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[195.171.43.25]) by mx.google.com with ESMTP id he7si14965987wjc.26.2014.03.08.14.36.47 for ; Sat, 08 Mar 2014 14:36:47 -0800 (PST) Received-SPF: neutral (google.com: 195.171.43.25 is neither permitted nor denied by best guess record for domain of owner-rsgb_lf_group@blacksheep.org) client-ip=195.171.43.25; Authentication-Results: mx.google.com; spf=neutral (google.com: 195.171.43.25 is neither permitted nor denied by best guess record for domain of owner-rsgb_lf_group@blacksheep.org) smtp.mail=owner-rsgb_lf_group@blacksheep.org; dkim=pass header.i=@mx.aol.com Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1WMPUL-0008Kv-DA for rs_out_1@blacksheep.org; Sat, 08 Mar 2014 22:13:01 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1WMPUK-0008Km-ID for rsgb_lf_group@blacksheep.org; Sat, 08 Mar 2014 22:13:00 +0000 Received: from omr-m09.mx.aol.com ([64.12.143.82]) by relay1.thorcom.net with esmtps (TLSv1:DHE-RSA-AES256-SHA:256) (Exim 4.82) (envelope-from ) id 1WMPUI-0007Ma-1H for rsgb_lf_group@blacksheep.org; Sat, 08 Mar 2014 22:12:59 +0000 Received: from mtaout-mad02.mx.aol.com (mtaout-mad02.mx.aol.com [172.26.221.206]) by omr-m09.mx.aol.com (Outbound Mail Relay) with ESMTP id CCA37701ECBE1 for ; Sat, 8 Mar 2014 17:12:55 -0500 (EST) Received: from White (95-91-237-52-dynip.superkabel.de [95.91.237.52]) by mtaout-mad02.mx.aol.com (MUA/Third Party Client Interface) with ESMTPA id 0A8C438000083 for ; Sat, 8 Mar 2014 17:12:52 -0500 (EST) Message-ID: <4B1344E60A1E4FFDBCA08B382DA09B03@White> From: "Markus Vester" To: References: <2662DF5AA7FA416CBB09CDB90BBFF7B1@White> <016101cf39df$4f4c89a0$ede59ce0$@comcast.net> <01dc01cf3a3f$86997bb0$93cc7310$@comcast.net> <2FC5CAB271A6437CB35A5B100185CEDA@White> <025101cf3a52$e0925750$a1b705f0$@comcast.net> <7DB9DD5669FC4C648838510DCAC08AFB@White> <531A506E.9040103@abelian.org> <531A5C19.9060209@abelian.org> <02ba01cf3aa3$debaad50$9c3007f0$@comcast.net> <531AF126.2060600@abelian.org> <850A470A5B9F4483BED8B49D4791044A@White> <531B1D0C.3070208@abelian.org> <531B2478.70500@iup.uni-heidelberg.de> <531B796A.9000906@iup.uni-heidelberg.de> <6F39BC7EB5674C358E3C3AFFE8B7892D@White> <531B8AB1.5040700@iup.uni-heidelberg.de> Date: Sat, 8 Mar 2014 23:12:51 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal Importance: Normal X-Mailer: Microsoft Windows Live Mail 12.0.1606 X-MimeOLE: Produced By Microsoft MimeOLE V12.0.1606 x-aol-global-disposition: G DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mx.aol.com; s=20121107; t=1394316775; bh=kA7K7FNLWJX4QFCoCKrMPSdzeU0BxZLSsLwk7PdhPJk=; h=From:To:Subject:Message-ID:Date:MIME-Version:Content-Type; b=SgwjR844fctL8O5t2uVo1ltT4ufQ0NSttMntqn2d61l/Cj2PTXXSsLhgSCSHKmPBM 5pixlG8sIIjrGI1fQRo9u4ye2csBQHqc2wC/Wppg5q9e8Hjzur42EDBN7xh5rFfP6R I2Sp1Zu/Yeef+fAEFNVScNScY9M+MFHM/z8mhNuw= x-aol-sid: 3039ac1addce531b95e40152 X-AOL-IP: 95.91.237.52 X-Spam-Score: 0.0 (/) X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net", has identified this incoming email as possible spam. The original message has been attached to this so you can view it (if it isn't spam) or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: From: Stefan Schäfer Sent: Saturday, March 08, 2014 10:25 PM To: Re: LF: Microphone via WLAN (WiFi) ? Hi Markus, Am 08.03.2014 21:49, schrieb Markus Vester: Hi Stefan, [...] Content analysis details: (0.0 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at http://www.dnswl.org/, no trust [64.12.143.82 listed in list.dnswl.org] 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (markusvester[at]aol.com) -0.0 T_RP_MATCHES_RCVD Envelope sender domain matches handover relay domain -0.0 SPF_PASS SPF: sender matches SPF record 0.0 HTML_MESSAGE BODY: HTML included in message 0.0 T_DKIM_INVALID DKIM-Signature header exists but is not valid X-Scan-Signature: 9cafc73d135491d75f4f47d39ed43841 Subject: Re: LF: Microphone via WLAN (WiFi) ? Content-Type: multipart/alternative; boundary="----=_NextPart_000_000C_01CF3B23.ED8F9D60" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.6 required=5.0 tests=HTML_40_50,HTML_MESSAGE, MISSING_OUTLOOK_NAME 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 Dies ist eine mehrteilige Nachricht im MIME-Format. ------=_NextPart_000_000C_01CF3B23.ED8F9D60 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable From: Stefan Sch=E4fer=20 Sent: Saturday, March 08, 2014 10:25 PM To: rsgb_lf_group@blacksheep.org=20 Subject: Re: LF: Microphone via WLAN (WiFi) ? Hi Markus,=20 Am 08.03.2014 21:49, schrieb Markus Vester:=20 Hi Stefan, that one looks like an analog video system, 2.4 GHz FM, with a = dedicated receiver box. I once owned a similar set and attempted to = transfer 137 kHz directly through the video channel, without a mixer. = But with the strong in-band utility stations, the dynamic range seemed = too poor. How many dBs? - From memory, I'd say up some 45 dB demodulated video SNR, at least = when the TX was close to the RX. Scaled from 5 MHz to 1 Hz this sounds = quite high (112 dBHz), but in spite of some preemphasis the noise = density wasn't spread evenly across the video bandwidth. At the time I = didn't measure dynamic range properly, maybe I should take another look. = Today I'd be worried of 2.4 GHz colliding with other users, eg. my own = WLAN. On the other hand I'm not sure whether WLAN / WiFi standard would be = the best choice either when looking for low battery drain. What could be the alternative? It must not be a big project with special = parts, a project for experts. Ideally part 2 of the system, described in = my initial mail, should appear as a normal external USB soundcard to the = PC. But generally you know what i mean or thinking about?=20 There are cheap soundcards with 100 dB dynamic range, with some luck = even 120 dB (in 1 Hz).=20 - 100 dBHz is not difficult. At 48 ks/s this is just 56 dB in Nyquist = bandwidth, or 9 effective ADC bits. Cheap Bluetooth devices should be = able to get that far. It should also be achievable by a wide-FM link, = audio or video. They all run at USB, i.e. 5V, maybe even 3.3V is OK for the chip. And = also the WLAN chips, running at 5V, consuming just a few 10 mW. I also = saw cheap high gain WLAN directional antennas at amazon... - Maybe even a few 100 mW. Switching WLAN off in an Android device = significantly increased battery life.=20 I'm considering to start a request to the DARC, maybe DH5FFL, you know = him? He will at least know who's the man for such a project! Maybe = DF1TY, you know, from the CQDL ;-) 73, Stefan 73, Markus (DF6NM) From: Stefan Sch=E4fer=20 Sent: Saturday, March 08, 2014 9:11 PM To: rsgb_lf_group@blacksheep.org=20 Subject: Re: LF: Microphone via WLAN (WiFi) ? ... But now i found this:=20 = http://www.amazon.de/Kamera-%C3%9Cberwachungskamera-Empf%C3%A4nger-Zubeh%= C3%B6r-Wireless/dp/B004AZL6AE/ref=3Dpd_cp_ce_2 ... ------=_NextPart_000_000C_01CF3B23.ED8F9D60 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
 
From: Stefan Sch=E4fer =
Sent: Saturday, March 08, 2014 10:25 PM
Subject: Re: LF: Microphone via WLAN (WiFi) = ?

Hi = Markus,

Am=20 08.03.2014 21:49, schrieb Markus Vester:=20
Hi Stefan,
 
that one looks like an analog = video system,=20 2.4 GHz FM, with a dedicated receiver box. I once owned a similar set = and=20 attempted to transfer 137 kHz directly through the video channel, = without a=20 mixer. But with the strong in-band utility stations, the = dynamic=20 range seemed too poor.
How many dBs?
- From memory, I'd say = up some=20 45 dB demodulated video SNR, at least when the TX was close to the=20 RX. Scaled from 5 MHz to 1 Hz this sounds quite high (112 dBHz),=20 but in spite of some preemphasis the noise density wasn't spread = evenly=20 across the video bandwidth. At the time I didn't measure = dynamic range=20 properly, maybe I should take another look. Today I'd be worried of 2.4 = GHz=20 colliding with other users, eg. my own WLAN.
On the other hand I'm not sure = whether WLAN /=20 WiFi standard would be the best choice either when looking for low = battery=20 drain.
What could be the alternative? It must not be a big project with = special=20 parts, a project for experts. Ideally part 2 of the system, described in = my=20 initial mail, should appear as a normal external USB soundcard to the=20 PC.

But generally you know what i mean or thinking about? =

There=20 are cheap soundcards with 100 dB dynamic range, with some luck even 120 = dB (in 1=20 Hz).
 
- 100 dBHz is not difficult. At 48 ks/s = this is=20 just 56 dB in Nyquist bandwidth, or 9 effective ADC = bits. Cheap=20 Bluetooth devices should be able to get that far. It should also be = achievable by a wide-FM link, audio or video.
 
They all run at USB, i.e. 5V, maybe even 3.3V is OK for the chip. = And also=20 the WLAN chips, running at 5V, consuming just a few 10 mW. I also saw = cheap high=20 gain WLAN directional antennas at amazon...
- Maybe even a few 100 mW. Switching = WLAN=20 off in an Android device significantly increased battery life.=20

I'm considering to start a request to the DARC, = maybe=20 DH5FFL, you know him? He will at least know who's the man for such a = project!=20 Maybe DF1TY, you know, from the CQDL ;-)

73, Stefan
73,
Markus (DF6NM)

From: Stefan=20 Sch=E4fer
Sent: Saturday, March 08, 2014 9:11 PM
To: rsgb_lf_group@blacksheep.org
Subject: Re: LF: Microphone via WLAN (WiFi) = ?

...
But now i found this:
http://www.amazon.de/Kamera-%C3%9Cberwachungskam= era-Empf%C3%A4nger-Zubeh%C3%B6r-Wireless/dp/B004AZL6AE/ref=3Dpd_cp_ce_2

...
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