KIX-OnlineLinks to amateur (ham) radio goodies on the web

As I’ve stated in the past, I’m fascinated by the use of radio communications by governments for espionage and wartime use.  When I came across this little nugget, I couldn’t resist.  What a joy it will be for those of us that can’t quite make it over to visit Bletchley Park.

The BBC has an article at:

http://www.bbc.co.uk/news/10239623

Bletchley Park (really hard to resist using “BP” for this one…..) has been trying to do this for quite some time.  Dwindling funds, repairs needed for the site have just made this one of those “round to it” projects. Many documents are too fragile to handle at this time and will take awhile to get posted online, but it will indeed make for a fascinating online resource.

I’ve had the pleasure of actually getting my hands on  real, wartime Enigma machine and it was REALLY NEAT!!!  You can read about it, but there is nothing like actually using one to get you even more interested in this topic.  Professor Tom Perera gives a number of great discussions at the New England ARRL Division convention in Boxboro Mass (I spoke to Tom at Dayton and he said there may not be a presentation this year).  His site is a HUGE wealth of information on this topic (and CW keys).  If you ever get the chance to hear him give a presentation – JUMP ON IT!!!!

His website is:

http://chss.montclair.edu/~pererat/telegraph.html

If you want to visit the actual Bletchley Park site and look at the offerings there, check them out at:

http://www.bletchleypark.org.uk/

I attended a great fox hunting presentation at Dayton this year, hence a few posts on the topic.

I had some posts in the past about tape measure beam antennas.  Really neat antennas and they have multiple purpose use (they are GREAT for hitting distant repeaters when you orient them vertically!).  Much like the picture on the right (courtesy of Joe Moell K0OV) they are more useful for fox hunting when you add the active attenuator to your setup.  FYI, Joe is the co-author of the great book “TRANSMITTER HUNTING, Radio Direction Finding Simplified” available where most ham books are sold.  His website has more information on the book at http://www.homingin.com/THRDFSinfo.html and he contributes to CQ and CQ VHF.

So….. just what is an offset attenuator?  Joe explains it on his “Homing in” site as:

An RF attenuator is a device that goes between antenna and receiver to reduce the signal strength down to within the range that the receiver S-meter can handle. Without one, you may think you’re close to the fox when you’re still far away. You won’t be able to get close enough to a camouflaged hidden T to identify it. The amount of attenuation should be adjustable so that you can add just a little when your S-meter first pins, up to a lot as you get within a few feet. Special ARDF receivers used by champion foxhunters have electronic attenuation built in, but ordinary handi-talkies don’t. Adding it would require major micro-surgery in the HT.

His attenuator page is:

http://www.homingin.com/joek0ov/offatten.html

I recommend his site in general, many great projects:

http://www.homingin.com

On his attenuator page, he has full schematics to make an offset attenuator.

But wait…… there’s more!

Further on his page, you see one made in a sweet Pomona box.  I like this box and thought it was a bit pricey at first, until I did the math and figured out the cost/time to do it myself.  These boxes are shielded with the connector of your choosing (BNC/SMA/259, etc).

They generally cost around $25 or so and are shielded!  Great to have.  When you add the cost of connectors and such, it isn’t really so expensive after all.

I really advise using such a case or a metal case in general, makes things work out much smoother in the end.  More information on this box at: http://www.pomonaelectronics.com/index.php?i=prodsub&parent=BOX&cat=BONCONN&getDetails=

But wait….. there’s even more!

Marvin Johnston KE6HTS is now offering a “semi-kit” for this attenuator on his website.  I’ve seen this kit when I was at Dayton this year and encouraged a friend to pick it up and build.  I may end up running a buildathon here in CT on these attenuators.

The price is really not bad at $22.00.  You can purchase them built for a few dollars more.

Information on the kits and pre-built models are at:
http://www.west.net/~marvin/k0ov.htm

And yep……. there’s even more (again!).

If you would like to “roll your own” from parts you may have on your bench, but don’t want to make a circuit board, you can get one from……. you guessed it…… Far circuits.  I picked one up and am going this route myself.

There are a few boards/projects on the Far circuits website at:

http://www.farcircuits.net/

There are a ton of great resources out there on the web, these will really get you going right from the start.  Fox hunting is a really fun and useful part of our hobby and one that doesn’t cost a ton of money to get started in.  If there are no active fox hunts in your area – start ‘em!  There are plenty of options as far as transmitters and such and really doesn’t cost a club much money to get started.

Spud guns or “potato cannon’s” have been around for a long time.  For some reason, I’m shocked that more hams don’t use them for putting up wires.  QST did an article awhile back on the topic getting people started, but not a lot of activity since (at least from what I’ve found online and locally).

The setup on the right here is the CSV19, instructions (and kits available) are on their website at:

http://www.antennalaunchers.com/csv19/csv19asm.html

There is a ton of information on the web.  Unfortunately, a lot of what used to be freely available ended up not being so anymore since people decided to make businesses out of sites that used to give the information away – BAD WEBSITE!  BAD!

Anywhooo……

There is still some other interesting sites with plenty of information.  On that end, I send you to Philip Mayfield.  He has a site with full details on various methods, air displacement, etc. on his site at:

http://www.sigmazone.com/TennisCannon_FullFactorial.htm

I’ve limited this to pneumatic cannons for a reason, the combustible versions are VERY simple.  I just don’t like the mess they leave behind (though they are fun).  Combustion mortars are fun too……. but I digress…..

There is a FANTASTIC video with step by step instructions courtesy of Patrick Norton (of ZDTV fame, then on various shows on the Digg networks).  He did a video on Systm (now canceled program) that is still freely available online – SWEET!

The video below is also available as a downloadable file:

If you want to download the show, or read show notes, visit them at:

http://revision3.com/systm/tennis

If you know of any other resources available online, please post in the comments.

First off…. sorry for the delay in posting (never took three weeks off before).  As the Amateur Radio Emergency Service District Emergency Coordinator, we had a TON of public service events and I had a couple of public speaking engagements (radio related), soooo………….  But I plan on posting several posts to make up for the shortfall – there is just too much interesting stuff for amateur radio ops on the web!

Which brings me to the Annenberg Project and their series “The Mechanical Universe and Beyond”.  Really great series and I’m thinking about purchasing on DVD for some of my classes – there’s a ton of information here that will indeed pertain to hams.

The course description reads:

This series helps teachers demystify physics by showing students what it looks like. Field trips to hot-air balloon events, symphony concerts, bicycle shops, and other locales make complex concepts more accessible. Inventive computer graphics illustrate abstract concepts such as time, force, and capacitance, while historical reenactments of the studies of Newton, Leibniz, Maxwell, and others trace the evolution of theories.

But, in the middle of the course are some good videos for new hams (and those that want to reinforce some of the theory in radio physics):

14. Potential Energy
Potential energy provides a powerful model for understanding why the world has worked the same way since the beginning of time.

15. Conservation of Momentum
What keeps the universe ticking away until the end of time?

16. Harmonic Motion
The music and mathematics of periodic motion.

17. Resonance
Why a swaying bridge collapses with a high wind, and why a wine glass shatters with a higher octave.

18. Waves
With an analysis of simple harmonic motion and a stroke of genius, Newton extended mechanics to the propagation of sound.

28. Static Electricity
Eighteenth-century electricians knew how to spark the interest of an audience with the principles of static electricity.

29. The Electric Field
Faraday’s vision of lines of constant force in space laid the foundation for the modern force field theory.

30. Potential and Capacitance
Franklin proposes a successful theory of the Leyden jar and invents the parallel plate capacitor.

31. Voltage, Energy, and Force
When is electricity dangerous or benign, spectacular or useful?

32. The Electric Battery
Volta invents the electric battery using the internal properties of different metals.

33. Electric Circuits
The work of Wheatstone, Ohm, and Kirchhoff leads to the design and analysis of how current flows.

34. Magnetism
Gilbert discovered that the earth behaves like a giant magnet. Modern scientists have learned even more.

35. The Magnetic Field
The law of Biot and Sarvart, the force between electric currents, and Ampère’s law.

There’s more, but this will give you an idea of the valuable resource.  The video clips are viewable online (though rather small).  I haven’t inquired yet as to the cost of the course on DVD.

Available at:

http://www.learner.org/resources/series42.html?pop=yes&pid=587#

Post update:

I have found the link for the cost of the series – $450. YIKES!

http://www.learner.org/catalog/series42.html

So, here I was at Dayton a few weeks ago and decided to check out the fox hunting/amateur radio direction finding (ARDF) forum.  I forgot who did the forum, but it was actually very well done.  One of the projects I learned about was “The Montreal Doppler”.  This is a really neat project designed by Jacques Brodeur, VE2EMM.

I saw many neat attenuators, offset attenuators….. but this….. well…. it has LEDS!  Pretty lights…. OK, I digress.  Working with a bunch of these LED’s is pretty kewl and looks sweet.  This is a project that is well documented on the web and I’ll provide links below.

The biggest question I had was, where do I get the microcontrollers and firmware.  Not only was I able to acquire the PICS (microcontrollers), but I was able to get PC boards and the LCD for a very reasonable price from FAR Circuits!  I know I picked up the last one he had at Dayton, but he may be able to do more (they cost $45.00).  Check out the FAR circuits website at http://www.farcircuits.net/

A little about this project from VE2EMM’s website, list of features:

-   36 LEDs display; center LED when green = good signal, when red = no signal ,  the direction is frozen to the last good signal.
-   Uses 3 PICs; a PIC16F628A for the display, a PIC18F4520 as the main processor and a PIC12F675 as a frequency divider.
-   Filters; a Max 267, the best bandpass filter that I have ever seen, followed by the Roanoke switch cap filter for very narrow band width (+/- 0.5Hz).
-   My DopplerII integrating and phase detection software in the main PIC.
-   LM386 for monitoring the audio independently from the doppler.
-   Simpler menu selection, turning a selection pot and a pushing a DO switch.
-   It will switch 4 antennas with a + or – going signal, 4 antennas differential, 8 antennas with a + or – going signal.
-   Pushing the DO PB sends the direction to APRS.  The protocol is:  <cr><lf>%359/Q<cr><lf>. The Q (0<8) is the quality of the signal just before the
extraction of the phase information.
-   GPS information goes through the doppler, it will be instantly interrupted when the doppler sends a DF to APRS on a PC.
-   Faster main processor, PIC18F4520.    **** NEW ****  June 06

The model I saw really intrigued me and there are a few really well done websites devoted to this project (it has quite the cult following).

The original site is at:

http://www.qsl.net/ve2emm/pic-projects/doppler3/doppler3-e.html

Here is another page on Jacques site that has some examples from other builders:

http://www.qsl.net/ve2emm/pic-projects/doppler3/md3_photos/dopler%203%20pictures.html

KA7OEI has a neat page with a bunch of information on this project:

http://ka7oei.com/emm3.html

He has a lot of information about an alternate firmware that looks like the image below:

The alternate firmware page is at:

http://ka7oei.com/emm2_mont2a.html

If you have any more information on this project, resources or anything of the sort, please comment below.