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=-2.1 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, FORGED_RCVD_HELO,HTML_50_60,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 t526Ckcj008500 for ; Tue, 2 Jun 2015 08:12:46 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1YzfKw-0000a9-Te for rs_out_1@blacksheep.org; Tue, 02 Jun 2015 07:06:06 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1YzfKw-0000a0-6x for rsgb_lf_group@blacksheep.org; Tue, 02 Jun 2015 07:06:06 +0100 Received: from rhcavuit01.kulnet.kuleuven.be ([134.58.240.129] helo=cavuit01.kulnet.kuleuven.be) by relay1.thorcom.net with esmtp (Exim 4.85) (envelope-from ) id 1YzfKt-0000UW-Ht for rsgb_lf_group@blacksheep.org; Tue, 02 Jun 2015 07:06:05 +0100 X-KULeuven-Envelope-From: rik.strobbe@fys.kuleuven.be X-KULeuven-Scanned: Found to be clean X-KULeuven-ID: 1B34C1380DE.A29C3 X-KULeuven-Information: Katholieke Universiteit Leuven Received: from icts-p-smtps-2.cc.kuleuven.be (icts-p-smtps-2e.kulnet.kuleuven.be [134.58.240.34]) by cavuit01.kulnet.kuleuven.be (Postfix) with ESMTP id 1B34C1380DE for ; Tue, 2 Jun 2015 08:05:56 +0200 (CEST) Received: from ICTS-S-HUB2.luna.kuleuven.be (icts-s-hub2.luna.kuleuven.be [10.112.9.16]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (No client certificate requested) by icts-p-smtps-2.cc.kuleuven.be (Postfix) with ESMTPS id 16FDC20098 for ; Tue, 2 Jun 2015 08:05:56 +0200 (CEST) Received: from ICTS-S-MBX1.luna.kuleuven.be ([fe80::edaf:341f:90e:f70e]) by ICTS-S-HUB2.luna.kuleuven.be ([fe80::8559:ca7c:e195:e15d%26]) with mapi id 14.03.0224.002; Tue, 2 Jun 2015 08:05:55 +0200 X-Kuleuven: This mail passed the K.U.Leuven mailcluster From: Rik Strobbe To: "rsgb_lf_group@blacksheep.org" Thread-Topic: LF: Small MF ferrite antenna games Thread-Index: AQHQmBIaaq8X/OtMjUSiCFaIhANdm52Pf0KAgAclGACAAZwtbYAAf8yngAAD7Vw= Date: Tue, 2 Jun 2015 06:05:54 +0000 Message-ID: <7E7DFBB4D102A04DB5ADC88D66628A4A2355E53F@ICTS-S-MBX1.luna.kuleuven.be> References: <55650BD1.1070207@posteo.de> <8D2667F9959ECA3-694-18492@webmail-vm121.sysops.aol.com> <556B9BA6.3000808@posteo.de>,<8525B150A9974B3192BFBF96F6F617A9@White> In-Reply-To: <8525B150A9974B3192BFBF96F6F617A9@White> Accept-Language: nl-BE, en-GB, en-US Content-Language: nl-BE X-MS-Has-Attach: X-MS-TNEF-Correlator: x-mimectl: Produced By Microsoft Exchange V14.3.123.2 x-originating-ip: [10.112.13.12] MIME-Version: 1.0 X-HELO-Warning: Remote host 134.58.240.129 (rhcavuit01.kulnet.kuleuven.be) used invalid HELO/EHLO cavuit01.kulnet.kuleuven.be - verification failed X-Scan-Signature: 08189ecf0514bcba2be8490569e8d13c Subject: RE: LF: Small MF ferrite antenna games Content-Type: multipart/alternative; boundary="_000_7E7DFBB4D102A04DB5ADC88D66628A4A2355E53FICTSSMBX1lunaku_" 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: 3404 --_000_7E7DFBB4D102A04DB5ADC88D66628A4A2355E53FICTSSMBX1lunaku_ Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hi Stefan, getting a cardioid antenna using a magnetic ferrite rod (or loop) antenna a= nd an small electrical antenna is very simple and done for ages in 80m ARDF= (foxhunt) receivers. Sure it can be done with SpecLab, but it maybe oversh= oot. Just to be sure: you will need to sum the signals of both antennas, not mix= (multiply) them. The most critical factor to get a deep null is to ensure that the ferrite r= od / loop antenna is properly shielded in order to avoid that it does pick= up any E-field. Effective shielding is rather easy with a ferrite rod antenna: just put the= rod inside a 'sliced' aluminium tube. 73, Rik ON7YD - OR7T ________________________________ Van: owner-rsgb_lf_group@blacksheep.org [owner-rsgb_lf_group@blacksheep.org= ] namens Markus Vester [markusvester@aol.com] Verzonden: dinsdag 2 juni 2015 0:11 Aan: rsgb_lf_group@blacksheep.org Onderwerp: Re: LF: Small MF ferrite antenna games 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 diff= erent 'weight', right? This could be done in the 'left to right output amp'= , right? 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 lo= be 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 eit= her 0=B0 or 180=B0, so that the signal from the unwanted direction can canc= el. > 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=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 ca= n conveniently point the antenna in any direction by software. The differen= ce to the "classic" cardioid pattern is that the "other" loop antenna also = contributes signals from the sides, effectively reducing the forward gain a= nd making the null sharper ( |cos| instead of cos^2 pattern). Usually that sharper null is more of a disadvantage, for example if you wan= t 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 unde= sired signal coming in from a direction near that of the desired signal. All the best, Markus (DF6NM) From: DK7FC Sent: Monday, June 01, 2015 1:39 AM To: rsgb_lf_group@blacksheep.org Subject: Re: LF: Small MF ferrite antenna games Hi Markus, 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 ab= out 220 kBit/s. It's availability is fine now over 2.4 km even in slight ra= in. 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 an= d H within SpecLab? It is only a mixing of these two signals with a differe= nt 'weight', right? This could be done in the 'left to right output amp', r= ight? I assume i will need a relay to select one of the two loops to feed i= t 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: 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 col= our-RDF screen. With crossed loops and an E-field antenna you have a number of options. 1. The colour-DF scheme takes the E-field on one channel and a 90=B0-combin= ation from two loops on the second, providing omnidirectional reception wit= h 360=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 ha= s 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 cardioi= d pattern. This is equivalent to K9AY or similar antennas, which on LF have= provided outstanding results for a few observers in quiet locations. The c= rossed loops can be used with electronic steering or a small goniometer, wh= ich 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 lo= cation SNR gain was not up to expectations because my loops are too much af= fected 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 n= ot so easily available, and you'll need dedicated software for postprocessi= ng. Paul Nicholson can do this at VLF, using three stereo soundcards augmen= ted by GPS ticks, and a posteriori synchronisation in his own software. All the best, Markus (DF6NM) -----Urspr=FCngliche Mitteilung----- Von: DK7FC An: rsgb_lf_group Verschickt: Mi, 27 Mai 2015 2:13 am Betreff: LF: Small MF ferrite antenna games MF, Today i've played a bit with a small ferrite antenna for 630m. It is 14 cm long and has 8 mm diameter. 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). Then i added a few turns for a 50 Ohm output (measuring the voltage of an induced signal at resonance. When applying 50 Ohm, the voltage has to decrease to 50%) to the RX. https://dl.dropboxusercontent.com/u/19882028/MF/small%20MF%20ferrite%20ante= nna.jpg As expected the input signal is to low, it does not rise the noise of the RX, so i'm missing about 20 dB. It can't be much more though because i can receive IQ2MI/B clearly in QRSS-30 on 476.180 kHz with 25 dB SNR in 122 mHz, see attachment. The antenna is hanging in 6m AGL in a tree in my garden... I'm playing with the idea of a rotary H-field RX antenna for MF, maybe in combination with a stereo receiver and a E-field antenna. Oh and maybe with a colour spectrogram as known from DF6NM. A lot of things to do :-) 73, Stefan 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 omni-directional antenna. So i guess the colour changes in such a spectrogram must be quite interesting and informative... --_000_7E7DFBB4D102A04DB5ADC88D66628A4A2355E53FICTSSMBX1lunaku_ Content-Type: text/html; charset="iso-8859-1" Content-ID: Content-Transfer-Encoding: quoted-printable

Hi Stefan,

 

getting a cardioid antenna using a magnetic ferrite rod (or loop) antenna and an small electrical antenna is very simple and done for ages in 80m ARDF (f= oxhunt) receivers. S= ure it can be done with SpecLab, but i= t maybe overshoot.

Just to be sure:&= nbsp;you will n= eed to sum the = signals of both ante= nnas, not mix (multiply) them.

The most critical factor to get a deep null is to ensure that the ferrite rod  / loop antenna is properly shielded in order to avoid&= nbsp;that it does&nb= sp;pick up any E-fie= ld.

Effective shielding is rather easy with a ferrite rod antenna: just= put the rod inside= a 'sliced' aluminium tube.

 

73, Rik  ON7YD - OR7T

 

Van: owner-rsgb_lf_group@blacksheep.org [ow= ner-rsgb_lf_group@blacksheep.org] namens Markus Vester [markusvester@aol.co= m]
Verzonden: dinsdag 2 juni 2015 0:11
Aan: rsgb_lf_group@blacksheep.org
Onderwerp: Re: LF: Small MF ferrite antenna games

Stefan,
 
>> Is it possible to 'build' a c= ardioid antenna by combing the signals of E and H within SpecLab? It is onl= y a mixing of these two signals with a different 'weight', right? This coul= d be done in the 'left to right output amp', right?
 
Yes, this should be possible, alt= hough I never actually tried it that way. The weight factor can be made pos= itive or negative for pointing the main lobe eg. west or east. Note th= at you will have to adjust the analog hardware such that the phase difference between the whip and the loop channel = is either 0=B0 or 180=B0, so that the signal from the unwanted directi= on can cancel.
 
> I assume i will need a relay to s= elect 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=B0 combined signal, = you still get a null in the back side of the cardioid - this is w= hat 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 diff= erence to the "classic" cardioid pattern is that the &q= uot;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). 
 
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 Eur= ope). But occasionally sharpness can help to null an un= desired signal coming in from a direction near that of the desired = signal.
 
All the best,
Markus (DF6NM)
 
 

From: <= a title=3D"selberdenken@posteo.de" href=3D"mailto:selberdenken@posteo.de" t= arget=3D"_blank">DK7FC=
Sent: Monday, June 01, 20= 15 1:39 AM
Subject: Re: LF: Small MF= ferrite antenna games

Hi Markus,

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 ab= out 220 kBit/s. It's availability is fine now over 2.4 km even in slight ra= in. 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 an= d H within SpecLab? It is only a mixing of these two signals with a differe= nt 'weight', right? This could be done in the 'left to right output amp', r= ight? 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:
Yes Stefan= , bring colour into your life ;-) Even after more than 10 years, I still so= metimes enjoy just sitting and watching things roll by on the colour-RDF sc= reen.
 
With cross= ed loops and an E-field antenna you have a number of options.
 
1. The col= our-DF scheme takes the E-field on one channel and a 90=B0-combination from= two loops on the second, providing omnidirectional reception with 360=B0 R= DF functionality. The combiner is simple to make, and you'll have to add a second RX channel. A stereo soundcard ca= n be used, and SpecLab has everything needed onboard. Having a 475 kHz dire= ctional grabber available in Heidelberg would surely be very useful to the = community.
 
2. Then yo= u 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 c= ardoid antenna instead of the whip is used as intensity source. I have tried this on LF, but in my location S= NR gain was not up to expectations because my loops are too much affected b= y noise from underground cables.
 
3. The nex= t 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 sync= hronisation in his own software.
 
All the be= st,
Markus (DF6NM)
-----Urspr=FCngliche Mitteilung-----
Von: DK7FC <selb= erdenken@posteo.de>
An: rsgb_lf_group &= lt;rsgb_lf_group@blacksheep.org>
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  
around the rod and quickly found C about 20=
0 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 =20
do :-)=20

73, Stefan=20

 PS: Yesterday, in a CW QSO with DK6SX/p on the loop he once completely =20
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
--_000_7E7DFBB4D102A04DB5ADC88D66628A4A2355E53FICTSSMBX1lunaku_--