X-GM-THRID: 1203533621080903190 X-Gmail-Labels: rsgb lf X-Gmail-Received: 5f8b0b6ba37c927ea6d127b3c90915b4482a4868 Delivered-To: daveyxm@gmail.com Received: by 10.54.127.17 with SMTP id z17cs10983wrc; Mon, 5 Jun 2006 09:39:52 -0700 (PDT) Received: by 10.66.250.17 with SMTP id x17mr3550460ugh; Mon, 05 Jun 2006 09:39:52 -0700 (PDT) Return-Path: Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mx.gmail.com with ESMTP id u1si6358761uge.2006.06.05.09.39.51; Mon, 05 Jun 2006 09:39:52 -0700 (PDT) Received-SPF: neutral (gmail.com: 193.82.116.20 is neither permitted nor denied by best guess record for domain of owner-rsgb_lf_group@blacksheep.org) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1FnI2h-0001a9-HT for rs_out_1@blacksheep.org; Mon, 05 Jun 2006 17:35:03 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1FnI2h-0001a0-3Z for rsgb_lf_group@blacksheep.org; Mon, 05 Jun 2006 17:35:03 +0100 Received: from sj-iport-5.cisco.com ([171.68.10.87]) by relay1.thorcom.net with esmtp (Exim 4.62) (envelope-from ) id 1FnI2c-00076l-VW for rsgb_lf_group@blacksheep.org; Mon, 05 Jun 2006 17:35:03 +0100 Received: from sj-dkim-1.cisco.com ([171.71.179.21]) by sj-iport-5.cisco.com with ESMTP; 05 Jun 2006 09:32:41 -0700 X-IronPort-AV: i="4.05,211,1146466800"; d="scan'208,217"; a="288931227:sNHT6690978448" Received: from ams-core-1.cisco.com (ams-core-1.cisco.com [144.254.224.150]) by sj-dkim-1.cisco.com (8.12.11/8.12.11) with ESMTP id k55GWegC000503 for ; Mon, 5 Jun 2006 09:32:40 -0700 Received: from cisco.com (mrwint.cisco.com [64.103.71.48]) by ams-core-1.cisco.com (8.12.10/8.12.6) with ESMTP id k55GWdLf001354 for ; Mon, 5 Jun 2006 18:32:39 +0200 (MEST) Received: from [10.21.120.201] (sjc-vpn6-201.cisco.com [10.21.120.201]) by cisco.com (8.8.8-Cisco List Logging/8.8.8) with ESMTP id RAA26040 for ; Mon, 5 Jun 2006 17:32:38 +0100 (BST) Message-ID: <44845CA5.2000904@g3ysx.org.uk> Date: Mon, 05 Jun 2006 17:32:37 +0100 From: Stewart Bryant User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.2) Gecko/20040804 Netscape/7.2 (ax) X-Accept-Language: en-us, en MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: <003e01c678db$dc5cad70$0200a8c0@AUG2004> <44832B6D.3000805@g3ysx.org.uk> <44842AF4.2090802@verizon.net> In-Reply-To: <44842AF4.2090802@verizon.net> Authentication-Results: sj-dkim-1.cisco.com; header.From=stewart@g3ysx.org.uk; dkim=neutral X-Spam-Score: -0.6 (/) X-Spam-Report: autolearn=disabled,AWL=-0.704,HTML_40_50=0.086,HTML_MESSAGE=0.001,HTML_TITLE_EMPTY=0.045 Subject: Re: LF: Rb standard Content-Type: multipart/alternative; boundary="------------060402020207030709060104" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: * X-Spam-Status: No, hits=1.0 required=5.0 tests=HTML_20_30,HTML_MESSAGE, HTML_TITLE_EMPTY autolearn=no version=2.63 X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false Status: O X-Status: X-Keywords: X-UID: 5351 This is a multi-part message in MIME format. --------------060402020207030709060104 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Andre Kesteloot wrote: > Stewart Bryant wrote: > >> Walter Blanchard wrote: >> >>> A number of TAIT T801 frequency standards have just appeared on the >>> UK surplus market. >>> They're ex-cellphone bases and I understand have been ditched in >>> favour of GPS-locked standards. >> >> It's more likely that they are now getting their clock from the PSTN >> network. >> >> Stewart G3YSX >> > but don't they rely on GPS for geographical location of mobile > callers? In that case, would they use two separate time references ? Andre, They do not provide the US style exact location service over here. The only requirement on the EU systems is frequency. All of the providers that I have spoken to get this for free from the PSTN. When the network moves to VoIP via metro Ethernet that, as you can imagine, gives rise to a problem. GPS is unlikely to be the solution for many technical, economic and political reasons. Now it's possible that they are doing timing measurement, or some retiming because of a network jitter problem. It's also possible (and more likely) that these Rb systems are a relic of their analogue network (which did use free running oscillators) and which is being cleared out of the base stations to make room for next generation equipment. If that is the case, then there will be a lot of them, but they will all be quite old. - Stewart G3YSX --------------060402020207030709060104 Content-Type: text/html; charset=us-ascii Content-Transfer-Encoding: 7bit

Andre Kesteloot wrote:
Stewart Bryant wrote:
Walter Blanchard wrote:
A number of TAIT T801 frequency standards have just appeared on the UK surplus market.
They're ex-cellphone bases and I understand have been ditched in favour of GPS-locked standards.
It's more likely that they are now getting their clock from the PSTN network.

Stewart G3YSX
but don't they rely on GPS for geographical location of mobile callers? In that case, would they use two separate time references ?
Andre,

They do not provide the US style exact location service over here.

The only requirement on the EU systems is frequency. All of the providers that I have spoken
to get this for free from the PSTN. When the network moves to VoIP via metro Ethernet
that, as you can imagine, gives rise to a problem. GPS is unlikely to be the solution for
many technical, economic and political reasons.

Now it's possible that they are doing timing measurement, or some retiming because
of a network jitter problem.

It's also possible (and more likely) that these Rb systems are a relic of their analogue
network (which did use free running oscillators) and which is being  cleared out
of the base stations to make room for next generation equipment. If that is the case,
then there will be a lot of them, but they will all be quite old.

- Stewart G3YSX




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