Return-Path: X-Spam-DCC: paranoid 1102; 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=-0.3 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, HTML_30_40,HTML_MESSAGE,RATWARE_GECKO_BUILD 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 t4VNgNLd003448 for ; Mon, 1 Jun 2015 01:42:23 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1YzCpB-0005pF-5p for rs_out_1@blacksheep.org; Mon, 01 Jun 2015 00:39:25 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1YzCpA-0005p6-JI for rsgb_lf_group@blacksheep.org; Mon, 01 Jun 2015 00:39:24 +0100 Received: from mx02.posteo.de ([89.146.194.165]) by relay1.thorcom.net with esmtps (TLSv1.2:DHE-RSA-AES256-GCM-SHA384:256) (Exim 4.85) (envelope-from ) id 1YzCp7-0004zH-9E for rsgb_lf_group@blacksheep.org; Mon, 01 Jun 2015 00:39:23 +0100 Received: from dovecot03.posteo.de (unknown [185.67.36.28]) by mx02.posteo.de (Postfix) with ESMTPS id 31A9225A3DD4 for ; Mon, 1 Jun 2015 01:39:20 +0200 (CEST) Received: from mail.posteo.de (localhost [127.0.0.1]) by dovecot03.posteo.de (Postfix) with ESMTPSA id 3m0GLc0w22z5vN0 for ; Mon, 1 Jun 2015 01:39:20 +0200 (CEST) Message-ID: <556B9BA6.3000808@posteo.de> Date: Mon, 01 Jun 2015 01:39:18 +0200 From: DK7FC 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: <55650BD1.1070207@posteo.de> <8D2667F9959ECA3-694-18492@webmail-vm121.sysops.aol.com> In-Reply-To: <8D2667F9959ECA3-694-18492@webmail-vm121.sysops.aol.com> X-Scan-Signature: 14522a7d8bfffcae5e92e35059f18ae1 Subject: Re: LF: Small MF ferrite antenna games Content-Type: multipart/alternative; boundary="------------050909000408060900040606" 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: 3389 This is a multi-part message in MIME format. --------------050909000408060900040606 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit 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 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: > 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. > 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°-combination from two loops on the second, providing > omnidirectional reception with 360° 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. > All the best, > Markus (DF6NM) > > > -----Ursprüngliche 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%20antenna.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... > > > > > --------------050909000408060900040606 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 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:
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.
 
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°-combination from two loops on the second, providing omnidirectional reception with 360° 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.
 
All the best,
Markus (DF6NM)


-----Ursprüngliche 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 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%20antenna.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...


--------------050909000408060900040606--