From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <tz2026@gmail.com>
Received: from mail-gy0-f171.google.com (mail-gy0-f171.google.com
	[209.85.160.171]) (using TLSv1 with cipher RC4-SHA (128/128 bits))
	(Client CN "smtp.gmail.com",
	Issuer "Google Internet Authority" (verified OK))
	by huchra.bufferbloat.net (Postfix) with ESMTPS id 2CCA520024C
	for <thumbgps-devel@lists.bufferbloat.net>;
	Mon, 12 Mar 2012 14:18:25 -0700 (PDT)
Received: by ghbz17 with SMTP id z17so4746887ghb.16
	for <thumbgps-devel@lists.bufferbloat.net>;
	Mon, 12 Mar 2012 14:18:24 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113;
	h=mime-version:sender:in-reply-to:references:from:date
	:x-google-sender-auth:message-id:subject:to:cc:content-type
	:content-transfer-encoding;
	bh=V4svhTlxYRYtgFq2+EBo8a28bu3/crQcsG2t4xSeIy4=;
	b=IAmev5qMwHzXK1Lo2Mp7BEcR+aHyNgHmB1cX+CZOhneiHLDpNut/3fHLVmNyrM98s+
	ZpRhOstwiTGfK2zAp4bg+afAf2K7ynnNSqvJe/0r6B52VgR44EU9FCMKMbFTvDxtE4me
	qzBmoVLUQVxQA+qt/2d7Qw4tNVKVYJtNw1llr0MnjrR7S+xPAmCovCExwMDAxznAk9vZ
	3S/7X8xT6iPPpyoyLgeGBfZENSIXxx7u7tOrbeV6N8jMmAaxflTO/O9Cqj0+I0NHjgAE
	yjYp68E8GYqC+oz9f+MTGInkZlbOuoIyfFH071+Hx+ffi84h9XiKS1voMv/WLM7NtrXW
	kmrQ==
Received: by 10.60.7.102 with SMTP id i6mr9266842oea.9.1331587104140; Mon, 12
	Mar 2012 14:18:24 -0700 (PDT)
MIME-Version: 1.0
Sender: tz2026@gmail.com
Received: by 10.182.68.164 with HTTP; Mon, 12 Mar 2012 14:18:04 -0700 (PDT)
In-Reply-To: <20120312210345.GC17357@thyrsus.com>
References: <CAPz3yKdBJZzhSVMrT514aPehJGXMHVnGNKgt5rYNM6EuQ7=MTg@mail.gmail.com>
	<20120312210345.GC17357@thyrsus.com>
From: tz <thomas@mich.com>
Date: Mon, 12 Mar 2012 17:18:04 -0400
X-Google-Sender-Auth: DfqeCDzmdRn_DFxxRJiy98HTfms
Message-ID: <CAFv7OigwG=YhXbg1Jek=nP=uLhxh4Xpt0gOjLowJY0sVjxZkOA@mail.gmail.com>
To: esr@thyrsus.com
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: quoted-printable
Cc: thumbgps-devel@lists.bufferbloat.net
Subject: Re: [Thumbgps-devel] Build vs. modify vs. what should we be doing
	anyway?
X-BeenThere: thumbgps-devel@lists.bufferbloat.net
X-Mailman-Version: 2.1.13
Precedence: list
List-Id: <thumbgps-devel.lists.bufferbloat.net>
List-Unsubscribe: <https://lists.bufferbloat.net/options/thumbgps-devel>,
	<mailto:thumbgps-devel-request@lists.bufferbloat.net?subject=unsubscribe>
List-Archive: <https://lists.bufferbloat.net/pipermail/thumbgps-devel>
List-Post: <mailto:thumbgps-devel@lists.bufferbloat.net>
List-Help: <mailto:thumbgps-devel-request@lists.bufferbloat.net?subject=help>
List-Subscribe: <https://lists.bufferbloat.net/listinfo/thumbgps-devel>,
	<mailto:thumbgps-devel-request@lists.bufferbloat.net?subject=subscribe>
X-List-Received-Date: Mon, 12 Mar 2012 21:18:25 -0000

On Mon, Mar 12, 2012 at 5:03 PM, Eric S. Raymond <esr@thyrsus.com> wrote:

> Reason #2 is that it's probably a single-layer board (can't think of
> any reason they'd have gone multilayer for a simple interconnect like
> this). =A0Which in turn means we may very well be able to
> reverse-engineer a workable PCB design and parts list just by looking
> at this thing.

The board is probably minimum 4 layer.

Every USB chip and every GPS chip I've seen in dongles are fine-pitch
surface mount.

You CANNOT do this with anything less than 2 layers with lots of vias,
and if the pitch is fine enough you will need at least 4.

Also the RF section for the GPS - antenna to the input - is critical.
You aren't just going to put some copper out there and have it work
well.

http://www.prolific.com.tw/eng/downloads.asp?ID=3D23

The prolific is 28 pin ssop with scattered power and ground pins.

GPS chips (except for highly integrated modules) are worse as far as
the pins you need to get to the right places.