[aprssig] Re: *** APRS TNC Test CD Now Available *** Updated Info

Christopher T. Day CTDay at LBL.Gov
Tue Oct 31 10:28:50 CST 2006

It turns out that the Nero version is working for me after all; I was
misunderstanding how the mixed mode CD would appear in the various
playing software. The CD Player does not appear in my
Accessories/Entertainment menu. [Windows XP Pro] I used the trick
suggested on this list earlier of using MediaPlayer to rip the disk,
abort the rip, then go back and play the tracks.



            Chris - AE6VK




From: Stephen H. Smith [mailto:wa8lmf2 at aol.com] 
Sent: Tuesday, October 31, 2006 1:24 AM
To: TAPR APRS Mailing List
Cc: dave at emv.co.uk
Subject: [aprssig] Re: *** APRS TNC Test CD Now Available *** Updated


dave at emv.co.uk wrote:

The track numbering is a bit odd.  Track 1 is very short and blank,
track two announces itself as "Track One" , track 3 announcement is
"Track Two" and so on....
The "De-emphasised" audio is "very" muffled, compared to what comes out
of the rig speaker jacks hear in the UK.  I'm not aware of any US/EU
differences in Ham FM radio charactersisics, but I suspect some TNC's
will struggle with the "De-emphasised" tracks, where as they will work
just fine with a real FM radio speaker jack feed.  I have a collection
of TNC-220's, none have a problem with radio speaker feeds, so long as
you load the radio with say a 10r resistor, and that's more like keeping
the radio's speaker output chip bias point in the right place.
The "Non de-emphasised" audio examples are as expected very "bright" to
say the least.

I have added this to the TNCtest index page at:

just above the file download links.



The image file you download produces a MIXED MODE disk that combines
CD-ROM data and audio CD tracks. 

*	This is not a normal CD_ROM.
*	This is not a normal audio CD.
*	It is a combination of the two.  When you place this disk in a
computer CD drive, you will only see the CD-ROM data part of the disk.
The audio tracks will NOT show, and will NOT automatically start

Go to the Windows Start menu and do Start -- Programs -- Accessories --
Entertainment, and select the "CD Player" applet.  You will get an
on-screen display that looks like a car stereo CD player with start,
stop and track select buttons and a volume control.  Use this software
"device" to play the audio tracks. 

In a non-computer audio player such as a boombox or DiskMan (or a CD-ROM
drive being used stand-alone outside of a computer), the drive may
mistakenly see the first (data) track as a defective unplayable audio
track and do nothing. If so, use the track selector button to jump to
the next (first actual audio) track.


The de-emphasis on track 2 sounds muddier than most radios because the
de-emphasis in most radios doesn't conform to the official de-emphasis
curve.  Many radios don't even begin to roll off until 1K or higher
rather than starting at 300 Hz, in an effort to have "punchier" audio.
The recording reflects "worse case" de-emphasis roll-off .  

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.tapr.org/pipermail/aprssig/attachments/20061031/9d71abad/attachment.html>

More information about the aprssig mailing list