[ARC5] Unusual BC-221

[Roy Morgan]

On Mar 4, 2015, at 4:46 PM, Bill Cromwell <wrcromwell at gmail.com> wrote:

> Hi Roy,
> 
> A couple of other hams asked about the same thing in private posts…. I will make it a priority to put together some kind of small "document" to better describe what I did.

Bill,

Thanks for the reply - this is a “nice-top” type project not a gotta-do, so give the cat on the hot tin roof priority!


> I think "Spectran" or "Spectrum Lab" (also known as "SpecLab") are the best choices...I run Windows programs on WINE in my Linux boxes.

I know there is a way to run win doze on a Mac. At least some of the computers at the local community college will boot either way.  I’ve never ventured into that arena though.

> I'm sure *everybody* can run them regardless of their favorite operating system.

It appears that neither Specran nor Spectrum Lab runs under Mac OSX.  However I did locate an also-free similar system called 

iSpectrum - Macintosh Audio Spectrum Analyzer  at:
http://www.dogparksoftware.com/iSpectrum.html
“iSpectrum is an easy to use audio spectrum analyzer that allows you to view live audio in a standard frequency plot, a stereo oscilloscope view and a waterfall display."

You can adjust the display resolution, center frequency and save images to disk.

iSpectrum is used by Amateur Radio Operators, Audiofiles, Musicians, Sound Technicians and Educators.

> ...Fldidgi might not work well for this since it doesn't have a spectrum display.

Right.  It does have a waterfall display but not the spectrum one.  I have been using it to decode the internet “broadcast” of teletype signals (called ITTY) “from Sequim Washington”.  It does a fine job of that, and apparently will decode and generate many of the digital mode signals that hams use.

> The waterfall - a kinda-sorta spectrum display - might not get you as close but we can give it a try.

I think I’ll try the iSpectrum.  It seems like the most straightforward way to get the frequency display.  It has a list of features, including:

	• Audio spectrum analyzer.
		• Spectrum Display.
		• Waterfall Frequency Display.
		• Oscilloscope View.
	• 6 User selectable bandwidth resolutions.
	• User selectable center frequency.
	• User selectable input gain.
	• Works with built-in, system and USB microphones.
	• Displayed images can be saved to disk.
	• Point-and-click frequency marker.
	• Auto centering of marker frequency when switching bandwidth.
	• Choice of FFT window functions.
	• User selectable sample averaging.

> Now posting to my whiteboard so I don't forget!

The first thing for me to do is to get the LM out of its box and set up.  I do want to check it’s crystal calibration - at least roughly at first, then later when I get the spectrum software and computer lashed up, with more accuracy.

This is all very interesting: combine the exquisite true boatanchor technology of 1944 with the up to date 32 bit computer fast forrier transform running on an Intel powered laptop!

Roy Morgan
k1lky68 at gmail.com
K1LKY Since 1958