very poor during local daylight hours, and just a bit 
better after local sunset... Send your signal reports and comments to 
arnie@xxxxxx and VIA AIR MAIL to Arnie Coro, Radio Havana Cuba, Havana, 
Cuba.

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