Radio Havana Cuba
Dxers Unlimited
Dxers Unlimited's mid week edition for 7-8 November 2006
By Arnie Coro
radio amateur CO2KK
Hi amigos radioaficionados worldwide and orbiting the Earth... welcome
to the mid week edition of your favorite hobby program, I am Arnie Coro,
radio amateur CO2KK , and as always it is my pleasure to share with you
about seventeen minutes of on the air, and also on the world wide web
time... By the way our streaming audio is available from 05 to 07 UTC
>from the website www.radiohc.cu... Now here is item one: I gave the
finishing touches to the prototype SUPER J 2 meters band wire plus PVC
pipe antenna, and now it will go to the top of my tallest tower in
order to pass the real life test... Some people have been intoxicated
with computer modeling of antennas, and you all must be aware that there
is no substitute for actual on the air tests when a new antenna is going
to be evaluated. So in a few days, you will again be hearing about the
SUPER J wire plus PVC pipe low cost , easy to homebrew antenna.... Item
two...seems like a big sunspot is about to show up... it has already
produced some nice fireworks
seen by astronomers as eruptions coming out of the Sun's limb...
Item three : Super simple one diode plus one transistor REFLEX radio
circuit is working very nicely here now, after some experiments changing
bypass capacitors and the inductance of the radio frequency choke that
is essential for the REFLEX radio to work properly... A REFLEX receiver
is one that uses the same active amplifying device for both radio
frequency and audio frequency amplification... It was a circuit born in
the early days of radio, when vacuum tubes were very expensive , so
experimenters learned how to use them more efficiently...
By the way, the small graphic file of the ULTRA SIMPLE REFLEX RECEIVER
is available by sending an e-mail to arnie@rhc.cu
More radio hobby related information coming to you in a few seconds, as
Dxers Unlimited's mid week edition continues after
a short break
.........
Si amigos, yes my friends, this is Radio Havana Cuba, and in a few days
, after a lot of antenna work, we will be starting to use
our B-06 schedule, that will last until March of 2007... Among the
highlights for our English language program listeners are the
use of 6180 kiloHertz to replace our long time 9820 kiloHertz frequency
beaming to the center of North America...
Now item five: Electronic components are something a radio hobby
enthusiast must learn a lot about... Capacitors come in the most
different forms....and their losses are characterized by the Power
Factor.
For example metalized ceramic plate capacitors up to 390 pf have a
power factor of .001, so do resin-dipped ceramic capacitors up to 220
pf, also metalized polypropylene capacitors of 0.1 uF to 0.47 uF. But in
contrast the very popular for RF bypass use ceramic disc capacitors have
a Power factor of only 8% so , never used them to resonate loop antennas
!!!. Two
similar capacitors in series or parallel would have the same
power factor, so it does not matter how they are connected.
When building variable frequency oscillators, careful selection of the
capacitors used as part of the resonant circuit is essential, and it
will take quite some time to find the best combination that minimizes
frequency drift...
.
..........
Si amigos, back to our antenna topics section, that is turning up as one
of the most popular parts of this program... The popular J pole antenna
for the two meters FM band segment does require a form of suppressing
the so called common mode of radiation, that distorts its vertical
antenna pattern in a very significant way...The best way to stop common
mode currents
on the feed line when feeding a J-pole, is something always under
discussion... but the fact is that most people just put 5 or 6 loops in
the coax feed line as a "choke balun" ,something that seems to work
quite well in actual practice.
You can also use a ferrite Radio Frequency choke of the type used by
computer monitors consisting of two halves's of ferrite material that
clamp on to the cable... Both chokes are effective and easy to install,
but the coaxial cable choke balun is the winner as regards to its
cost.... it will certainly be much less expensive than the ferrite RF
suppressor !!!
And in amateur radio related news... watch for a rare call sign, a nice
new prefix to add to your log if you are a prefix hunter...according to
information received from Greece .
SX8F, that is Sierra X ray eight Fox is going to be operated by a team
Greek Hams according to information provided by SV1EEX - Nik -all the
operators are members of the Radio Amateur Association of Greece: and
they are SV1JG Cliff ,SV1EEX Nikiforos ,SV1GRM Theodor ,SW1GZL Lykoyrgos
,SV1HER Sotirios ,SV1HHC Dionisios ,SV1IZR Makis ,and what they have
planned is planned a dxpedition on the rocky islet of Falkonera (IOTA:
EU-113, with Lighthouse activation by the special call sign SX8F.
As far as it is known know, this is will be the first activation of the
rocky islet and the first activation of the Lighthouse too. Needless to
mention that there is not any inhabitant on the rocky islet.
SX8F will be on the air from during four days from the 15th to the
-19th of November 2006
Activity will be n HF from 160 to 6 meters plus VHF & UHF & SHF.and the
modes used are going to be SSB/CW/PSK/FSK441/SSTV/FM/RTTY with a very
special
interest in trying to work Africa on two meters via the Trans Equatorial
Propagation gateway...
................
ASK ARNIE, la numero uno, THE MOST POPULAR SECTION of Dxers Unlimited is
now on the air amigos...Today's question was sent by listener Nancy from
Oklahoma , USA... she wants to know more about meteor scatter
propagation, something she
said that she has noticed a number of times while trying to pick up
distant FM broadcast band stations.... Yes amiga Nancy, those stations
that suddenly come out of nowhere and are heard for periods from a few
seconds to one or may one and half minutes are signals that your radio
is picking up via meteor scatter propagation... They are best heard on
an empty FM band channel, but here in Havana, I have heard some meteor
scatter bursts atop semi-local stations... FM band DXers amiga Nancy
have developed some very special skills for monitoring the major
meteor showers and adding new stations to their logs... but every early
morning, just before sunrise, meteor scatter propagated FM broadcast
band and Low band analog TV channels 2 to 4 signals are easy to pick up
, even with a very modest external antenna system... A broadband log
periodic antenna capable of receiving from 50 megaHertz all the way up
to 150 megaHertz is an ideal one for picking up meteor scatter
propagation DX, but you must use it with an antenna rotor or rotate it
by hand , in order to be able to make best use of its directional
characteristics...
.....
And now amigos, as always at the end of the program, here is our
exclusive Arnie Coro's , not copyrighted, in the public domain HF plus
low band VHF propagation update and forecast
Solar flux and A index predictions
PREDICTIONS FOR 08 Nov 2006 10CM FLUX: 089 / AP: 013
PREDICTIONS FOR 09 Nov 2006 10CM FLUX: 093 / AP: 027
A new active solar region is about to appear at the East limb of the Sun
( this the return of active region NOAA917 or 918). It has shown a high
level of activity by producing a series of limb Coronal Mass Ejections
events over the last few days
and a C8.8 flare on Nov.6 at 17:43UT. This event generated nd a big CME
that was not Earth-directed. As the flare was
partly hidden by the limb, it was probably an M-class flare, i.e.
exceptionally strong for the current period. Although we have no
direct view of the region, a significant rise of the solar activity is
going to be over the next few days, with C flares and a 50% probability
of an M flare. The solar wind is currently weak and slow, with
corresponding quiet geomagnetic conditions. On November 8or early on
Nov.9, it is expected that a new fast solar wind stream originating in
the low latitude coronal hole now passing in the SW quadrant of the
solar disk will be arriving. This will produce active geomagnetic
conditions, with possible occasional geomagnetic storm intervals.
So it seems that amigo SOL is back in action, something that is going to
produce some interesting impact upon HF propagation conditions during
the next three to five days...So, be ready for
some nice surprises amigos ...
And don't forget to send me your signal reports and comments about the
program to arnie@rhc.cu, or VIA AIR MAIL to Arnie Coro, Radio Havana
Cuba, Havana, Cuba
