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Showing posts with label Russia. Show all posts
Showing posts with label Russia. Show all posts

Saturday, April 9, 2011

Beacons from Space! Yuri Gagarin Anniversary


SB SPACE @ ARL $ARLS005
ARLS005 ARISSat-1 On the Air for Gagarin Anniversary

ZCZC AS05
QST de W1AW
Space Bulletin 005 ARLS005
From ARRL Headquarters
Newington, CT April 8, 2011
To all radio amateurs

SB SPACE ARL ARLS005
ARLS005 ARISSat-1 On the Air for Gagarin Anniversary

To celebrate the 50th anniversary of the first human spaceflight by
cosmonaut Yuri Gagarin, the ARISSat-1 satellite aboard the
International Space Station will be on the air using the station's
external antenna. Transmissions will begin on Monday, April 11, at
14:30 UTC and continue until 10:30 UTC on April 13.

To preserve the satellite's battery, transmissions will cycle on and
off. ARISSat-1 will transmit for 40 to 60 seconds, and then remain
silent for 2 minutes.

The FM transmissions on 145.950 MHz will alternate between a voice
ID, telemetry values, SSTV images and audio greetings in 15
different languages. One of the transmissions will contain audio of
a conversation between Gagarin and ground controllers that was
recorded during the historic flight.

A CW beacon will be heard on 145.919 MHz cycling between the
ARISSat-1 call sign, telemetry and call signs of individuals
involved in the ARISS program.

BPSK-1000 telemetry transmissions will also take place on 145.920
MHz SSB using the new 1kBPSK protocol developed by Phil Karn, KA9Q.

AMSAT will issue commemorative certificates to listeners who receive
the ARISSat-1 transmissions. Reports can be e-mailed to
Gagarin@arissat1.org or yuri@arrisat1.org. Include your name, call
sign, a description of what you heard and the UTC time you heard it.
Recording the battery voltage telemetry values and the UTC time you
received them will be especially helpful.

You can determine when the International Space Station will be
passing overhead by using the AMSAT-NA online pass prediction tool
at, http://www.amsat.org/amsat-new/tools/predict/.
NNNN
/EX

Monday, June 7, 2010

OH NO! UVB-76 Goes Off the Air! Duck and Cover!

From Wikipedia:

UVB-76 is the callsign of a shortwave radio station that usually broadcasts on the frequency 4625 kHz (AM full carrier). It's known among radio listeners by the nickname The Buzzer. It features a short, monotonous About this sound buzz tone , repeating at a rate of approximately 25 tones per minute, for 24 hours per day. The station has been observed since around 1982.[1] On rare occasions, the buzzer signal is interrupted and a voice transmission in Russian takes place. Only three to four such events have been noted. Despite much speculation, the actual purpose of this station remains unknown. On June 5, 2010, UVB-76 stopped transmission suddenly, the first time there is no signal received from UVB-76 since 1982. [2]

http://en.wikipedia.org/wiki/UVB-76

Tuesday, March 30, 2010

AA1TJ on Polyakov, Scrounging Parts from a Wehrmacht Tank, QRPp Success

Caro Bill, FB on your 20mW DSB WSPR DX! I've never actually been on the air during the upside of a solar cycle. This is wicked exciting! Thank you for the nice write-up on your Soldersmoke Blog, OM. I heard back from Fabio this morning; he seems to be as excited as I am (please see his message below). Italy is my fourth DX contact and third country with 10mW. Two weeks ago I worked F5NBX twice and FM5LD once. Again, all great fun... I'm glad to hear of your interest in the Vladimir Polyakov's mixer. I can attest to Vlad's claim about its resistance to SWBCI. So far, I've used silicon and germanium diodes, MOSFETS, and even a saturating inductor for the subharmonic, commutating switches. I haven't mentioned it till now, but leading up to my Gigi regenerodyne receiver, I built Polyakov reflexed 40m receiver that was lots of fun. The RF input signal first passed through a simple BPF on its way to the cathode of a triode, grounded-grid RF amplifer. The amplified signal next passed through the Polyakov anti-parallel diodes. The resulting AF signal was then re-injected into the grid of the same triode (now working as a common-cathode amplifier). In typical "reflex' fashion, the same tube amplifies first at RF and again at AF. Looking at my notebook entry, I was able to "plainly hear" a 1.0uVrms signal and in a week of operation I hadn't noticed any SWBC breakthrough. Actually, the subharmonic mixer was well-known by 1976, but I'd never seen it used by hams at HF until Polyakov popularized the idea. Our Eastern European comadres took a liking to it right away but it took some time before it finally caught on in the West. By the way, I had a short email exchange with Vladimir a few months ago. I'm pleased to report he's a really nice fellow. He happened to mention that his first amateur radio transmitter was built using parts that he salvaged from an abandoned Wehrmacht tank. It seems radio components were extraordinarily hard to come by in those days. Amazing... Have fun, Bill! Mike, AA1TJ ---------- Forwarded message ---------- From: Fabio Ventrone Date: Sat, Mar 27, 2010 at 9:16 AM Subject: Re: IZ0PEC de AA1TJ/QRPp To: Michael Rainey Dear Michael, Many many compliments for your qrpp station! Really exciting to have qso in this conditions... It's actually the first time I can connect qrpp oversea... Unbelievable, something we can tell our friends forever!!! I was transmitting with 4 el antenna and something more than 100w. I will have to take back my 817 and try to call dx as you bravely did!!! Best 73 qsl Fabio de IZ0PEC 2010/3/26, Michael Rainey > Dear Fabio, > > Thank you for your patience in copying my signal on 20m CW this evening. I > had been calling DX stations for several hours but you were the only one to > answer. My homebrew rig has an output power of only 10mW (0.010 watts). The > distance between us is 8793km; nearly one million km per Watt!. The antenna > here is simply an end-fed wire. > > I am amazed that you heard my 10mW signal in Rome. It's fantastic! > > Again, thank you for patiently listening for my weak signal, OM. It would > not have been possible without your very kind efforts. > > Ciao, > Mike, AA1TJ

Thursday, March 25, 2010

Polyakov's Russian Mixer

I'm planning on building a DC receiver for use with the WSPR system. I will probably follow W3PM's lead and put a crystal filter between the antenna and the mixer. This will be a fixed frequency receiver aimed at one 200 hz slice of the 30 meter band.

Of course, the big question is what mixer circuit I should use. I'll probably go with an SBL diode ring, but while perusing the literature, I again came across "The Russian Mixer" of Vladimir Polyakov, RA3AAE. Michael, AA1TJ, is a big fan of this circuit, and has been talking about it on Radio Havana Cuba. What a cool circuit it is! Just two diodes in parallel, cathode to anode. RF from the antenna goes in one side, and the local oscillator signal is placed at the other end. The LO signal causes the diodes to turn on and off on voltage peaks, effectively chopping up the incoming signal, producing sum and difference frequencies. LA8AK's drawing of one version of this circuit appears above. (Obviously OM AK didn't like this configuration, but it gives you the idea.)

The really cool part is that because you have two diodes, the "chopping" takes place at TWICE the LO frequency. This happens because on a positive LO peak one of the diodes conducts, and then, on the negative peak, the other conducts. So it is as if the mixer gate is opening twice each LO cycle. This allows you to run the oscillator at half the operating frequency, with advantages for stability and for the effort to eliminate common mode hum.

A while back I saw (somewhere!) a clever use of this circuit. LO was running at around 3.5 Mhz. With the two diodes in the circuit, it was a 40 meter receiver. They had a switch that could remove the second diode from the circuit. By throwing this switch, the RX went to 80 meters.

Does anyone remember this circuit? Where did it appear? SPRAT? QQ? Tech Topics? I can't find it.

I had the impression that OM Polyakov was active in the early days of radio. But some Googling shows that he is of much more recent vintage, still active and listed on QRZ.com. Here he is:

Friday, August 28, 2009

Sonya had The Knack

Stewart, G3YSX, sent us an article that he wrote some time ago for the Crawley ARC. Thanks Stewart. (This is an abridged version of the article. ) Very interesting:

Sonya
Sonya is the code name of Ruth Werner ne Kuczynski 1907 - 2000. Sonja is of interest here because her role in the GRU was as a clandestine radio operator. In her autobiography “Sonya’s Report” she gives a little insight into her work.

Trained in Moscow in the early 1930’s Soviet radio operators had to learn to build their own transmitters on site, using available materials. In rural China she and her accomplice (whom she lived with as husband and wife) set about building their first transmitter using receiver parts. There is an interesting story of how she had her real husband ship the transformer (a heavy 8 inch cube) up from Shanghai in the seat of a chair. Under the stresses of travel this nearly split from the chair which might have terminated her career as a clandestine radio operator before it started. This was the first of many incidents in which only luck prevented discovery of her activities.

Their first transmitter was a “three point” Hartley set, much improved by studying an amateur radio handbook of the time. It is not clear whether this was an oscillator, buffer, PA, whether she meant a Hartley transmitter that used three valves in parallel, perhaps that it was a single stage transmitter, with a two stage receiver in the classic paraset fashion. On the other hand it is known that she had a domestic set and it was not uncommon of them to be shortwave capable at that time. Building and setting up the transmitter must have been something of a challenge because she would not have had access to test equipment. In particular she implies that the transmitter was VFO controlled (presumably crystals were fragile and a security risk, both when making a boarded crossing and being on a fixed frequency). Under these circumstances getting setting set up on frequency must have been really difficult. I would imagine that this must have required her to find a reference frequency sent by control, net her transmitter and then send. Not easy with a power oscillator design and a receive that would be pulled by such a strong signal. The set had to be hidden when not in use. The Morse key was improvised out of a Chinese paperweight (actually a type of steel ruler) and a bolt and was dismantled during the day.

Antennas were not so much a problem because large outside receiving antennas were common. Ruth talks about asking permission from her landlord in Oxford to put up her antenna and receiving help from her unsuspecting host. From here text it seems that antennas were mostly long wires, although she talks about a “Fuch’s” antenna, a type that I am not familiar with.

In one house (in Warsaw I think) she started transmitting and this immediately blew the fuse for the house. She then had to quickly dismantle and hide the apparatus in the dark, lest her rented room be searched looking for the cause of the fault. In another apartment in Switzerland she had to close down and move sites (suddenly move house) because of EMC problems. Luckily (for her) one of her neighbours commented to Ruth that her husband (a Nazi) was sure that someone was operating a transmitter nearby which was causing interference to their radio receiver, and that he would organize a search later that week when he returned from a trip.

Ruth notes in passing that the absence of amateur radio traffic during the war was a problem because Soviet operators used to use it as a cover for their clandestine activities. It is not clear whether she was operating in the amateur bands giving the authorities too many Morse signals to monitor (unlikely because the non-amateur nature of the traffic would have been observed and reported by the radio amateurs), whether she was posing as a radio ham (again unlikely because of the tight regulation) or more likely, in my view, using our activities as a cover for both EMC problems and - to the unskilled – for strong local morse received on the shortwave bands.

In 1937 whilst operating out of Warsaw, Ruth talks of one evening when after setting up the transmitter, she caught here hand across the HT (two 120v batteries in series). She could not remove her hand without the help of an accomplice, by which time it was painfully burnt. She then got a hard time from her controller for failing to get a 50 group message out that night through extreme QRN. It later out that there had been a major solar even that night which had disrupted all radio communications. However she appears to have been working for the sort of organization that trucked no excuse, not even acts of
God.

Ruth would typically transmit at night between two and four times a week. Messages were 60 to 500 groups. Assuming 20 WPM with perhaps 30% time allocated to repeats and other procedure transmissions would have taken at least 45 minutes. In practice however, due to the difficulty of copying, transmissions often took half the night. It is therefore very surprising that she was never caught. In particular, given the hard time that the GPO gave the amateur radio community during the late 1940’s when she was handling the Fuch’s traffic, it would be very interesting to know why they never found her station in rural Oxford.

Ruth’s autobiography, which is out of print, but available from East Sussex libraries, unfortunately lacks much of the detail that one would have expected from a western text written so long after the event. This is undoubtedly a result of the excessive secrecy intrinsic to the other side of the Iron curtain even so long after the events, and which was maintained despite the obvious duplicity of her employers. This is a pity, because it would have interesting but harmless after all these years to have read more technical detail about both the transmitters and the operating procedure used by these agents.

Stewart G3YSX
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