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Tuesday, December 28, 2010

Blue Light in Dark Ice

Down in Antarctica, the "Ice Cube" neutrino telescope was completed this month. It is an amazing piece of gear in an awesome location. Essentially, they use a 1 kilometer square piece of pure Antarctic ice as the detector -- when a neutrino hits a water molecule, it makes a bit of blue light and from this light the direction of the neutrino can be determined. But there is a problem: cosmic rays can create the same kind of blue light. So there's noise. They need a filter, right? Yes, and for this purpose they use... THE EARTH. They put the blue light detector at the TOP of the cube and look DOWN, down through the Earth! Only neutrinos get through.

For more details: http://www.icecube.wisc.edu/info/explained.php

Friday, December 24, 2010

R/C Plane with Camera over New York City


This is really amazing. You should watch it in HD. 120 mile range? Maybe from the top of the Empire State building, right?

More info here:

http://singularityhub.com/2010/12/21/breath-taking-aerial-video-footage-from-new-york-city-taken-by-a-rc-plane/

Thursday, December 23, 2010

DXers: What is my path to VK6XT?

I've been looking with pride at the WSPR map (below) showing that my little beacon has been received by far-off VK6XT. He picked me up again this morning, again only once. That makes three days in a row, each day only one report. Each time VK6XT is the only station in the Oceania area receiving me. And each day the my signal makes the trip around 1025 UTC. Now, I'm not a skilled DX'er, but it seems obvious to me that we are dealing with grey-line propagation here, right?

The image above shows the view from the sun at 1025 UTC today. Obviously the day/night terminator is along the perimeter of the earth in this image. So, I guess my little sigs could have been travelling either short path over Northern Europe and down over South East Asia OR they could have taken the long trip down over South America, over Antarctica, and on to Perth. My guess is that the short path is more likely. In any case, as cool as it is, the map drawn by the WSPR system is not how the sigs actually travelled.


I hope you DX hounds out there will chime in and tell me if I'm on the wrong path here...

Wednesday, December 22, 2010

The Payoff from WSPR

TimestampCallMHzSNR
GridPwrReporterRGridkmaz
2010-12-22 09:28 N2CQR 10.140215 -28
FM18jv 0.2 VK6XT OF86td 18576 288
2010-12-21 10:28 N2CQR 10.140221 -28
FM18jv 0.2 VK6XT OF86td 18576 288

I know some of you guys consider WSPR kind of weird, kind of narcissistic, more like broadcasting than real amateur radio. I hear you. As creator Joe Taylor himself has pointed out, these are not really QSOs. But I have to tell you, it is very satisfying to walk into the shack, and, with coffee cup in hand check the WSPRnet screen to see who has recently received your little QRPp signal.
For the last two mornings, I've found VK6XT receiving mine. That's 18,576 kilometers covered by 200 milliwatts to a low dipole. In Western Australia my signal is 28 db below the noise (that means below the noise in a standard SSB passband). I see that I'm making the trip only once each day, at around the same time, and that VK6XT is the only Oz station picking me up. Very cool.

Here is Richard, VK6XT, the fellow at the other end of the path:

I was born in Christchurch, New Zealand in December 1954. Keen on shortwave as a boy, I went to Rangiora High School and met Gary Watson ZL3SV who sparked a lifelong interest in Ham radio. However Life intervened and it wasn't until 1976 in Wollongong, Australia that I first transmitted as VK2NNL.(after a brief fling on The illegal CB band). I upgraded and then returned to NZ to become ZL1OK from Rotorua. I became a DX hound and worked 256 countries for DXCC. The high point of my DX activities was in 1991 when I organised a DX-pedition to the Auckland islands. We operated as ZL9DX / ZL9YL and Kerry operated ZL9TPYon 6 metres. Always keen on home brewing and QRP gear I now work in Perth as a Design and Technology Technician. My ham radio activity is at present operating an Icom IC7400 to a variety of antennas 160m to 2m. . I am keen on the digital modes, especially PSK31, and spend my spare time on my hobby farm near Katanning(300 kM south of Perth).

Tuesday, December 21, 2010

Ham Radio Time Capsule at University of Virginia

Bert, WF7I has been sending us some great info from the University of Virginia's radio club. Listeners will recall his adventures in putting up and taking down the rhombic antenna. This week Bert sent in excerpts from his research on the history of the UVA club. This bit came from Lee, KD4RE. I know there are a number of "anchor-ologists" out there (fans of the Boatanchors i.e. big, old tube radios). I thought you guys would get a kick out of this. Oh, wouldn't you want to find a room like this one?

Back in 1971 a student named
Bill Hughes was Ham and knew I was a ham
and he wanted to get the UVA Ham radio club started up again. There
were a couple of other Hams around, Dave Wolfe who was Chief Engineer
at WTJU before me, has a 2-B receiver in the engineering (transmitter
room) at WTJU when in was in the basement of Humphreys.
(Yeah I have a lot of WTJU Stories..).. Anyway Bill told me he heard
that the last active ham radio club had been located over in one of
the ground rooms behind Varsity Hall (which has since been moved to
make room for Rouse Hall expansion) In those days it was the Air Force ROTC building. Anyway, the ground level had a brick floor and sort of an open portico and across the back were a bunch of rooms (all brick of course). well we came to the old door and saw open wire feeder remnants overhead We opened the door and it was like opening a time capsule - There in the room was mostly 1930s and 1940s vintage gear, I guess it had not been used since the mid 1950s (or early 1950s).

There was a rack with an AM transmitter in it, sort of a copper
colored paint on the front and on it was a piece of cardboard with the call sign W3VA. There were a number of old receivers in the
room I recall a National HRO with its plug-in coils there was and RME
receiver with a tunable preamplifier/selector as a separate box, and
several others. I am not sure but the DX 100 we had for a while may
have come out of there so that would have been late 1950s then...

For more UVA Radio Club history go to:
http://www.student.virginia.edu/~w4uva/file-storage/history/index.html

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Monday, December 20, 2010

AL7RV's Zenith Transoceanic from Vietnam days

Bill,

Glad the junk box is providing useful. Enjoyed your Blog about the great Ham Radio day you had. I got the same feeling when my Paraset 350v power supply came alive without letting any of the all important 'smoke' out. I did get 'bit', and had a flashback to the days of my youth that involved my Weller Soldering gun and a GE tube manual. I tried to build every circuit in the back of the manual and got 'bit' by most of them. Heck the shocks keep our batteries charged right?

I'm side tracked on a project to construct a 455Kc BFO for a Zenith Trans-Oceanic 3000-1. I purchased the radio at the Tan Son Nhat BX/PX during my first month in country. (~68). The radio spent a year in Vietnam and a little over two more years in Thailand. Used to wrap my fatigues carefully around it and pack tightly in the center of my duffel bag. Held up pretty darn well.

I've dug the radio back out and am having a ball with it. It's helping me a LOT with my Spanish language relearning efforts. But I do lament the lack of English programming on shortwave today.

The Zenith became our main source for news rather then the much edited and heavily censored AFRN. I would patch the audio output of the radio into a spare MUX channel going off to another signal site and they would in turn patch it to other sites in Vietnam. I head stories that in some camps the local AFRN low power FM radio transmitter feed would be pre-empted with the BBC World News that was coming from my Zenith.

Hey, are you enjoying the cold weather! hihihihi...

73 -- Natchez Jim

Saturday, December 18, 2010

Computer Successfully COOKED!

I must say, this was one of the strangest repair jobs I've ever had: You may have heard the background: My wife's three year-old Sony Vaios 'puter suddenly came up with really serious graphics problems. A quick Google revealed that lots of computer have this problem (lots of brands... including Apple). We took the computer down to the Sony store and they got all legalistic on us. Yes, it was clearly the video card. Yes, Sony had agreed to fix the video cards. BUT unfortunately Sony had not put our model number on their list of computers that they would fix. So they wanted to charge us $400 to fix the problem. No thanks Sony! Goodbye Sony!

Inspired by the iFixit poster on the wall of my shack, I did some more Googling. Soon I'm reading messages from all around the world recommending that I -- in one way or another -- cook the computer. But why? Is the problem IN the GPU chip? Or is it in the solder connections between the chip and the board.

Gents, you'll be pleased to learn that this is a SOLDERING problem. Looks like NVIDIA used a bad mixture of soldering types. There is apparently little blobs of solder on the baord, and little blobs of solder on the chip. LOTs of little blobs. Surface Mount to the MAX! But they used two different solders and this causes the connections to fail far more quickly than they should have. Here are the details:
http://s0.2mdn.net/2994486/Polycom_inquirer.html?rfp=http://www.theinquirer.net/inquirer/news/1004378/why-nvidia-chips-defective
Enter the oven solution. The idea is to simply re-heat the chip and make the solder at the connections melt again!

YouTub presents lots of different ways of doing this. I like the idea of using a bright lamp to administer the heat. I used a 120 watt Halogen beam lamp. The kind that you see on lights for the backyard. I tested its heating properties on a chunk of 60/40 rosin core solder. At about 1/2 inch it melted the solder in 30 seconds.

I put the beam on the TOP of the chip and gave it about 30 seconds of burn. Then I administered some heat sink compound, vacuumed out the fan, and put the computer back together.

IT WORKED! That computer is now working just as it had before. This was a very satisfying repair, but there was no real troubleshooting, so it wasn't really up there with my favorite fixes.  You can check out www.computerrepairtraining.org if you want to learn more about fixing computers.

I'll put one of those cheap laptop coolers underneath it. I'm guessing that this thing will go for another few years.

Thanks to all who provided advice. Thanks to ifixit for the inspiration. Thumbs down on Sony. BOOOOO! HISSSSSS!

Wednesday, December 15, 2010

Should I Put My Sony Computer in the Oven?

In a recent podcast I asked for help with my wife's ailing Sony Vaios computer. The graphics card has gone toes up. Sony acknowledges that they had BIG problems with the NVIDIA graphics cards, but even though our computer has an NVIDIA graphics card and has all the symptoms that come with the NVIDIA graphics card problem, because our particular model is not on their list of affected computers, they won't fix it. (Mental note: Don't buy any more Sony computers!)

Anyway, KB1SNG recommends putting the mother board in the oven:

As crazy as it may sound, you could try putting the motherboard in the oven.
Many people (including myself) have tried this with success.
I did it a while ago, and I can't remember if this ( http://www.overclockers.com/forums/showthread.php?t=606658 ) was the guide I used or not, but it should suffice. If I find the other link, I'll post it here.73,Nick LaPointe, KB1SNG

Rogier provides this useful info:

NVIDIA lost a lawsuit with regards to a faulty graphics Chip. Caused by the fact that when they started using lead free solder.
This new solder turned out not as heat resistant as thought and tends to break loose causing the chip to fail.
He continues:
Hmm that's a bold move to put the board in the oven.
On the other hand there is little to be lost and you might give it a try.
Thinking of it I rather apply the heat locally. Isolate the Graphics chip from the rest and apply a short blast of heat to the chip.
Perhaps with a hot air paint stripper....

So what do you guys think? Should I pop it in the oven? Or apply some heat? I kind of like the idea of fixing a problem caused by lead-free solder (yuck).

Tuesday, December 14, 2010

Immediate Gratification: WSPR shows results very fast

So you build or modify a rig and you put up a new antenna and you then spend some time wondering if you're really "getting out," right? Well, wonder no more my friends! WSPR provides almost instant feedback on your work! Here is what the display looked like for my station a short time after I connected my modified transceiver to my new 30 meter dipole. Pond crossings were rare events before.

In my last post I asked if there were others running homebrew gear on WSPR. I am not alone! Paul, M0XPD, has put together a rig far more sophisticated than mine. Paul writes:

You ask if there are any others running h/b in WSPR...
My 50mW multi-mode beacon runs WSPR, DFCW and S/MT Hell on a 10-minute, frequency-hopping cycle.
It is entirely stand-alone - severing the umbilical cord to the PC gave me a really good feeling!
I'm currently working on a set of filters (BP and LP) to allow me to run on other bands (currently I'm on 30m).
Description on my blog: http://m0xpd.blogspot.com

Sunday, December 12, 2010

A good radio morning at N2CQR

Today I had one of those really good ham radio mornings in the shack. My objective was to add one more amplifier stage between the balanced modulator and the power amplifier in my Roman WSPR DSB Direct Conversion transceiver. First I had to take the balanced modulator (trifilar transformer and two diodes in a singly balanced configuration) off the board and move back, closer to the AF input jack -- I needed to make space for the new amplifier stage. For that stage I consulted Doug DeMaw's books and Wes Hayward's EMRFD. I went with a feedback amp using a 2N3904 in Class A.

With coffee brewed and with my Drake 2-B tuned to the very congenial DX-60 net (75 meters AM on Sunday mornings), I turned to the junk box. It was like meeting old friends! I pulled out parts that Michael, AA1TJ had sent me. I pulled out others that had been sent by Jim, AL7RV. I got out my box of isolation pads that Jerry Felts, NR5A had sent in. Soon the parts were glued and soldered to a board that already had an AF amplifier designed by Roger Hayward, KA7EXM and a PA that is my "Manhattan-ized" version of Tony Park's SDR rig PA. At the center of the board is little Colpitts oscillator that I took from a WSPR rig designed by Gene, W3PM -- earlier in the week Gene had posted a comment on this blog saying he was pleased to see my call on his WSPR screen. I wonder if Gene realized that he was seeing the signal from an oscillator from his design! The laptop was provided by a listener who prefers to remain anonymous -- thanks OM! Nearby, a copy of "Lid, Kid, Space Cadet" by Jeff K1NSS provided encouragement.

The rig passed the smoke test so I moved it over to the operating position and put it on the air. I got immediate gratification: the WSPRnet map right away showed my signal (now around 200 milliwatts) being received all round North America. You can watch this LIVE by going to http://wsprnet.org/drupal/wsprnet/map Just plug N2CQR into the "Call" box and hit UPDATE.

I know that WSPR is not everyone's cup of tea, but I like it. It was fun to build this rig. While WSPR is almost exclusively a mode that uses store-bought equipment, I get a kick out of being one of very few ops using a homebrew transceiver in this mode. (Are there any others?)

Next steps: I need to figure out how to set up automatic switching (by the computer) from transmit to receive. And I want to make some PSK-31 contacts with this rig.

Thanks to all who contributed!

73 Bill
Designer: Douglas Bowman | Dimodifikasi oleh Abdul Munir Original Posting Rounders 3 Column