Tuesday, December 10, 2013

How Long is a Nanosecond? (Grace Hopper aka Amazing Grace)

[I originally posted to a mailing list I'm on.]

Google's doodle for today (December 9th, 2013) is commemorating Grace Hopper's birthday.

Time.com has a pretty good summary here:

I suggest watching/listening to the 2 minute youtube video. One of the things she is known for is talking about how long a nanosecond is by giving away 11.8 inch lengths of wire, which is how far light can travel in one nanosecond.

Part of the reason for talking about this is to explain the delays in communicating through satellites.  Though the most direct relevance is in computer (and now most modern microelectronic) engineering and training programmers.

It's a good reminder of how intertwined electronics, physics, and software are and how almost every device we touch today has some sort of microcomputer (microcontroller) running software it.


Adafruit Products of particular interest to Amateur Radio DIY Projects

[hopefully I will come back and expand this post a bit later]

Adafruit.com has a few products that are of particular interest to me for amateur radio DIY projects.
These products have been well research and seem to be currently best-in-class to me. Read the product pages and tutorials on the Adafruit site to see what I mean. The projects I'm thinking about are:
  • Yaesu VX-8DR
    • DIY GPS Module with the Adafruit GPS Module.  The stock Yaesu GPS seems to be overpriced and is reported by many to underperform.  The Adafruit Ultimate GPS seems like it should do a much better job, but the VX-8 seems to have bugs in it's parser so it requires some field padding that is particular to the Yaesu GPS.
    • Bluetooth Serial Link to use an Android Phone's built-in aGPS via a serial bluetooth connection.
  • Yaesu FT-857D
    • Bluetooth Serial Link
      • Eliminate the need for the direct CAT cable connection for better isolation from the computer
      • Rig control via an Android Phone app. The FT-857's small control panel has a number of compromises. The stock radio mic doesn't have a keypad for direct frequency entry.
  • Uniden BC346XT Scanner
    • Bluetooth Serial link for logging scanner activity. Hopefully this will let me get the scanner farther away from the noise generated by the computer while still allowing me to log hits.
Hopefully I'll be back soon to log my progress.

Best Chinese Dual-band HT? (Good amateur radio blogs)

Here is a good run down of which Chinese HTs are the top performers in a number of categories from Hans, PD0AC's Ham Gear Blog. The Wouxun which I've been very happy with since 2011 rates pretty well. I still need to pick up a Baofeng one of these days for comparison.
Hans' Ham Gear Blog is a great source of reviews and tests of radios, mostly the new crop of inexpensive gear from China. Anyone who is interested in new radio gear should follow his blog. While there seems to be a new model coming out everyday many are just repacking of the same components.  Hans identifies many of the common cores for each radio. Even though this post will be quickly dated in some ways, the cores of these radios, especially the system/radio-on-a-chip that enables the low prices don't change that often.

Good Amateur Radio Blogs to Follow

There are a number of really good amateur radio blogs to follow.  Some of my favorites in no particular order are:
 Dan Romanchik, KB6NU, has a post of what he considers 10 Great Ham Radio Blogs.  My opinions overlap with his a bit, though I haven't yet gotten into QRP.

I post some of these things here because I usually I can find things most quickly via google.  Then when it takes my a whole bunch of tries to find what I was looking for again, I think I should be posting this stuff for others as well as myself.