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[195.171.43.25]) by mx.google.com with ESMTP id df2si13373229wjc.28.2014.03.18.16.50.56 for ; Tue, 18 Mar 2014 16:50:56 -0700 (PDT) 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 (test mode) header.i=@btinternet.com Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1WQ36c-0002dT-Qs for rs_out_1@blacksheep.org; Tue, 18 Mar 2014 23:07:34 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1WQ36b-0002dK-V1 for rsgb_lf_group@blacksheep.org; Tue, 18 Mar 2014 23:07:33 +0000 Received: from smtpout12.bt.lon5.cpcloud.co.uk ([65.20.0.132]) by relay1.thorcom.net with esmtp (Exim 4.82) (envelope-from ) id 1WQ36Z-0005Ry-8S for rsgb_lf_group@blacksheep.org; Tue, 18 Mar 2014 23:07:32 +0000 X-CTCH-RefID: str=0001.0A090205.5328D1B1.00D5,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0 X-Junkmail-Premium-Raw: score=12/97,refid=2.7.2:2014.3.18.194815:17:12.185,ip=,rules=__HAS_MSGID, __SANE_MSGID, MSGID_32HEX_LC, INVALID_MSGID_NO_FQDN, __MSGID_32HEX, __HAS_FROM, __PHISH_FROM2, __FRAUD_WEBMAIL_FROM, __TO_MALFORMED_2, __TO_NO_NAME, __BOUNCE_CHALLENGE_SUBJ, __BOUNCE_NDR_SUBJ_EXEMPT, __MIME_VERSION, __CT, __CTYPE_MULTIPART_ALT, __CTYPE_HAS_BOUNDARY, __CTYPE_MULTIPART, __HAS_X_PRIORITY, __HAS_MSMAIL_PRI, __HAS_X_MAILER, USER_AGENT_OE, __OUTLOOK_MUA_1, __USER_AGENT_MS_GENERIC, __ANY_URI, LINK_TO_IMAGE, __CP_URI_IN_BODY, __C230066_P5, __STOCK_PHRASE_7, __SUBJ_ALPHA_NEGATE, SUPERLONG_LINE, __HAS_HTML, BODY_SIZE_10000_PLUS, BODYTEXTH_SIZE_10000_LESS, __MIME_HTML, __TAG_EXISTS_HTML, __URI_NS, __PHISH_FROM, __OUTLOOK_MUA, __FRAUD_WEBMAIL, FORGED_MUA_OUTLOOK X-CTCH-Spam: Unknown Received: from gnat (81.129.181.41) by smtpout12.bt.lon5.cpcloud.co.uk (8.6.100.99.10223) (authenticated as alan.melia@btinternet.com) id 531857C50091DB2D for rsgb_lf_group@blacksheep.org; Tue, 18 Mar 2014 23:07:29 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=btinternet.com; s=btcpcloud; t=1395184051; bh=uYGa2Z0LkZdRfTh+UTVMj/KEdGUJrj9Qo5pgPenKofE=; h=Message-ID:From:To:References:Subject:Date:MIME-Version:Content-Type:X-Mailer; b=vjYSWZhHgIyK4T39UstIbBSGK/gl76du+zz8R25QWNS/ELSgN1G5PQ2icBOg2vAlS7ITUCgdOGPPUrjNCoJDh1WzRJgg43IL2M+MWKJ5De4lXHVEm7SpWokTgyVG26wQIohPej1X//eOx5LwPwy9CuTEZKGBbFke02VIrKPG4Wo= Message-ID: <296CC47933524F71B236C8479A87BEC8@gnat> From: "Alan Melia" To: References: <048001cf3c01$e513fd00$af3bf700$@comcast.net> <531DC2A6.4080606@iup.uni-heidelberg.de> <5328BF0B.6000308@iup.uni-heidelberg.de> Date: Tue, 18 Mar 2014 23:05:33 -0000 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5931 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.6157 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: Hi Stefan was there any problem with AGC on the MIC socket of the PC?? I doesnt seem to bea problem but I wondered if it explains your "strange effect". Thanks for sharing that was a very interesting evaluation. [...] 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 [65.20.0.132 listed in list.dnswl.org] 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: fe104f0109b1b9777bcb4182b547ef25 Subject: Re: LF: Bluetooth instead? Content-Type: multipart/alternative; boundary="----=_NextPart_000_0022_01CF42FE.90AE1D50" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: * X-Spam-Status: No, hits=1.6 required=5.0 tests=FORGED_MUA_OUTLOOK, HTML_MESSAGE 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 This is a multi-part message in MIME format. ------=_NextPart_000_0022_01CF42FE.90AE1D50 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hi Stefan was there any problem with AGC on the MIC socket of the PC?? I = doesnt seem to bea problem but I wondered if it explains your "strange = effect". Thanks for sharing that was a very interesting evaluation. Alan G3NYK ----- Original Message -----=20 From: Stefan Sch=E4fer=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Tuesday, March 18, 2014 9:47 PM Subject: Re: LF: Bluetooth instead? Hi all,=20 I'm continuing with my report about experiments with a wireless AF = bluetooth bridge that will (hopefully) allow to transfer a VLF or LF/MF = spectrum between antenna and receiver. Meanwhile i bought 2 RTX1 units = (http://www.amazon.de/B-Speech-Stereo-Bluetooth-Receiver-Transmitter/dp/B= 00CB3KGYE/ref=3Dsr_1_1?ie=3DUTF8&qid=3D1394458092&sr=3D8-1&keywords=3DB-S= peech+RTX1+Stereo+Bluetooth+Receiver+und+Transmitter) One is used as the TX and the other one for the RX. It is a stand = alone system, actually the PC does not notice anything from the = bluetooth stuff. That means, no software or driver or firmware and all = that stuff is needed, just these 2 small devices. Now, measurements: The measurements were done with SpecLab and the RX connected to the = MIC input of the PC where SpecLab is running. Noisefloor: -100 dBHz, sometimes popping up to -90 dBHz. Dynamic range (tested with a single sine tone at 1500 Hz, between = Intermod and "O-copy"): 66 dB Dynamic range (tested with a single sine tone at 10000 Hz, between = Intermod and "O-copy"): 45 dB (distortion acceptable) High cutoff frequency: ~ 20 kHz Low cutoff frequency: ~ 20 Hz Power consumption of the transmitter at 5 V DC (mini-USB) (including = the red LEDs indicating a connection to the receiver): 59 mA (~0.3 W) Spectrum distortion / frequency response: I've replayed a VLF = recording for that test, including sferics, MSK stations, the Alphas... = Left is original, right is passed though the 2x RTX1 system = https://dl.dropboxusercontent.com/u/19882028/VLF/L%3Doriginal_R%3Dpassedt= hroughRTX1.png White noise frequency response:=20 = https://dl.dropboxusercontent.com/u/19882028/VLF/white%20noise%20test%20R= TX1%20left%20in%20right%20out.png Strange effects: When suddenly removing the noise input, the output = just slowly return to the background noise of the system. This can't be = good for QRN!! https://dl.dropboxusercontent.com/u/19882028/VLF/Rauschsprung.png There can more QRM traces when the USB power supply is used on the RX. = A traditional transformer power supply or a battery improves the = situation. However this is not critical above 3 kHz. Conclusion: NOT suitable for our purposes! :-( I'll send them back... ...and i'll spend more time to learn what i have to choose and how to = configure, maybe even homemade SMD ICs allowing to transfer much more = bandwith without A2DC codecs and such a stuff. 73, Stefan/DK7FC Am 10.03.2014 14:48, schrieb Stefan Sch=E4fer:=20 Hi all,=20 I want to share my recent results of experiments trying to arrange a = wireless AF connection, which can be used for a VLF antenna or any other = RF spectrum such as 630m and 2200m bands. The goal is always to decouple = local QRM sources from a RX antenna installed in a quiet(er) location, = to improve the RX capability of the amateur radio station in noisy = environments.=20 It looks like there are some cheap and useful devices on the market, = using bluetooth technique. Last night i did some first tests!=20 First i simply wanted to transfer music from my smartphone to my = netbook, using the bluetooth function (never used that before). This = worked very well in the first attempt! There was no audible sound = quality loss. The sound was played on the speaker of the netbook. But, = more precise, it is not the speaker but the standard audio device! :-) = That means, you can define virtual audio cable 1 as the standard output = device! And here we are, we can feed the audio signal to SpecLab, = without additional software except VAC which runs on many LF/MF/VLF PCs = anyway. This allowed me to watch the spectrum and see if the signal is = distorted or drifting or anything else. Again there was no audible and = visible indication of a significant quality loss.=20 Next i wanted to get an impression about the possible dynamic range = of this wireless bridge. I uploaded a VLF recording (the original one = from 4X1RF, including my 8970 Hz signal :-) ) as a wav file to the = smartphone and played it via the bluetooth link. The signal level in = this recording is quite low and depends on the volume setting of the = smartphone. Here i saw that the background noise of the system, i.e. the = dynamic range, is 120 dB, with some noise lines/peaks peaking to -100 = dB. This looked very fine! Also the full 0...24 kHz spectrum was = transferred via the bluetooth link and it was possible to lock SpecLab = to DHO38 which was included in the recording! Next, this allowed me to = watch the frequency drift of the system. Looks quite normal for a = crystal, i.e. useful for our purposes.=20 Now i want to try bluetooth for VLF and LF reception and i want to = do some distance tests. 2 km distance, using a directional antenna, this = would be very fine.=20 At amazon, there are relatively cheap bluetooth transmitters with an = external antenna, e.g. = http://www.amazon.de/B-Speech-Stereo-Bluetooth-Receiver-Transmitter/dp/B0= 0CB3KGYE/ref=3Dsr_1_1?ie=3DUTF8&qid=3D1394458092&sr=3D8-1&keywords=3DB-Sp= eech+RTX1+Stereo+Bluetooth+Receiver+und+Transmitter=20 These do even have an external antenna and will allow to use a high = gain antenna for higher distances and help to avoid collisions with = other signal sources. Since my netbook has an internal bluetooth adapter = and since i now know that the received signal can be fed to SpecLab, it = is worth to buy the transmitter and to do further tests. This one seems = to be one of the stronger versions with 100 mW RF power. Hopefully the = power consumption is acceptable...=20 I will report about the progress...=20 73, Stefan/DK7FC=20 ------=_NextPart_000_0022_01CF42FE.90AE1D50 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Hi Stefan was there any problem with = AGC on the MIC=20 socket of the PC?? I doesnt seem to bea problem but I wondered if it = explains=20 your "strange effect".
 
Thanks for sharing that was a very = interesting=20 evaluation.
 
Alan G3NYK
----- Original Message -----
From:=20 Stefan Sch=E4fer =
Sent: Tuesday, March 18, 2014 = 9:47=20 PM
Subject: Re: LF: Bluetooth = instead?

Hi all,

I'm continuing with my report about = experiments=20 with a wireless AF bluetooth bridge that will (hopefully) allow to = transfer a=20 VLF or LF/MF spectrum between antenna and receiver.

Meanwhile i = bought=20 2 RTX1 units (= http://www.amazon.de/B-Speech-Stereo-Bluetooth-Receiver-Transmitter/dp/B0= 0CB3KGYE/ref=3Dsr_1_1?ie=3DUTF8&qid=3D1394458092&sr=3D8-1&key= words=3DB-Speech+RTX1+Stereo+Bluetooth+Receiver+und+Transmitter)
<= BR>One=20 is used as the TX and the other one for the RX. It is a stand alone = system,=20 actually the PC does not notice anything from the bluetooth stuff. = That means,=20 no software or driver or firmware and all that stuff is needed, just = these 2=20 small devices.

Now, measurements:
The measurements were done = with=20 SpecLab and the RX connected to the MIC input of the PC where SpecLab = is=20 running.

Noisefloor: -100 dBHz, sometimes popping up to = -90=20 dBHz.
Dynamic range (tested with a single sine tone at 1500 = Hz,=20 between Intermod and "O-copy"): 66 dB
Dynamic range (tested = with a=20 single sine tone at 10000 Hz, between Intermod and "O-copy"): 45 dB=20 (distortion acceptable)
High cutoff frequency: ~ 20 = kHz
Low=20 cutoff frequency: ~ 20 Hz
Power consumption of the = transmitter=20 at 5 V DC (mini-USB) (including the red LEDs indicating a = connection to=20 the receiver): 59 mA (~0.3 W)

Spectrum distortion / = frequency=20 response: I've replayed a VLF recording for that test, including = sferics,=20 MSK stations, the Alphas... Left is original, right is passed though = the 2x=20 RTX1 system
https://dl.dropboxusercontent.com/u/19882028/VLF/= L%3Doriginal_R%3DpassedthroughRTX1.png

White=20 noise frequency response:
https://dl.dropboxusercontent.= com/u/19882028/VLF/white%20noise%20test%20RTX1%20left%20in%20right%20out.= png

Strange=20 effects: When suddenly removing the noise input, the output just = slowly=20 return to the background noise of the system. This can't be good for=20 QRN!!
https://dl.dropboxusercontent.com/u/19882028/VLF/Rauschsprung.png

There=20 can more QRM traces when the USB power supply is used on the RX. A = traditional=20 transformer power supply or a battery improves the situation. However = this is=20 not critical above 3 kHz.

Conclusion:
NOT suitable = for our=20 purposes! :-( I'll send them back...

...and i'll spend more = time to=20 learn what i have to choose and how to configure, maybe even homemade = SMD ICs=20 allowing to transfer much more bandwith without A2DC codecs and such a = stuff.

73, Stefan/DK7FC


Am 10.03.2014 14:48, schrieb = Stefan=20 Sch=E4fer:=20
Hi=20 all,

I want to share my recent results of experiments trying = to=20 arrange a wireless AF connection, which can be used for a VLF = antenna or any=20 other RF spectrum such as 630m and 2200m bands. The goal is always = to=20 decouple local QRM sources from a RX antenna installed in a = quiet(er)=20 location, to improve the RX capability of the amateur radio station = in noisy=20 environments.

It looks like there are some cheap and useful = devices=20 on the market, using bluetooth technique. Last night i did some = first tests!=20

First i simply wanted to transfer music from my smartphone = to my=20 netbook, using the bluetooth function (never used that before). This = worked=20 very well in the first attempt! There was no audible sound quality = loss. The=20 sound was played on the speaker of the netbook. But, more precise, = it is not=20 the speaker but the standard audio device! :-) That means, you can = define=20 virtual audio cable 1 as the standard output device! And here we = are, we can=20 feed the audio signal to SpecLab, without additional software except = VAC=20 which runs on many LF/MF/VLF PCs anyway. This allowed me to watch = the=20 spectrum and see if the signal is distorted or drifting or anything = else.=20 Again there was no audible and visible indication of a significant = quality=20 loss.

Next i wanted to get an impression about the possible = dynamic=20 range of this wireless bridge. I uploaded a VLF recording (the = original one=20 from 4X1RF, including my 8970 Hz signal :-) ) as a wav file to the=20 smartphone and played it via the bluetooth link. The signal level in = this=20 recording is quite low and depends on the volume setting of the = smartphone.=20 Here i saw that the background noise of the system, i.e. the dynamic = range,=20 is 120 dB, with some noise lines/peaks peaking to -100 dB. This = looked very=20 fine! Also the full 0...24 kHz spectrum was transferred via the = bluetooth=20 link and it was possible to lock SpecLab to DHO38 which was included = in the=20 recording! Next, this allowed me to watch the frequency drift of the = system.=20 Looks quite normal for a crystal, i.e. useful for our purposes. =

Now=20 i want to try bluetooth for VLF and LF reception and i want to do = some=20 distance tests. 2 km distance, using a directional antenna, this = would be=20 very fine.

At amazon, there are relatively cheap bluetooth=20 transmitters with an external antenna, e.g. = http://www.amazon.de/B-Speech-Stereo-Bluetooth-Receiver-Transmitter/dp/B0= 0CB3KGYE/ref=3Dsr_1_1?ie=3DUTF8&qid=3D1394458092&sr=3D8-1&key= words=3DB-Speech+RTX1+Stereo+Bluetooth+Receiver+und+Transmitter=20

These do even have an external antenna and will allow to use = a high=20 gain antenna for higher distances and help to avoid collisions with = other=20 signal sources. Since my netbook has an internal bluetooth adapter = and since=20 i now know that the received signal can be fed to SpecLab, it is = worth to=20 buy the transmitter and to do further tests. This one seems to be = one of the=20 stronger versions with 100 mW RF power. Hopefully the power = consumption is=20 acceptable...

I will report about the progress... =

73,=20 Stefan/DK7FC =



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