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[195.171.43.25]) by mx.google.com with ESMTP id w9si19801622wja.19.2013.07.25.16.25.50 for ; Thu, 25 Jul 2013 16:25:51 -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 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1V2U2G-0002fd-PZ for rs_out_1@blacksheep.org; Thu, 25 Jul 2013 23:29:24 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1V2U2G-0002fU-4z for rsgb_lf_group@blacksheep.org; Thu, 25 Jul 2013 23:29:24 +0100 Received: from relay.uni-heidelberg.de ([129.206.100.212]) by relay1.thorcom.net with esmtps (TLSv1:AES256-SHA:256) (Exim 4.77) (envelope-from ) id 1V2U2D-00079F-Mp for rsgb_lf_group@blacksheep.org; Thu, 25 Jul 2013 23:29:23 +0100 Received: from freitag.iup.uni-heidelberg.de (freitag.iup.uni-heidelberg.de [129.206.29.204]) by relay.uni-heidelberg.de (8.14.1/8.14.1) with ESMTP id r6PMTKM5013568 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Fri, 26 Jul 2013 00:29:21 +0200 Received: from [129.206.22.206] (pc206.iup.uni-heidelberg.de [129.206.22.206]) by freitag.iup.uni-heidelberg.de (8.12.11.20060308/8.11.2) with ESMTP id r6PMTK8k012364 for ; Fri, 26 Jul 2013 00:29:20 +0200 Message-ID: <51F1A6BB.6070805@iup.uni-heidelberg.de> Date: Fri, 26 Jul 2013 00:29:15 +0200 From: =?ISO-8859-15?Q?Stefan_Sch=E4fer?= User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; de; rv:1.9.1.8) Gecko/20100227 Thunderbird/3.0.3 MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: <51D498BD.3050007@iup.uni-heidelberg.de> <005b01ce798a$b0476600$6d01a8c0@DELL4> <20130706131640.GG5246@cs.utwente.nl> <7D6B8CBB38964C9C82487F5D0F3648FC@FMVXD1232> <20130707203537.GA30691@cs.utwente.nl> <51DA00C8.6000600@iup.uni-heidelberg.de> <51DA0212.8020808@iup.uni-heidelberg.de> <51DA03CE.6020508@iup.uni-heidelberg.de> <51DA1680.6030602@iup.uni-heidelberg.de> <51DB6CB3.2080708@iup.uni-heidelberg.de> <001601ce7c95$f235b360$6401a8c0@JAYDELL> <51DBFF7D.9050807@iup.uni-heidelberg.de> <51DC58E9.5030005@iup.uni-heidelberg.de> <51DF1D06.8020208@iup.uni-heidelberg.de> <51DF43E7.8080300@iup.uni-heidelberg.de> <51E125D4.3050804@virginbroadband.com.au> In-Reply-To: X-Spam-Score: -0.7 (/) 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: Hello Roelof, Is there some progress on your side? I may have some useful informations for you. In the last test i found that i need more gain and in the end i want to have a fiber optic antenna that covers LF and MF, maybe even VLF. Furthermore a resonated antenna is not suitable when the antenna is sometimes grounded or floating in the tests. In my circuit the problem is the low rise- and fall- time of the SFH350V. I saw the problem years ago and ordered a few SFH250V photo diodes which should work well. The LED transmitter is suitable i think, although the SFH757 is faster of course. But i'm always looking below 1 MHz. Now i seareched for some additional ideas for a the optical/electrical converter. Some time ago i built a transimpedance converter but i was sceptic about OP AMPs at 475 kHz. But i think i learned something and got some new ideas on these pages: http://circuits.linear.com/all--Photodiode_Interface_*_Transimpedance_Amps-53 Seems that these frequencies are no problem at all, even if a high gain is desired. The LT6200 is available at RS, 4.56 EUR here. Quite expensive but worth to play with :-) OK, some may say it is overkill and the device can cause VHF oscillations, but anyway... [...] Content analysis details: (-0.7 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.7 RCVD_IN_DNSWL_LOW RBL: Sender listed at http://www.dnswl.org/, low trust [129.206.100.212 listed in list.dnswl.org] 0.0 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain 0.0 HTML_MESSAGE BODY: HTML included in message X-Scan-Signature: b707651713bcd4ad9db4bb0f5d794041 Subject: Re: LF: Re: MiniWhip antenna, fiber optic Content-Type: multipart/alternative; boundary="------------070709050709040808070207" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.0 required=5.0 tests=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 Status: O X-Status: X-Keywords: X-UID: 2804 This is a multi-part message in MIME format. --------------070709050709040808070207 Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Hello Roelof, Is there some progress on your side? I may have some useful informations for you. In the last test i found that i need more gain and in the end i want to have a fiber optic antenna that covers LF and MF, maybe even VLF. Furthermore a resonated antenna is not suitable when the antenna is sometimes grounded or floating in the tests. In my circuit the problem is the low rise- and fall- time of the SFH350V. I saw the problem years ago and ordered a few SFH250V photo diodes which should work well. The LED transmitter is suitable i think, although the SFH757 is faster of course. But i'm always looking below 1 MHz. Now i seareched for some additional ideas for a the optical/electrical converter. Some time ago i built a transimpedance converter but i was sceptic about OP AMPs at 475 kHz. But i think i learned something and got some new ideas on these pages: http://circuits.linear.com/all--Photodiode_Interface_*_Transimpedance_Amps-53 Seems that these frequencies are no problem at all, even if a high gain is desired. The LT6200 is available at RS, 4.56 EUR here. Quite expensive but worth to play with :-) OK, some may say it is overkill and the device can cause VHF oscillations, but anyway... I guess it will be no problem to get the needed gain to go on with the experiments, even if no resonated antenna is used... BTW the output current of the device is even 60 mA. So maybe it is even suitable to drive the LED... What do you think? 73, Stefan/DK7FC Am 13.07.2013 12:55, schrieb Roelof Bakker: > Hello Edgar, > > I don't know how linear these devices are, but that will show up in > actual use. > > The SFH756V and SFH350V are housed in a moulded plastic casing with a > cable clamp: > > http://www.avagotech.com/pages/en/fiber_optics/general_purpose_industrial_control_data_link_650nm/sfh756v/ > > > I also found that for a wider bandwidth the SFH 757V / SFH 250V are > more suitable. > These are rated at 100 MBd. > I will order them in the near future. > > 73, > Roelof Bakker, pa0rdt --------------070709050709040808070207 Content-Type: text/html; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Hello Roelof,

Is there some progress on your side? I may have some useful informations for you.

In the last test i found that i need more gain and in the end i want to have a fiber optic antenna that covers LF and MF, maybe even VLF. Furthermore a resonated antenna is not suitable when the antenna is sometimes grounded or floating in the tests.
In my circuit the problem is the low rise- and fall- time of the SFH350V. I saw the problem years ago and ordered a few SFH250V photo diodes which should work well. The LED transmitter is suitable i think, although the SFH757 is faster of course. But i'm always looking below 1 MHz.
Now i seareched for some additional ideas for a the optical/electrical converter. Some time ago i built a transimpedance converter but i was sceptic about OP AMPs at 475 kHz. But i think i learned something and got some new ideas on these pages:
http://circuits.linear.com/all--Photodiode_Interface_*_Transimpedance_Amps-53
Seems that these frequencies are no problem at all, even if a high gain is desired. The LT6200 is available at RS, 4.56 EUR here. Quite expensive but worth to play with :-) OK, some may say it is overkill and the device can cause VHF oscillations, but anyway...

I guess it will be no problem to get the needed gain to go on with the experiments, even if no resonated antenna is used... BTW the output current of the device is even 60 mA. So maybe it is even suitable to drive the LED...

What do you think?

73, Stefan/DK7FC



Am 13.07.2013 12:55, schrieb Roelof Bakker:
Hello Edgar,

I don't know how linear these devices are, but that will show up in actual use.

The SFH756V and SFH350V are housed in a moulded plastic casing with a cable clamp:

http://www.avagotech.com/pages/en/fiber_optics/general_purpose_industrial_control_data_link_650nm/sfh756v/

I also found that for a wider bandwidth the SFH 757V / SFH 250V are more suitable.
These are rated at 100 MBd.
I will order them in the near future.

73,
Roelof Bakker, pa0rdt
--------------070709050709040808070207--