Dxers Unlimited mid week edition for 11-12 January 2005
radio amateur CO2KK and host of this Radio Havana Cuba show
Hi amigos radioaficionados ! Welcome once again to your favorite radio hobby
program, coming to you on RHC shortwave frequencies and also via our webcast
from www.radiohc.cu... I am Arnie Coro in Havana, and this is the mid week
edition of the show... Here is now item one:Solar activity is oscillating from
very low to low, and the effective sunspot number was 35 at mid morning local
time Tuesday here in Cuba. Three small active sunspot groups in sight on the
solar disk at this moment and only one looks like capable of producing flare
activity during the next few days...
Item two: YES, there are even more than 77 ways that you and I may enjoy this
wonderful hobby, but so far my count is at 77... and it may go up after I review
a suggestion by a Canadian listener that human powered radios are also another
attractive aspect of the hobby... According to amigo Walt from Nova Scotia, he
enjoys both receiving and transmitting using radios that are powered by himself.
The receiver he is using has an adapted Bayliss clockwork generator from another
radio, and the transmitter is powered by pedalling a stationary bicycle !!! More
about human powered radio later in today's edition of Dxers Unlimited. Item
three: The LAMPKIN oscillator circuit is much more stable than a classic Hartley
and wiring an already existing Hartley oscillator to use the LAMPKIN circuit can
be done in just a few minutes in most cases. The LAMPKIN oscillator
uses taps located at two different points of the oscillator coil, in order to
reduce grid or gate loading to increase the frequency stability of the variable
frequency oscillator... More about homebrew VFO's and how you can make them
really very stable as Dxers Unlimited continues in just a few seconds... Jose
Costa Pupo is my sound engineer and producer, I am Arnie Coro in Havana, back in
a moment !!!
......
Si amigos, sure my friends, when you listen to Dxers Unlimited you certainly
share a unique experience, as you learn about our wonderful hobby in an easy to
understand way, and whenever you wish, if you have any doubts, any technical
questions, just e-mail me to arnie@rhc.cu, again arnie@rhc.cu and your question
or questions will be answered on the air and also the reply will be sent back to
your e-mail account, this by the way is a unique Dxers Unlimited service to the
world's radio enthusiasts...
Human powered radios....using radios that obtain their electricity from a person
winding a clockwork , hand cranking a generator or pedalling a stationary
bicycle connected to a generator has made number 78, si amigos, Walt , the
Canadian listener from Nova Scotia has convinced me that human powered radios
open up yet another way of enjoying our hobby in a unique way... Now those who
criticize us radio hobbysts as potato couch guys, will be surprised to learn
that we can share two wonderful hobbies at the same time... exercising with a
stationary bike and generating our own electricity to power the radios.
After receiving Walt's e-mail, I attempted to couple a small generator to a
bicycle that I had kept in the garage for several years, and all I can say is
that IT WORKS !!! The small direct current generator that was originally
intended to power the headlight and a small taillight for the bicycle, provided
enough power to make a small transistor radio work quite well, after I added a
big ten thousand microfarad capacitor in parallel with the generator output.
Please note that this generator was not charging a battery, but feeding directly
the radio with its direct current output that was very near 6 volts when I
pedalling at slightly below my long range biking cruising speed...Later I
connected a 6 volts 7 ampere hour accumulator that was almost totally discharged,
according to my measurements, and started to charge it with the generator
coupled to the bike's tail wheel...
About 45 minutes later, I tested the battery electrolyte density and to my
satisfaction found out that the accumulator had charged up !
I am now looking for a more powerful 12 volts DC generator to set up a human
powered amateur radio station myself !!!
Si amigos, yes my friends !!! You can enjoy the radio hobby now in 78 different
ways, after including human powered radios in the list !!!
......
Radio Havana Cuba is now on its 44th year on the air, yes amigos we went on the
air on the 24th of February of 1961, using the name Onda Corta Experimental
Cubana..and on May Day of that same year the name Radio Habana Cuba was heard
for the first time on the short wave bands...Now after this bit of history,
let's go to our technical topics section.... the LAMPKIN oscillator is a
variable frequency oscillator circuit that has proven to be more stable than the
classic Hartley cathode tap oscillator. The LAMPKIN, named like all other
oscillators after its inventor, uses two taps on the oscillator coil instead of
one. It keeps the cathode tap slightly above the ground terminal of the coil to
develop the necessary feedback to oscillate, and then it uses another tap to
connect the grid or gate circuit terminal.
That means, in other words that the grid or gate electrode of the active device
is connected at a tap below the extreme hot end of the coil, something that
LAMPKIN proved improves the stability of the oscillator circuit considerably.
Converting a Hartley VFO to a LAMPKIN, is very easy to do, one just needs to
unsolder the grid or gate connection from the top of the coil and connect it a
few turns down , typically about 20 percent down the coil will work fine.
A LAMPKIN oscillator working with the grid circuit tuned to 80 meters and
doubling on the plate circuit to 40 meters provides excellent stability , so
that you can homebrew a classic MOPA, or Master Oscillator Power Amplifier
transmitter using just two vacuum tubes as active devices...Using a large
diameter ceramic coil form wound with large diameter wire for the oscillator
coil will also improve frequency stability of this ultra simple circuit
configuration that has proven to be quite easy to build and adjust.
.....
Dxers Unlimited's mailbox is located at arnie@rhc.cu, again arnie@rhc.cu, so
take a little time at the end of the program and give me your impressions and
opinions about the program and how do you think it can be improved !!! Send mail
to arnie@rhc.cu, or VIA AIR MAIL to Arnie Coro, Radio Havana Cuba , Havana ,
Cuba
And now as requested by many Dxers Unlimited listeners, here are some nice DX
tips , especially selected for radio amateurs ... Japan, get ready for some rare
islands that are valid for the Islands on the Air IOTA AWARD
ARGENTINEAN RADIO AMATEURS WILL BE AT MARTIN GARCIA ISLAND !!!AND ALSO FOR THOSE
THAT COLLECT LIGHTHOUSE STATIONS ... THEY WILL BE AT THE LIGHTHOUSE TOO !!!
LU - A group of operators from Radio Club Argentino (LU4AA) will be active with
two stations on 10-80 metres from Martin Garcia Island (SA-055) and Lighthouse
(ARG-045). Look for LR4D (CW) and LR5D (SSB) from around 21 UTC on 13 January to
around 15 UTC on the 16th. QSL via LU4AA, direct or bureau.
LU - LU9DA, LU5EW, LU1DWW and others plan to operate (on 10, 15 and 20 metres
SSB) as LU2DT from the lighthouse at Punta Mogotes in mid January. QSL via LU2DT
(RC Mar del Plata, P.O. Box 664, B7600 Mar del Plata, Argentina).
P2 - Jerry, P29ZAD will be active from Tabar Island (OC-099) on 18-27 January.
He will operate during his spare time, probably around 21 and 8 UTC on ± 14260
kHz. QSL direct to Jerry Walker, P.O. Box 264, Ukarumpa, EHP 444, Papua New
Guinea. [TNX The Daily DX]
ST - Dane, S57CQ/ST2T is still in Sudan and he is likely to be working there for
the next three months. He plans to operate RTTY soon. QSL via S57DX, direct or
bureau. [TNX S57DX]
UA - Mike, UA0MF reports he will operate as UA0MF/9 from Ural area (RDA CB-54,
GL MO04ew), near the border with European Russia, on 10-20 January. He will pay
special attention to the low bands.
VE - VE3JM and VE3EY will operate as VE2/homecall from Sept Iles, Quebec (Zone
2) on 13-19 January. Their main focus will be on the low bands. QSL via home
calls. [TNX NG3K]
VK0_mi - Dave, VK0MT is currently active from Macquarie Island (AN-005). Owing
to his work commitments, he has time for amateur radio only during his evening
hours. He operated for a few days from a small hut at Water Fall Bay, using a
long wire and a vertical whip antenna, but once back to the main research
station, he should have access to better
............
And now amigos ,as always at the end of the program here is Arnie Coro's Dxers
Unlimited's exclusive and not copyrighted, in the public domain HF plus low band
VHF propagation update and forecast... Solar flux hovering around 90 units and
it seems to be moving up slowly now...
The effective sunspot number , that's the input that you are asked by many
propagation forecasting software programs, is at around 35, and that means that
the bands above 20 megaHertz will open up for very short periods and only to the
best possible paths...
Expect 10 and 12 meters to sound like yet another VHF band most of the time,
expect for brief openings...
Look for yet another upcoming solar wind stream that is coming from a coronal
hole ... As the high speed protons hit the magnetosphere by Wednesday, as
expected, yet another high latitude geomagnetic storm may develop, making
propagation conditions take a turn for the worse...!!!
