HRDX Interviews Paul Taylor VK3HN

Wow, Paul Taylor, VK3HN is working on homebrew rig #11.  FB.  

This interview was quite thought-provoking. 

-- I agree with Paul about the importance of not being dogmatic about 

always staying under 5 watts.  It sounds like Paul is having fun with his 

100 watt SOTA project. 

-- It was great  to hear that Leon VK2DOB is still active in ham radio and running a QRP company in VK.  FB.  An article by Leon on CMOS mixers in the summer 1999 issue of SPRAT played a key role in my understanding how switching mixers really work.  I put Leon's diagram in my book SolderSmoke -- Global Adventures in Wireless Electronics. 

-- On blowing up the finals in simple HB gear.  The first real transmitter that I built was the VXO-controlled 6 watter from QRP Classics by the ARRL.  It had a 36 volt Zener diode across the collectors of the final.  This was to prevent the kind of final destruction Paul suffered up on that summit:  "D2 is used to clamp the collector voltage waveform to protect the output transistors if the transmitter is operated into an open circuit or high SWR antenna system."  Maybe we should revive the use of that simple SWR protection circuit, especially for SOTA rigs. 

Wow! Great Article on the Wow SETI Signal

Thanks to David Umbaugh (and his son!) for alerting me to this really great article in The Atlantic on one intrepid amateur who has chosen to follow-up on the famous (and possibly extraterrestrial) "Wow" signal.   You will like this article. 

http://m.theatlantic.com/technology/archive/2012/02/the-wow-signal-one-mans-search-for-setis-most-tantalizing-trace-of-alien-life/253093/

Robert Gray's book is available here:

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20

QRO Problem, and THE KLUGER

Hi Bill,

I've been enjoying your podcasts for a couple of years now and have read both of your books. Please keep up the good work it is much appreciated. In fact, as I can now have both your books and your podcasts on my iPod they are quite literally held close to my heart.

Inspired by your "Kludge Controversy" - enclosed are a couple of photos that I took while on Mount Wellington in Tasmania.


THE POWER OF RADIO

Mount Wellington is a high mountain and is a good launch point for radio waves over the city of Hobart. The visitor lookout has this fantastic warning sign "Electronic disturbances to your vehicle" warning that the transmitter on the mountain can seriously interfere with your car and it may not start, the doors may not open, and the immobiliser may permanently immobilise it. The advice is "A metallic sunshade may reflect radio waves away from the vehicle" and allow you to start it. I'm sure your QRP rigs need no such dire warnings!

WHAT WERE THEY THINKING

And in the very same car park I see this car called a Kluger. In what flavour of English is that a good idea? I know the Brits and Yanks differ over a few phrases but I've never before come across an Oz word that means the exact opposite.

Thanks again for all your many inspiring "broadcasts", and may the Magic Smoke (http://en.wikipedia.org/wiki/Magic_smoke) always stay where it should!


Steven
G6VRD


Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20

Some unbridled Australian enthusiasm... (Two Videos from Oz)

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics"http://soldersmoke.com/book.htmOur coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmokeOur Book Store: http://astore.amazon.com/contracross-20

Australian Antarctic Antenna Archeology

Macquarie Island

Bill,

I caught half of a report on “The 7:30 Report” on Australia’s public broadcaster ABC TV. Not knowing the full Mawson expedition story, I found this interesting. A conservation group is working to conserve the old halfway point radio repeater mast and whatever other bits have survived on Macquarie Island.

The links are to the transcript and the actual report video.

Story Transcript:

http://www.abc.net.au/7.30/content/2011/s3268909.htm

Vodcast videos. They are about 26MB in size. Theyr’e both the same video. Just two different formats.

http://mpegmedia.abc.net.au/730report/video/podcast/r799754_7027600.m4v

http://mpegmedia.abc.net.au/730report/video/podcast/r799754_7027588.wmv

John Dowdell

Yet to do the test

Sydney Australia

Grote Reber, Radio Astronomy, and Tasmania

Wow, the website of the National Radio Astronomy Observatory is a real treasure trove, with lots of ham radio info. Check out their page about ham radio's contribution to the exploration of the universe: http://www.nrao.edu/whatisra/hist_ham.shtml

The picture above shows antenna that Grote Reber built in his backyard in Wheaton, Illinois in 1937. It is now on display at the National Radio Astronomy Observatory at Green Bank, West Virginia. That's quite an antenna! Imagine the neighbors' reaction.

NRAO has a page devoted to Grote Reber:
http://www.nrao.edu/whatisra/hist_reber.shtml
I had wondered what had drawn him to Tasmania later in life. Here's the answer:

In the 1950s, Reber sought a field that seemed neglected by most other researchers and turned his attention to cosmic radio waves at very low frequencies (1-2 MHz, or wavelength 150-300 meters). Waves of these frequencies cannot penetrate the Earth's ionosphere except in certain parts of the Earth at times of low solar activity. One such place is Tasmania, where Reber lived for many years. He died in Tasmania on December 20, 2002.

Lasers, LEDs, Tin-foil Hats, and QRP

Yesterday I got a very interesting message from Rye, K9LCJ. The map of Tasmania comes from the Modulated Light DX portion of the KA7AOI site (below).

Hi Bill:

I really enjoy your Solder Smoke show and news feeds. Great stuff that has got me back into ham radio again. Your note about optical comms got me fired up enough to add some notes that you might not be aware of.

There is a substantial worldwide community playing with optical communications and they have achieved some amazing records using simple off the shelf components – mostly big Luxeon LEDs which have some (debatable) advantages over Lasers. The most sophisticated component in typical systems is the Fresnel lens – which can be obtained at office supply stores or ebay as “page magnifiers” for a couple of bucks.

There seem to be about four major groups:

The Radio and Electronics Association of Southern Tasmania has an active bunch and they have achieved some great distance records with (QRP) LEDs. They have also been bouncing signals off of geographic features to establish communications paths. They are also doing some cloud/sky bounce things that are quite amazing. The REAST web site has lots of well documented test data that’s really interesting to read.

K3PGP has an exceptional web page full of test reports and construction details. His K3PGP preamp/receiver (and variants) are the basic building block for most systems. It uses a $1.00 pin diode, a MPF103 FET and a handful of common parts to get some almost fantastic performance.

Yves, F1AVY has a strong theoretical background and has been doing interesting stuff in France for quite a while and his web page has lots of interesting technical details.

Clint, KA7AOI has a very comprehensive web page. Clint holds the record for long distance communications (173 miles) and describes much of his equipment and testing. There is also a bunch of historical material that is very interesting.

There are probably a bunch of folks I have forgotten, but all of them are noted in the many and varied links found on these web sites.

I think that the most interesting thing about the activities is how the teams have adapted available technology to an interesting problem. Much of the work resembles current amateur weak signal activities. In fact, Spectran and WSJT are part of almost every activity. Much of the work is unique outside of the academic community and might even be called groundbreaking in some areas.

We have a small group here in the Raleigh North Carolina area, but so far we haven’t done anything of note other than build equipment and play in the local park. The fact that this sort of thing must be done outside at night draws all kinds of attention – some of which is not necessarily good. …a bunch of strange looking guys running around in the dark with strange flashing red lights…. I have a special cap that I wear for the occasions.

Keep up the good work.

Rye Gewalt

K9LCJ