[App_rpt-users] RTCM Parameter question

[Bill Hurlock]

Thanks. Where do I find the source kit at you mentioned?

Bill Hurlock

From: Jim Duuuude [mailto:telesistant at hotmail.com]
Sent: Tuesday, March 19, 2013 2:36 PM
To: Bill Hurlock; app_rpt mailing list
Subject: RE: [App_rpt-users] RTCM Parameter question

Unless you have a particularly quirky receiver, leave it at 0.

Quoting from the source kit (README-DSPBEW):

Baseband Examination Window



Typically, the discriminator of an FM communications receiver produces

results containing audio spectrum from the "sub-audible" range

(typically < 100 Hz) to well above frequencies able to be produced by

modulating audio. These higher frequencies can be utilized to determine

signal quality, since they can only contain noise (or no noise, if a

sufficiently strong signal is present).



For receivers (such as the Motorola Quantar, etc) that do not provide

sufficient spectral content at these "noise" frequencies (for various

reasons), The "DSP/BEW (Digital Signal Processor / Baseband Examination

Window)" feature of the RTCM firmware may be utilized.



These receivers are perfectly capable of providing valid "noise" signal

with no modulation on the input of the receiver, but with strong

modulation (high frequency audio and high deviation), it severely

interferes with proper analysis of signal strength.



This feature provides a means by which a "Window" of baseband (normal

audio range) signal is examined by a DSP and a determination of whether

or not sufficient audio is present to cause interference of proper

signal strength is made. During the VERY brief periods of time when it

is determined that sufficient audio is present to cause interference,

the signal strength value is "held" (the last valid value previous to

the time of interference) until such time that the interfering audio is

no longer present.



The DSP/BEW feature is selectable, and should not be used for a receiver

that does not need it.

> From: bill.hurlock at cpcomms.com<mailto:bill.hurlock at cpcomms.com>
> To: app_rpt-users at ohnosec.org<mailto:app_rpt-users at ohnosec.org>
> Date: Tue, 19 Mar 2013 18:21:50 +0000
> Subject: [App_rpt-users] RTCM Parameter question
>
> I can't seem to find any reference to what item 17 does in the RTCM setup menu. It says DSP/BEW and appears to have 2 choices 0 or 1.
>
> Bill Hurlock
> CPCommunications
> 856-234-1661 Home Office
> 856-264-1010 Cell
> 914-345-9292 Ext.429
> www.cpcomms.com<http://www.cpcomms.com>
> WA2TQI
>
> Providing Solutions for Audio and Video Communications
>
>
>
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