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Thursday, June 9, 2011
Wednesday, June 8, 2011
Beautiful Shuttle-ISS Shot
For a better (high res) view and more details, go here:
http://news.discovery.com/space/big-pic-shuttle-endeavour-docked-space-station-110607.html
The digipeater on the ISS has been picking up my little 2 meter APRS sigs and sending them back down.
Tuesday, June 7, 2011
Searching for the Sputnik Schematic
Greetings Space Historians!
We are a group of radio amateurs and we probably rival you in our
technical geeky-ness. We are now involved in an effort to re-create
and put on the airwaves replicas of the 20 MHz transmitters used in
Sputnik 1. (We will use the amateur radio 21 MHz band).
We are trying to find a schematic diagram for the transmitter. Can
you help us? Thanks.
------------------------
Gentlemen,
Arnie, CO2KK, told me last night that as a 15 year-old boy he'd made
it into the newspaper by picking up Sputnik's signal on his Hammarland
Super-Pro receiver.
Don Mitchell - a physicist now retired from the Bell Labs - also wrote
last evening to ask if I knew of a schematic diagram for the two
transmitters used on Sputnik-1. Mr. Mitchell maintains an informative
web site on the topic of Sputnik. Here, for example, is the link to
his page on the first of the series of "Travellers" to be lofted into
orbit in late 1957 into 1958.
http://www.mentallandscape.com/S_Sputnik1.htm
To the best of my knowledge the schematic for what may be the most
famous QRPp transmitter has never been published. It's a shame,
particularly as it would have been great fun to build an approximate
replica for use on the ham bands
However, I woke up this morning wondering why should we allow the lack
of an original schematic to stop us when there's plenty of descriptive
evidence available? "Spaceflight Magazine," for example, published a
wonderful article on the 50th anniversary of Sputnik. The story was
pieced together from original documents over a period of 20 years. You
may read the article here
http://faculty.fordham.edu/siddiqi/writings/siddiqi_sputnik_history_2007.pdf
"The two D-200 type radio transmitters operated on frequencies of
20.005 and 40.003 megacycles at wavelengths of 15 and 7.5 m. These
transmitters (which obviously used vacuum tubes) each had a power
intake of 1 watt and provided the famous “beep-beep-beep” sound to
Sputnik. The signals on both the frequencies were spurts lasting 0.2
to 0.6 seconds, and carried information on the pressure and
temperature inside the satellite; one set would transmit during the
“pauses” of the other."
"Despite objections from just about everyone, Gringauz insisted that
PS-1 carry a high frequency transmitter (the 20.005 MHz transmitter
operating in the decameter waveband) in addition to the VHF
transmitter (which had been commonly used on Soviet ballistic
missiles). ...In the end, Gringauz won over his opponents, partly
because everyone agreed that a high frequency
transmitter would ensure that the radio transmissions would be heard
around the world. The transmitter hardware was built by one
of Gringauz’ youngest engineers, Vyacheslav Lappo..."
>From other sources we know the transmitter used vacuum tubes rather
than transistors. This site mentions that when the received signal
level was quite strong, the presence of a back-wave while the other
transmitter was keyed could be noted.
http://www.amsat.org/amsat/features/sounds/firstsat.html
The RF oscillator, at a minimum, must have been free-running. So,
we're talking a vacuum tube crystal-controlled oscillator and a PA
having an input power of 1 watt. They may have used a PA driver stage,
or perhaps a frequency multiplier stage. If they did use a multiplier
then it must have been allowed to free-run as well. But given the
battery drain considerations, I would have done my best to reduce the
number of vacuum tube heaters, or filaments to a minimum. As such, I
think there's a fairly good chance this was a simple, MOPA design
(oscillator-> PA).
I found what might be a photograph of the transmitter on page 26 of
the December 1957 issue of the Soviet "Radio Magazine." Perhaps our
Russian speaking group members can confirm this and provide us with
other clues appearing in the article text? The magazine can be
downloaded at
http://publ.lib.ru/ARCHIVES/R/''Radio''/
Click-on ''Radio'',1957,N12.[djv].zip. The "zipped" December issue
appears in DJVU format. Don't miss the nice Sputnik cover art.
This re-post talks about the center-fed Vee dipole used (the 15m
transmitter used the 5.8meter dipole) among other things.
http://hamradio.mybb.ru/viewtopic.php?id=625
Getting to get the point, this morning I woke up thinking about how
plentiful vintage Russian military tubes are these days. Remember how
inexpensive US military surplus used to be? That's how it is right now
with Russian components (and the characteristics of some of these
tubes are simply amazing). All I can say is get 'em while they're hot,
as it surely won't last forever.
It also came to me that Expanded Spectrum Systems sells an HC49
crystal cut for 21060kHz for two and a half-bucks each.
Finally, I remarked to myself that propagation-wise, 15m may well be
open for business come the 54th anniversary of the launch of Sputnik-1
next October the 4th.
You've probably guessed by now what I'm going to propose. We have
plenty of time to throw together a simple 15m CW vacuum-tube
transmitter having an input power of 1w or less. We could use any
tubes that we like but I'm going to build mine using 1950's vintage
ex-Soviet devices. I plan to power mine with one or two of those
ubiquitous 12V sealed-lead-acid batteries. I'll VXO my crystal and
I'll let it free-run during transmit; both for historical reasons and
to improve the signal quality.
Perhaps some of the antenna gurus here would lend a hand by modeling
and testing something akin to the original 70 degree Vee dipole? Would
this be a practical antenna?
I propose that beginning on "Sputnik Day" we launch our 1 watt Sputnik
clones on 15m CW. Instead of calling CQ, our call could be along the
lines of "Beep_Beep_Beep_Beep_Beep_Beep de AA1TJ". In other words, six
letter E's followed by our call sign. Given that I can barely organize
the socks in my underwear drawer, perhaps someone skilled at
organizing events would take up the cause?
One more thing. Poking around on Google last night, I was struck by
how many people remarked that the experience of Sputnik had changed
their lives. Some decided to become engineers, scientists or amateur
radio operators. I didn't know it at the time, but Sputnik changed the
way that I was educated. Not only did this little QRPp transmitter
make a tremendous impact on the world, but radio amateurs were front
and center. It seems appropriate that we should commemorate this
extraordinary day in the history of QRPp.
http://www.youtube.com/watch?v=CHaJDuq6tBM
(they were seeing the orbiting booster stage rather than the satellite)
Sputnik Mania...the complete film in two parts (warning...contains
some political "button-pushing")Greetings Space Historians!
We are a group of radio amateurs and we probably rival you in our
technical geeky-ness. We are now involved in an effort to re-create
and put on the airwaves replicas of the 20 MHz transmitters used in
Sputnik 1. (We will use the amateur radio 21 MHz band).
We are trying to find a schematic diagram for the transmitter. Can
you help us? Thanks.
http://www.youtube.com/watch?v=8jI5RBRWIOE
If I happen to learn more about the original transmitter I'll be sure
and post it on my blog or web site. I found particularly interesting
the fact that WWV interrupted some of their 20MHz transmissions in
order to accommodate Sputnik's signal; a gentlemanly thing to do
As for the possibility of an event along these line, any comments or
discussion is most welcome. I plan to make a start on my little
Sputnik sender upon my return from vacation in July.
Greetings Space Historians!
We are a group of radio amateurs and we probably rival you in our
technical geeky-ness. We are now involved in an effort to re-create
and put on the airwaves replicas of the 20 MHz transmitters used in
Sputnik 1. (We will use the amateur radio 21 MHz band).
We are trying to find a schematic diagram for the transmitter. Can
you help us? Thanks.
Ha...I just received several fairly good-quality color photos of the
original Sputnik transmitters! At first glance it looks as though they
used two subminiature pencil tubes! The quartz crystal looks very
similar to our HC-18/u package. The RF portion is very simple in
appearance. In fact, it reminds me of something you'd find in a 1950's
ARRL Mobile Radio Manual! ;o)
The fellow who sent these apparently has a contact with one of the
original Sputnik (non-electronic) hardware designers; who is said to
be "still very much alive." My contact is going to make an inquiry
with his Russian contact about the transmitter.
Very cool...
73/72,
Mike, AA1TJ
Monday, June 6, 2011
Radio Telescope Ausie Eye Candy
Sunday, June 5, 2011
Homebrew VHF Phone from Down Under
----
Hi Bill,
I know you like DSB transceivers, so I'm sending you a link to my 144Mhz
DSB transceiver which I've just completed.
Thought I would try and see if I could get the same circuits I use on HF
to work on VHF, turns out they do with a few minor tweaks.
Anyway here it is: http://members.ozemail.com.au/~jgprice/2M-DSB.html
Keep up the good work, love listening to your show.
Cheers
John Price
VK3AJG
Friday, June 3, 2011
Copenhagen Rocket Launched!
From New Scientist:
Original post from 1618 GMT:
A rocket built by a group of Danish space enthusiasts has successfully launched on a short flight high above its sea-based launch platform.
The non-profit organisation Copenhagen Suborbitals built the rocket for around £42,000. They hope to eventually fly a human on a suborbital flight to space using a beefed-up version of the rocket, which is just big enough for one person.
Their first launch attempt a year ago failed to achieve lift-off due to a malfunctioning hairdryer used as a heater inside the rocket.
But their second try on Friday was a success. A video of the flight can be viewed here.
In the video, the rocket can be seen lifting off from its launch pad on the Baltic Sea and soaring high into the sky amid cheers. "We're going supersonic!" someone is heard saying shortly after lift-off.
A few minutes later, the rocket is seen splashing down in the ocean.
Though the rocket itself seems to have performed well, the parachute meant to slow its return to Earth does not appear to have fully opened. "There has been mission anomalies – we are now analysing," someone says in the video.
It was not immediately clear how high the rocket flew. The goal was an altitude of about 15 kilometres.
But the launch team was clearly thrilled with the flight. "The joy is just so huge," Peter Madsen of Copenhagen Suborbitals told Denmark's TV 2, according to a Google translation.
"We've written a little piece of history," added Kristian von Bengtsen, also of Copenhagen Suborbitals.
Thursday, June 2, 2011
Amateur Manned Spaceflight?
Initially, I had my doubts about this one... Intriguing as it is, when I watched the video, I was struck by how similar their "just build it" approach is to my own. You know, build first, design later... Well, we have seen the results here, and I wouldn't want my life to depend on it! But who am I to judge? And the rockets they have produced are really impressive. Check it out. And there is an amateur radio homebrew connection.
Thanks Lars!
-------------------
I thought that you might be interested in following the guys at:
http://www.copenhagensuborbitals.com/
It is an amateur group with the mission of sending a human into space - I guess that there are quite a few knack victims among them ;-)
They are about to launch a test rocket in a few days, and they are quite serious about what they are doing!
Actuallly you have come across one of them, their electronics guy is OZ2CPU who has the picture of the opened SBL-1 DBM on his website http://webx.dk
Vy 72/73 de Lars OZ1CJX / OZ9G / 5Q5RP