Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on lipkowski.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, RCVD_IN_DNSWL_MED,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 X-Spam-DCC: EATSERVER: mailn 1166; Body=3 Fuz1=3 Fuz2=3 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by lipkowski.org (8.14.4/8.14.4/Debian-8+deb8u1) with ESMTP id v1QJWYwl009288 for ; Sun, 26 Feb 2017 20:32:35 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1ci4PO-0002eX-1y for rs_out_1@blacksheep.org; Sun, 26 Feb 2017 19:23:02 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1ci4PG-0002eO-Oo for rsgb_lf_group@blacksheep.org; Sun, 26 Feb 2017 19:22:54 +0000 Received: from lethe.lipkowski.org ([178.32.151.135] helo=lipkowski.org) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.87) (envelope-from ) id 1ci4PE-0006Vd-5w for rsgb_lf_group@blacksheep.org; Sun, 26 Feb 2017 19:22:53 +0000 Received: from mailn.lipkowski.org (localhost [127.0.0.1]) by lipkowski.org (8.14.4/8.14.4/Debian-8+deb8u1) with ESMTP id v1QJNDdV009257 (version=TLSv1/SSLv3 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT) for ; Sun, 26 Feb 2017 20:23:13 +0100 Received: from localhost (sq5bpf@localhost) by mailn.lipkowski.org (8.14.4/8.14.4/Submit) with ESMTP id v1QJNCWl009253 for ; Sun, 26 Feb 2017 20:23:13 +0100 X-Authentication-Warning: mailn.lipkowski.org: sq5bpf owned process doing -bs Date: Sun, 26 Feb 2017 20:23:12 +0100 (CET) From: Jacek Lipkowski To: rsgb_lf_group@blacksheep.org In-Reply-To: <3fe6768c-70d8-1832-7849-58f837ef3cff@psk31.plus.com> Message-ID: References: <58B29B10.6020906@posteo.de> <3fe6768c-70d8-1832-7849-58f837ef3cff@psk31.plus.com> User-Agent: Alpine 2.11 (DEB 23 2013-08-11) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.75 X-Scanned-By: MIMEDefang 2.75 on 10.1.3.10 X-Scan-Signature: e09cca6d8e44a91eadbdfb3e1b8aec09 Subject: Re: LF: ebnaut & speclab question Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed 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: 10723 On Sun, 26 Feb 2017, g3zjo wrote: > Many cheap GPS modules have an awful lot of jitter, not being designed for > accurate 1PPS timing applications. I tried several with SpecLab and was not > happy with the jitter performance. I have not tried one of the jittery ones > for EbNaut. i use a very cheap uBlox NEO-6M gps module. the 1pps pulse has been shortened to 1ms, and i haven't disabled SBAS (which should further help with jitter, but i forgot to do it). it works very well with vlfrx-tools (haven't looked at the code, but probably Paul included some magic code to average out jitter). i haven't measured it, but the vlf spectra have one sharp single peak on the tx frequency, even when i analyse a lot of data in very narrow bandwidth (such as 6h of data with 47uHz bins). these modules are about 11 euro on a local auction site, probably cheaper when ordered directly from china. i don't think you can get much cheaper than this VY 73 Jacek / SQ5BPF