Article 36497 of sci.geo.satellite-nav:
Path: matra.meer.net!pixie.mcom.com!news.Stanford.EDU!su-news-hub1.bbnplanet.com!cpk-news-hub1.bbnplanet.com!news.bbnplanet.com!news-peer.sprintlink.net!news.sprintlink.net!sprint!newsjunkie.ans.net!newsfeeds.ans.net!interserv.etn.com!usenet
From: thfborn@t-online.de (Thomas Born)
Newsgroups: sci.geo.satellite-nav
Subject: *** Garmin WARNING *** DO NOT ATTEMPT TO LOCK ONTO LIVE SATELLITES WHILE IN THE TEST MODE!
Date: Mon, 14 Apr 1997 20:38:21 GMT
Organization: Private Site
Lines: 78
Message-ID: <3352937c.9223458@news.etn.com>
Reply-To: thfborn@t-online.de
NNTP-Posting-Host: firewall.etn.com
Mime-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 8bit
X-Newsreader: Forte Agent 1.0/32.390
Xref: matra.meer.net sci.geo.satellite-nav:36497

Please read THIS. It's the ORINIGNAL, what my friend SPY has
found in his mailbox.

Since I'm the host of the 'secrets-page', I must post this.

---  email from Garmin Product Support ---

Rob,

I saw your site concerning the test functions of the 12 XL and I
was quite impressed. You must have a lot of time on your hands.
I quess I will never understand the facination with the test
page of the unit.

The data displayed on this page is utilized for testing the
unit in a factory environment when connected to a very precise
signal generator.

With this page we can measure the receivers ambient noise level,
signal response with a given stimulus, SNR (gotta have a signal
for this one too) and internal oscillator drift. The unit uses
a software compensated crystal oscillator (SCXO) as the internal
reference oscillator. The SCXO is initially set at the factory,
and then "learns" as it is used and experiences new temperatures,
and crystal aging. In this fashion the unit never needs to be
re-calibrated.

In normal mode, the unit will account for doppler shift from the
satellites and only re-calibrate it's SCXO when locked on having
the time variable "nailed down". In TEST mode however, the unit
assumes a perfect satellite signal with NO DOPPLER, and will
re-calibrate it's SCXO to the raw carrier received if it locks
onto the satellite it is expecting. (No, I won't tell you which
one).

*** WARNING ***

         DO NOT ATTEMPT TO LOCK ONTO LIVE SATELLITES
         WHILE IN THE TEST MODE!

You are asking people to destroy the SCXO compensation curve in
their units, which may render them useless. I doubt that you will
receive favorable responses from folks whom you have instructed to
disable their units, nor will we be pleased to have to reset and
re-calibrate these units, or worse yet, take them back as
defective exchanges when there was nothing wrong with them until
they followed your suggestion.

Our Engineering team has been considering removing the TEST
functions from the units and only allow access to this data with
special instrumentation.

I suspect that when some of them read your posts and see your
site, that will seal their decision.

I understand and appreciate curiosity, If you want to disable your
unit, that is your decision. PLEASE do not ask people around the
world to do the same when they are not aware of the consequences.
 
Thank you and best regards,

Bill Stone
Product Suppport Manager
 
GARMIN International
1200 E. 151st Street
Olathe, KS 66062 USA
 
tel. 800/800.1020
913/397.8200
fax. 913/397.0836

--- /email from Garmin Product Support ---

No more words to say :-(((((((((

  Thomas