[App_rpt-users] RTCM [RX Packet Out of Bounds] Updated

Fri Jun 1 00:19:24 UTC 2018

Hayden,

The time is in UTC, as reported by the RTCM.  The system time is typically a couple minutes off, but it wanders a bit.  Ergo, each time command 98 is executed, a different delta is reported.

I’m not aware of a full calibration routine, what are you referring to?

The GPS is connected at 9600 baud.

The RTCM’s have been modified to accept an external 9.6MHz reference, which is locked to GPS.

This is the relevant output from command 98:

Current Time: Fri  Jun 01, 2018  00:17:43.740

Last Rx Pkt System time: 06/01/2018 00:16:08.440, diff: 95300 msec

Last Rx Pkt Timestamp time: 06/01/2018 00:16:08.440, diff: 0 msec

Last Rx Pkt index: 160, inbounds: 1

Does “System Time” reference the time on the computer which apt_rpt executes?

Kindest Regards,

Kevin Babich | N9IAA

Valparaiso, IN 46383

From: App_rpt-users <app_rpt-users-bounces at lists.allstarlink.org> On Behalf Of Hayden Honeywood
Sent: Thursday, May 31, 2018 5:56 PM
To: app_rpt-users at lists.allstarlink.org
Subject: Re: [App_rpt-users] RTCM [RX Packet Out of Bounds] ***Updated***

Is the time in UTC? How far off is the system time?

Have you done a full calibration of each board?

What baud rate do you run on your GPS's?

I tend to use 9600 baud and have had no issues with the GPS's I have used.

There is various GPS debug tools available in the RTCM. They are documented here - 

https://wiki.allstarlink.org/wiki/RTCM_Client#GPS

Can you possibly try injecting a 9.6MHz signal in place of the crystal on board? Perhaps you have a variant of James KI0KN's problem where his crystals were off frequency.

I can't comment on that as I built all my boards and they have external frequency references.

Regards

Hayden VK7HH

From: App_rpt-users <app_rpt-users-bounces at lists.allstarlink.org <mailto:app_rpt-users-bounces at lists.allstarlink.org> > On Behalf Of Hayden Honeywood
Sent: Wednesday, May 30, 2018 5:34 PM
To: app_rpt-users at lists.allstarlink.org <mailto:app_rpt-users at lists.allstarlink.org> 
Subject: Re: [App_rpt-users] RTCM [RX Packet Out of Bounds] ***Updated***

What is your values in voter.conf for RX buffer (960) and in the RTCM client for TX buffer (480). Are all RTCM TX buffers set to the same value? Yes, 480.  These values were based upon the math Jim provided, which is a function of maximum latencies on the network.  We rarely have greater than 1ms to any host on the network.

Are all the GPS's in a location where they cannot be swamped with RF? Yes, and they utilize PCTEL antennas with filtering for use in RF dense environments.

Some users have had success with a dedicated RTCM as the master timing source (with no radio connected).   Has it been suspected that an RTCM doesn’t have the horsepower to handle both functions contemporaneously?

Regards

Hayden VK7HH

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Message: 3
Date: Wed, 30 May 2018 19:51:43 -0500
From: "Kevin Babich" <kevin.babich at gmail.com <mailto:kevin.babich at gmail.com> >
To: "'Users of Asterisk app_rpt'"
        <app_rpt-users at lists.allstarlink.org <mailto:app_rpt-users at lists.allstarlink.org> >
Subject: Re: [App_rpt-users] RTCM [RX Packet Out of Bounds]
        ***Updated***
Message-ID: <010001d3f879$8c2b3710$a481a530$@gmail.com <http://gmail.com> >
Content-Type: text/plain; charset="utf-8"

Hayden,

Do you know what exactly “RX Packet Out of Bounds” refers to?  I can infer its meaning, but, one can’t be certain.  Any thoughts why the system time is always so far off?  It has always been, since I began experimenting with the RTCM in 2012.  This is consistent across many RTCM’s.

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