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[195.171.43.25]) by mx.google.com with ESMTP id l7si20074648eey.60.2013.07.09.04.37.53 for ; Tue, 09 Jul 2013 04:37:54 -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=@comcast.net Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1UwVvf-0003F6-Jw for rs_out_1@blacksheep.org; Tue, 09 Jul 2013 12:17:55 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1UwVve-0003Ex-R7 for rsgb_lf_group@blacksheep.org; Tue, 09 Jul 2013 12:17:54 +0100 Received: from qmta11.westchester.pa.mail.comcast.net ([76.96.59.211]) by relay1.thorcom.net with esmtp (Exim 4.77) (envelope-from ) id 1UwVvb-00013J-W2 for rsgb_lf_group@blacksheep.org; Tue, 09 Jul 2013 12:17:53 +0100 Received: from omta06.westchester.pa.mail.comcast.net ([76.96.62.51]) by QMTA11.westchester.pa.mail.comcast.net with comcast id yB6b1l00316LCl05BBHpwQ; Tue, 09 Jul 2013 11:17:49 +0000 Received: from JAYDELL ([71.234.119.9]) by omta06.westchester.pa.mail.comcast.net with comcast id yBHo1l01C0CFS1j3SBHp24; Tue, 09 Jul 2013 11:17:49 +0000 Message-ID: <001601ce7c95$f235b360$6401a8c0@JAYDELL> From: To: References: <51D498BD.3050007@iup.uni-heidelberg.de> <005b01ce798a$b0476600$6d01a8c0@DELL4> <20130706131640.GG5246@cs.utwente.nl> <7D6B8CBB38964C9C82487F5D0F3648FC@FMVXD1232> <20130707203537.GA30691@cs.utwente.nl> <51DA00C8.6000600@iup.uni-heidelberg.de> <51DA0212.8020808@iup.uni-heidelberg.de> <51DA03CE.6020508@iup.uni-heidelberg.de> <51DA1680.6030602@iup.uni-heidelberg.de> <51DB6CB3.2080708@iup.uni-heidelberg.de> Date: Tue, 9 Jul 2013 07:17:48 -0400 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2180 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=comcast.net; s=q20121106; t=1373368669; bh=bVub5w/h2xPwRSw2MOQCib/rcNNaU83VCiR9poPEzY4=; h=Received:Received:Message-ID:From:To:Subject:Date:MIME-Version: Content-Type; b=BxNs0APVWL+COomUstTB1dACPzv3zre/jGyL37FHIgUuv/gskEhNyO+kOtlyivtBo E9mM4f+lHBsrVpmhsahdai+1+bchMZfJuFRZYjkySZ401YEoR63d0Eax/SmToSwG1x r1UdF1wmmwTuPGP9A8mSTxusthCCc2n+RscxZcVQvKm0WjrRl5smm/+A/7347vyomV E1podfeYAebIQRS8r4eQA58UNtWSIOoKyiKOABEbnvbc3iluCnA1c4fa/13+f3AW7F 8Mzxs3WzCyXq0tZplVqx5WBBghOAkpgV+Hxeb5c2elqamG1RQvA1k/KteXfh49cjw+ iPxPzkKiynWXg== X-Spam-Score: 1.4 (+) 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: Stefan Suggestion ... in the interest of better dipole balance mount battery so that it isn't taped to one half of the dipole. Suspect it's quite easy to upset the balance on such a short antenna. Jay W1VD WD2XNS WE2XGR/2 ----- Original Message ----- From: Stefan Schäfer To: Monday, July 08, 2013 9:51 PM Subject: Re: LF: Re: MiniWhip antenna, fiber optic [...] Content analysis details: (1.4 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at http://www.dnswl.org/, no trust [76.96.59.211 listed in list.dnswl.org] 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (jrusgrove[at]comcast.net) -0.0 SPF_PASS SPF: sender matches SPF record -0.3 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain 0.0 HTML_MESSAGE BODY: HTML included in message 0.0 T_DKIM_INVALID DKIM-Signature header exists but is not valid 1.7 AXB_XMAILER_MIMEOLE_OL_4379D AXB_XMAILER_MIMEOLE_OL_4379D X-Scan-Signature: 80e63e173fa93b7854d61e1697120204 Subject: Re: LF: Re: MiniWhip antenna, fiber optic Content-Type: multipart/alternative; boundary="----=_NextPart_000_0012_01CE7C74.6AB8CE70" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.8 required=5.0 tests=HTML_20_30,HTML_MESSAGE, NO_REAL_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 Status: O X-Status: X-Keywords: X-UID: 2821 This is a multi-part message in MIME format. ------=_NextPart_000_0012_01CE7C74.6AB8CE70 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit Stefan Suggestion ... in the interest of better dipole balance mount battery so that it isn't taped to one half of the dipole. Suspect it's quite easy to upset the balance on such a short antenna. Jay W1VD WD2XNS WE2XGR/2 ----- Original Message ----- From: Stefan Schäfer To: rsgb_lf_group@blacksheep.org Sent: Monday, July 08, 2013 9:51 PM Subject: Re: LF: Re: MiniWhip antenna, fiber optic Hi all, Today i just made some changes on the antenna. Now the dipole legs are aluminium foil on a plastic tube. Length is 30 cm (29cm on the side where the battery is connected, GND of the circuit) and diameter is 18mm. The forward current of the TX LED is about 15 mA. Some working point optimisations were done so the gain is a bit higher (not only due to the increased electrode capacity). I know, the signal voltage does NOT rise linearly with the capacity of the electrodes (thinking about the voltage between 2 parallel plates of a capacitor which is put in an external electrical field) but it allows to realise a RC lowpassfilter in a next step. New antenna: https://dl.dropboxusercontent.com/u/19882028/LF/20130709_033824.jpg I can now do some /p experiments in the far field (for my local 630m transmissions) in a location without trees, houses.... 73, Stefan/DK7FC Am 08.07.2013 03:31, schrieb Stefan Schäfer: Hi all, Well, somehow i didn't want to stop, so i now built the RX too: https://dl.dropboxusercontent.com/u/19882028/LF/DK7FC_fiber%20optic%20active%20dipole_RX.jpg I made some changes in the RX schematic, using a J310 instead of the BF862 but the principle schematic is the same. The working points look as expected. BTW that electrical/optic/electrical converter must be quite wide in the transferred frequency range, i guess starting from a few 100 Hz to a few 100 kHz. When connecting the BNC output to the scope, the noise shown from the scope does not change. When switching on the active probe there is some noise visible in the range of 2 ms/div. The probe stands in the lab where many noise sources can be expected. And suddenly!!! : It was 1:06 UTC. I am transmitting WSPR-2 each 6 minutes on 630m, from the same building, in some 10m distance. Suddenly there was a 472 kHz signal on the scope, although the antenna can't work :-) The short dipole is completely floating. See another photo where the floating antenna is placed on a (isolating and low coupling capacity to sourroundings) cardboard: https://dl.dropboxusercontent.com/u/19882028/LF/Signal%21.jpg When switching off the active antenna, the signal disappears completely on the scope, of course! When coming closer with my hand to one of the legs of the dipole or the battery, the signal rises, as expected. I think we can agree that this antenna IS floating!! So far for now. It's 3:26 AM and i think i should take some sleep :-) Looking forward to the tomorrows experiments. Let me know if you have suggestions for experiments! 73, GN, Stefan/DK7FC Am 08.07.2013 02:11, schrieb Stefan Schäfer: 3rd: https://dl.dropboxusercontent.com/u/19882028/LF/DK7FC_fiber%20optic%20active%20dipole_TX3.jpg The optic cable is 9m long. Am 08.07.2013 02:04, schrieb Stefan Schäfer: another image of the TX: https://dl.dropboxusercontent.com/u/19882028/LF/DK7FC_fiber%20optic%20active%20dipole_TX2.jpg Am 08.07.2013 01:59, schrieb Stefan Schäfer: Hi all, OK, although it can't work (do you remember?!) i built an active antenna with battery supply and fiber optic output. The active part is a BF862. The circuit is quite simple: https://dl.dropboxusercontent.com/u/19882028/LF/DK7FC_fiber%20optic%20active%20dipole%20schematic.jpg It is a first idea for the schematic. Maybe i will change it later so that the gate is shifted to 9V/2. Just for first experiments. In various tests with the BF862 i found that it was necessary to add a ferrite bead directly in front of the gate to prevent VHF oscillations of the JFET. The TX is already working: https://dl.dropboxusercontent.com/u/19882028/LF/DK7FC_fiber%20optic%20active%20dipole_TX.jpg Yes yes yes, it is not truely symmetric and the capacity at source must be a bit larger than that of the leg connected to gate. Anyway it will be useful for some basic and interesting experiments. RX is ready tomorrow. 73, Stefan/DK7FC ------=_NextPart_000_0012_01CE7C74.6AB8CE70 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable =EF=BB=BF
Stefan
 
Suggestion ... in the interest of = better dipole=20 balance mount battery so that it isn't taped to one half of the = dipole.=20 Suspect it's quite easy to upset the balance on such a short=20 antenna.
 
Jay W1VD  WD2XNS =20 WE2XGR/2 
----- Original Message -----
From:=20 Stefan = Sch=C3=A4fer
Sent: Monday, July 08, 2013 = 9:51 PM
Subject: Re: LF: Re: MiniWhip = antenna,=20 fiber optic

Hi all,

Today i just made some changes on the = antenna.=20 Now the dipole legs are aluminium foil on a plastic tube. Length is 30 = cm=20 (29cm on the side where the battery is connected, GND of the circuit) = and=20 diameter is 18mm. The forward current of the TX LED is about 15 mA. = Some=20 working point optimisations were done so the gain is a bit higher (not = only=20 due to the increased electrode capacity). I know, the signal voltage = does NOT=20 rise linearly with the capacity of the electrodes (thinking about the = voltage=20 between 2 parallel plates of a capacitor which is put in an external=20 electrical field) but it allows to realise a RC lowpassfilter in a = next=20 step.
New antenna: https://dl.dropboxusercontent.com/u/19882028/LF/20130709_033824.jpg
I=20 can now do some /p experiments in the far field (for my local 630m=20 transmissions) in a location without trees, houses....

73,=20 Stefan/DK7FC


Am 08.07.2013 03:31, schrieb Stefan = Sch=C3=A4fer:=20
Hi=20 all,

Well, somehow i didn't want to stop, so i now built the = RX too:=20 https://dl.dropboxusercontent.com/u/19882028/LF/= DK7FC_fiber%20optic%20active%20dipole_RX.jpg=20 I made some changes in the RX schematic, using a J310 instead of the = BF862=20 but the principle schematic is the same. The working points look as=20 expected. BTW that electrical/optic/electrical converter must be = quite wide=20 in the transferred frequency range, i guess starting from a few 100 = Hz to a=20 few 100 kHz.

When connecting the BNC output to the scope, the = noise=20 shown from the scope does not change. When switching on the active = probe=20 there is some noise visible in the range of 2 ms/div. The probe = stands in=20 the lab where many noise sources can be expected.

And = suddenly!!! :=20 It was 1:06 UTC. I am transmitting WSPR-2 each 6 minutes on 630m, = from the=20 same building, in some 10m distance. Suddenly there was a 472 kHz = signal=20 on the scope, although the antenna can't work :-) The short = dipole is=20 completely floating. See another photo where the floating antenna is = placed=20 on a (isolating and low coupling capacity to sourroundings) = cardboard: https://dl.dropboxusercontent.com/u/19882028/LF/= Signal%21.jpg

When=20 switching off the active antenna, the signal disappears completely = on the=20 scope, of course!

When coming closer with my hand to one of = the legs=20 of the dipole or the battery, the signal rises, as expected. I think = we can=20 agree that this antenna IS floating!!

So far for now. It's = 3:26 AM=20 and i think i should take some sleep :-) Looking forward to the = tomorrows=20 experiments. Let me know if you have suggestions for = experiments!

73,=20 GN, Stefan/DK7FC


Am 08.07.2013 02:11, schrieb Stefan = Sch=C3=A4fer:=20
3rd: https://dl.dropboxusercontent.com/u/19882028/LF/= DK7FC_fiber%20optic%20active%20dipole_TX3.jpg

The=20 optic cable is 9m long.

Am 08.07.2013 02:04, schrieb Stefan = Sch=C3=A4fer:=20
another image of the TX: https://dl.dropboxusercontent.com/u/19882028/LF/= DK7FC_fiber%20optic%20active%20dipole_TX2.jpg

Am=20 08.07.2013 01:59, schrieb Stefan Sch=C3=A4fer:=20
Hi all,

OK, although it can't work (do = you=20 remember?!) i built an active antenna with battery supply and = fiber=20 optic output. The active part is a BF862. The circuit is quite = simple: https://dl.dropboxusercontent.com/u/19882028/LF/= DK7FC_fiber%20optic%20active%20dipole%20schematic.jpg=20 It is a first idea for the schematic. Maybe i will change it = later so=20 that the gate is shifted to 9V/2. Just for first experiments. = In=20 various tests with the BF862 i found that it was necessary to = add a=20 ferrite bead directly in front of the gate to prevent VHF = oscillations=20 of the JFET.

The TX is already working: https://dl.dropboxusercontent.com/u/19882028/LF/= DK7FC_fiber%20optic%20active%20dipole_TX.jpg
Yes=20 yes yes, it is not truely symmetric and the capacity at source = must be=20 a bit larger than that of the leg connected to gate. Anyway it = will be=20 useful for some basic and interesting experiments.

RX = is ready=20 tomorrow.

73,=20 = Stefan/DK7FC
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