Sunday, December 26, 2010

Very cool device

http://www.technologyreview.com/blog/arxiv/26194 or
http://arxiv.org/abs/1012.4415

This is a new nanoscale device that can detect RF.  You put in a bias current between D and S, it goes through the graphene (sheet of 1 atom thick carbon).  The graphene sheet resonates mechanically at an RF frequency (33 MHz in the reported device) when a signal is coupled in capacitively from the gate.  The vibration induces a signal on top of the D-S current.  The device works at 77 K (liquid nitrogen temperature), but hopefully can be developed for room temperature operation.

Friday, December 17, 2010

Ham Radio and Ngram

Google's new service "Ngram" is cool.  It lets you search for any word or phrase through all the books Google has indexed, displaying the count versus year.

Here is the graph for "amateur radio":

and here is the result for "ham radio":

The significance?  Ham radio (in books) didn't start until about 1950! The Ngram view page also gives links for the books in particular year ranges.  I looked up some of them prior to 1965 and found lots that were in the "popular" category: Popular Mechanics, Popular Science, Boy's Life, etc.  Amateur radio, however, has a book record back to 1900 if not before.

Locating amprnet

Remember ham radio's allocation of Internet address space?  (44.0.0.0/8) Thanks to xkcd, here it is in graphical form, ca. 2006 (red circle):


Right between Bell North and Japan Inet.  (Larger size at http://xkcd.com/195/.) You can buy a poster version of this at http://store.xkcd.com/.  (A good place to find gifts for the geek in your life.)

Sunday, December 12, 2010

ARRL 10 Meters

I thought I would skip the 10 M contest -- too much happening on the family / holiday front, and surely the band is going to be dead. Well...

BrazilImage via Wikipedia
I checked in this afternoon just to see, and by golly there were openings to the south (FL - Caribbean - Brazil) and to the west (XE and W6).  Along with some local folks.  I ended up with 16 mighty Q's and 13 multipliers.  And I resisted the temptation to use the afterburner!  Ten meters is a low-power band, right?

Now, I'm a believer in gray-line propagation.

Saturday, December 11, 2010

The End of IPv4 and the Amateur 44/8 amprnet

Internet Map. Ninian Smart predicts global com...Image via WikipediaI wrote about amprnet (ampr.org) a while back - here.  It's a relatively unknown fact that ham radio has its very own Class A IP network -- 44.0.0.0/8.  This is quite a huge chunk of Internet IP v. 4 address space -- 16 million addresses, give or take.  As best I can determine, it was established in 1987 to support future TCP/IP networks that might be implemented either on radio links or as some combination of radio and alternative commercial or other links.  (The latter makes a lot of sense now, given the widespread availability of consumer Internet connections.)  The allocation is best documented in this ARIN WHOIS link.  I have not been able to find on-line documentation or other material relating to amprnet, beyond a number of blog and email postings.  (I'd be happy to get pointers!)

This whole subject came up once again for me, when I was reading how ARIN is trying to "capture" (contractually speaking) the legacy owners of IPv4 address space.  These are people, presumably including amprnet, who received their allocations well before the current Internet bureaucracy was established.  An interesting look at the issues is available in ComputerWorld.  (Thanks slashdot!)

The amprnet allocation usage must be tiny in percentage terms, and hard to justify in a world of address scarcity.   Standalone radio networks based on TCP/IP (if there really are any!) are likely based on VHF if not 2.4 GHz (HSMM), and they are fundamentally local or regional and are not likely to be routable from the Internet.   They could probably equally well use a network address like 10.0.0.0/8.

In recent years, various other network-based amateur systems have developed, including EchoLink, IRLP, D-Star, winLink, etc.  These make effective use of Internet links, but have no particular need for the amprnet addresses.

I don't want to argue the pros and cons so much as to point to the odd situation of our hobby holding such a valuable resource, with no visible institutional support. 

What are the chances to get a little more RF spectrum, if we hand back the IP addresses?

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