Return-Path: X-Spam-DCC: paranoid 1233; Body=2 Fuz1=2 Fuz2=2 X-Spam-Checker-Version: SpamAssassin 3.1.3 (2006-06-01) on lipkowski.org X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, HTML_40_50,HTML_MESSAGE autolearn=no version=3.1.3 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by paranoid.lipkowski.org (8.13.7/8.13.7) with ESMTP id t51MEsvv007468 for ; Tue, 2 Jun 2015 00:14:55 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1YzXvL-00005Q-CO for rs_out_1@blacksheep.org; Mon, 01 Jun 2015 23:11:11 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1YzXvK-00005H-JF for rsgb_lf_group@blacksheep.org; Mon, 01 Jun 2015 23:11:10 +0100 Received: from omr-m1.mx.aol.com ([64.12.224.134]) by relay1.thorcom.net with esmtps (TLSv1:DHE-RSA-AES256-SHA:256) (Exim 4.85) (envelope-from ) id 1YzXvH-0008Ak-Rq for rsgb_lf_group@blacksheep.org; Mon, 01 Jun 2015 23:11:09 +0100 Received: from mtaout-mae01.mx.aol.com (mtaout-mae01.mx.aol.com [172.26.254.141]) by omr-m1.mx.aol.com (Outbound Mail Relay) with ESMTP id CA0D338000108 for ; Mon, 1 Jun 2015 18:11:05 -0400 (EDT) Received: from White (ipb21bee4a.dynamic.kabel-deutschland.de [178.27.238.74]) by mtaout-mae01.mx.aol.com (MUA/Third Party Client Interface) with ESMTPA id E1F0F3800009C for ; Mon, 1 Jun 2015 18:11:02 -0400 (EDT) Message-ID: <8525B150A9974B3192BFBF96F6F617A9@White> From: "Markus Vester" To: References: <55650BD1.1070207@posteo.de> <8D2667F9959ECA3-694-18492@webmail-vm121.sysops.aol.com> <556B9BA6.3000808@posteo.de> Date: Tue, 2 Jun 2015 00:11:00 +0200 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=20140625; t=1433196665; bh=P2D70O6VStdIifKElDRd2qIP9FH3T7HKWCqqFq2+hUM=; h=From:To:Subject:Message-ID:Date:MIME-Version:Content-Type; b=oj8PISDjaC33NnmiFNbcjShK+BFkVYR7RLxE3joDJtI0u/sfl9AaSNwIARW4EmwkG PErO2WAsGg/zIUz++2wJVMOYNPljN5PQDwdNuVZYklFNPuo8NDq8MlBhZ2Z0kMlkMn tNHyWA3rwWLrTFCp6npZX12JmobquYzBd5bXsiaE= x-aol-sid: 3039ac1afe8d556cd8763783 X-AOL-IP: 178.27.238.74 X-Scan-Signature: 81e655fcf3a8bdab256d37a53bc8dabb Subject: Re: LF: Small MF ferrite antenna games Content-Type: multipart/alternative; boundary="----=_NextPart_000_001C_01D09CC8.9B8855E0" 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 X-Scanned-By: MIMEDefang 2.56 on 10.1.3.10 Status: O X-Status: X-Keywords: X-UID: 3403 Dies ist eine mehrteilige Nachricht im MIME-Format. ------=_NextPart_000_001C_01D09CC8.9B8855E0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Stefan, >> Is it possible to 'build' a cardioid antenna by combing the signals = of E and H within SpecLab? It is only a mixing of these two signals with = a different 'weight', right? This could be done in the 'left to right = output amp', right?=20 Yes, this should be possible, although I never actually tried it that = way. The weight factor can be made positive or negative for pointing the = main lobe eg. west or east. Note that you will have to adjust the analog = hardware such that the phase difference between the whip and the loop = channel is either 0=C2=B0 or 180=C2=B0, so that the signal from the = unwanted direction can cancel. > I assume i will need a relay to select one of the two loops to feed it = to the RX, but what happens if i use the combined loop signal to try = that? If you use the 90=C2=B0 combined signal, you still get a null in the = back side of the cardioid - this is what can be selected as "single, = sharp cardioid" in SpecLab's RDF menue. Despite of having only two = input channels, you can conveniently point the antenna in any direction = by software. The difference to the "classic" cardioid pattern is that = the "other" loop antenna also contributes signals from the sides, = effectively reducing the forward gain and making the null sharper ( = |cos| instead of cos^2 pattern).=20 Usually that sharper null is more of a disadvantage, for example if you = want to suppress QRN from a range of angles around the back side (eg. = statics from southeast Europe). But occasionally sharpness can help to = null an undesired signal coming in from a direction near that of the = desired signal.=20 All the best, Markus (DF6NM) From: DK7FC=20 Sent: Monday, June 01, 2015 1:39 AM To: rsgb_lf_group@blacksheep.org=20 Subject: Re: LF: Small MF ferrite antenna games Hi Markus,=20 Yes yes, great ideas. I will go on step by step. First i need to = configure the link in stereo mode and see if it runs stable. The = mono-stream needs about 220 kBit/s. It's availability is fine now over = 2.4 km even in slight rain. I assume it will work. If this runs stable = then i can build a stereo-RX. Is it possible to 'build' a cardioid antenna by combing the signals of E = and H within SpecLab? It is only a mixing of these two signals with a = different 'weight', right? This could be done in the 'left to right = output amp', right? I assume i will need a relay to select one of the = two loops to feed it to the RX, but what happens if i use the combined = loop signal to try that? 73, Stefan Am 27.05.2015 12:32, schrieb Markus Vester:=20 Yes Stefan, bring colour into your life ;-) Even after more than 10 = years, I still sometimes enjoy just sitting and watching things roll by = on the colour-RDF screen.=20 With crossed loops and an E-field antenna you have a number of = options.=20 1. The colour-DF scheme takes the E-field on one channel and a = 90=C2=B0-combination from two loops on the second, providing = omnidirectional reception with 360=C2=B0 RDF functionality. The combiner = is simple to make, and you'll have to add a second RX channel. A stereo = soundcard can be used, and SpecLab has everything needed onboard. Having = a 475 kHz directional grabber available in Heidelberg would surely be = very useful to the community. 2. Then you can hardware-combine whip and loop for a unidirectional = cardioid pattern. This is equivalent to K9AY or similar antennas, which = on LF have provided outstanding results for a few observers in quiet = locations. The crossed loops can be used with electronic steering or a = small goniometer, which allow you to virtually rotate the cardioid in = the shack. Note that the phase-based colour-DF scheme still works if the = cardoid antenna instead of the whip is used as intensity source. I have = tried this on LF, but in my location SNR gain was not up to expectations = because my loops are too much affected by noise from underground cables. = 3. The next step would be downconverting and digitizing all three = channels separately, allowing you to steer the cardioid by software and = even monitor different beam headings simultaneously. But a three channel = digitizer is not so easily available, and you'll need dedicated software = for postprocessing. Paul Nicholson can do this at VLF, using three = stereo soundcards augmented by GPS ticks, and a posteriori = synchronisation in his own software.=20 All the best, Markus (DF6NM) -----Urspr=C3=BCngliche Mitteilung-----=20 Von: DK7FC An: rsgb_lf_group Verschickt: Mi, 27 Mai 2015 2:13 am Betreff: LF: Small MF ferrite antenna games MF,=20 Today i've played a bit with a small ferrite antenna for 630m.=20 It is 14 cm long and has 8 mm diameter.=20 Without any calculations i wound a winding of unknown number of turns =20 around the rod and quickly found C about 200 pF at resonance (475 kHz).=20 Then i added a few turns for a 50 Ohm output (measuring the voltage of =20 an induced signal at resonance. When applying 50 Ohm, the voltage has to = =20 decrease to 50%) to the RX.=20 https://dl.dropboxusercontent.com/u/19882028/MF/small%20MF%20ferrite%20an= tenna.jpg=20 As expected the input signal is to low, it does not rise the noise of =20 the RX, so i'm missing about 20 dB. It can't be much more though because = =20 i can receive IQ2MI/B clearly in QRSS-30 on 476.180 kHz with 25 dB SNR =20 in 122 mHz, see attachment.=20 The antenna is hanging in 6m AGL in a tree in my garden...=20 I'm playing with the idea of a rotary H-field RX antenna for MF, maybe =20 in combination with a stereo receiver and a E-field antenna. Oh and =20 maybe with a colour spectrogram as known from DF6NM. A lot of things to = do :-)=20 73, Stefan=20 PS: Yesterday, in a CW QSO with DK6SX/p on the loop he once completely = disappered into QSO which never happend before when receiving on a =20 omni-directional antenna. So i guess the colour changes in such a =20 spectrogram must be quite interesting and informative...=20 ------=_NextPart_000_001C_01D09CC8.9B8855E0 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Stefan,
 
>> Is it possible to 'build' a = cardioid=20 antenna by combing the signals of E and H within SpecLab? It is only a = mixing of=20 these two signals with a different 'weight', right? This could be done = in the=20 'left to right output amp', right?
 
Yes, this should be possible, = although I never=20 actually tried it that way. The weight factor can be made positive or = negative=20 for pointing the main lobe eg. west or east. Note that you will = have to=20 adjust the analog hardware such that the phase difference between = the whip=20 and the loop channel is either 0=C2=B0 or 180=C2=B0, so that the = signal from the=20 unwanted direction can cancel.
 
> I assume i will need a relay to = select one of=20 the two loops to feed it to the RX, but what happens if i use the = combined loop=20 signal to try that?
If you use the 90=C2=B0 combined = signal, you still=20 get a null in the back side of the cardioid - this is what can be = selected=20 as "single, sharp cardioid" in SpecLab's RDF menue.  Despite of = having only=20 two input channels, you can conveniently point the antenna in any = direction=20 by software. The difference to the "classic" cardioid pattern is=20 that the "other" loop antenna also contributes signals from = the sides,=20 effectively reducing the forward gain and making the null sharper ( = |cos|=20 instead of cos^2 pattern). 
 
Usually that sharper null is more = of a=20 disadvantage, for example if you want to suppress QRN = from a=20 range of angles around the back side (eg. statics from southeast=20 Europe). But occasionally sharpness can help to null=20 an undesired signal coming in from a = direction near that of=20 the desired signal.
 
All the best,
Markus (DF6NM)
 
 

From:=20 DK7FC
Sent: Monday, June 01, = 2015 1:39=20 AM
To: rsgb_lf_group@blacksheep.org
Subject: Re: LF: Small MF = ferrite=20 antenna games

Hi Markus,

Yes yes, great = ideas. I will go=20 on step by step. First i need to configure the link in stereo mode and = see if it=20 runs stable. The mono-stream needs about 220 kBit/s. It's availability = is fine=20 now over 2.4 km even in slight rain. I assume it will work. If this runs = stable=20 then i can build a stereo-RX.
Is it possible to 'build' a cardioid = antenna by=20 combing the signals of E and H within SpecLab? It is only a mixing of = these two=20 signals with a different 'weight', right? This could be done in the = 'left to=20 right output amp', right? I assume i will need a relay to select one of = the two=20 loops to feed it to the RX, but what happens if i use the combined loop = signal=20 to try that?

73, Stefan


Am 27.05.2015 12:32, schrieb = Markus=20 Vester:
Yes = Stefan,=20 bring colour into your life ;-) Even after more than 10 years, I still = sometimes enjoy just sitting and watching things roll by on the = colour-RDF=20 screen.
 
With = crossed=20 loops and an E-field antenna you have a number of options.
 
1. = The=20 colour-DF scheme takes the E-field on one channel and a = 90=C2=B0-combination from=20 two loops on the second, providing omnidirectional reception with = 360=C2=B0 RDF=20 functionality. The combiner is simple to make, and you'll have to add = a second=20 RX channel. A stereo soundcard can be used, and SpecLab has everything = needed=20 onboard. Having a 475 kHz directional grabber available in Heidelberg = would=20 surely be very useful to the community.
 
2. = Then you can=20 hardware-combine whip and loop for a unidirectional cardioid pattern. = This is=20 equivalent to K9AY or similar antennas, which on LF have provided = outstanding=20 results for a few observers in quiet locations. The crossed loops can = be used=20 with electronic steering or a small goniometer, which allow you to = virtually=20 rotate the cardioid in the shack. Note that the phase-based colour-DF = scheme=20 still works if the cardoid antenna instead of the whip is used as = intensity=20 source. I have tried this on LF, but in my location SNR gain was not = up to=20 expectations because my loops are too much affected by noise from = underground=20 cables.
 
3. = The next=20 step would be downconverting and digitizing all three channels = separately,=20 allowing you to steer the cardioid by software and even monitor = different beam=20 headings simultaneously. But a three channel digitizer is not so = easily=20 available, and you'll need dedicated software for postprocessing. Paul = Nicholson can do this at VLF, using three stereo soundcards augmented = by GPS=20 ticks, and a posteriori synchronisation in his own software.
 
All = the=20 best,
Markus (DF6NM)
-----Urspr=C3=BCngliche=20 Mitteilung-----
Von: DK7FC <selberdenken@posteo.de>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: Mi, 27 Mai 2015 2:13 am
Betreff: = LF: Small MF=20 ferrite antenna games

MF,=20

Today i've played a bit with a small ferrite antenna for 630m.=20
It is 14 cm long and has 8 mm diameter.=20
Without any calculations i wound a winding of unknown number of turns  =

around the rod and quickly found C about 200 =
pF at resonance (475 kHz).=20

Then i added a few turns for a 50 Ohm output (measuring the voltage of =20
an induced signal at resonance. When applying 50 Ohm, the voltage has to =
=20
decrease to 50%) to the RX.=20

https://dl.dropboxusercontent.com/u/19882028/MF/small%20MF%2=
0ferrite%20antenna.jpg=20

As expected the input signal is to low, it does not rise the noise of =20
the RX, so i'm missing about 20 dB. It can't be much more though because =
=20
i can receive IQ2MI/B clearly in QRSS-30 on 476.180 kHz with 25 dB SNR =20
in 122 mHz, see attachment.=20

The antenna is hanging in 6m AGL in a tree in my garden...=20

I'm playing with the idea of a rotary H-field RX antenna for MF, maybe =20
in combination with a stereo receiver and a E-field antenna. Oh and =20
maybe with a colour spectrogram as known from DF6NM. A lot of things to  =

do :-)=20

73, Stefan=20

 PS: Yesterday, in a CW QSO with DK6SX/p on the loop he once completely  =

disappered into QSO which never happend before when receiving on a =20
omni-directional antenna. So i guess the colour changes in such a =20
spectrogram must be quite interesting and informative...=20
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