Return-Path: Received: from mtain-de08.r1000.mx.aol.com (mtain-de08.r1000.mx.aol.com [172.29.64.208]) by air-df07.mail.aol.com (v129.4) with ESMTP id MAILINDF074-5efd4ca0dd9f2e9; Mon, 27 Sep 2010 14:08:31 -0400 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-de08.r1000.mx.aol.com (Internet Inbound) with ESMTP id DD27B380000A2; Mon, 27 Sep 2010 14:08:28 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1P0I6W-0003G6-GQ for rs_out_1@blacksheep.org; Mon, 27 Sep 2010 19:07:08 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1P0I6L-0003FH-K7 for rsgb_lf_group@blacksheep.org; Mon, 27 Sep 2010 19:06:57 +0100 Received: from relay.uni-heidelberg.de ([129.206.100.212]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1P0I6L-0005Jz-ET for rsgb_lf_group@blacksheep.org; Mon, 27 Sep 2010 19:06:58 +0100 Received: from ix.urz.uni-heidelberg.de (cyrus-portal.urz.uni-heidelberg.de [129.206.100.176]) by relay.uni-heidelberg.de (8.14.1/8.14.1) with ESMTP id o8RI6NF5020888 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Mon, 27 Sep 2010 20:06:23 +0200 Received: from extmail.urz.uni-heidelberg.de (extmail.urz.uni-heidelberg.de [129.206.100.140]) by ix.urz.uni-heidelberg.de (8.13.8/8.13.8) with ESMTP id o8RI6tYf017042 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Mon, 27 Sep 2010 20:06:55 +0200 Received: from [129.206.196.209] (vpn209a.rzuser.uni-heidelberg.de [129.206.196.209]) by extmail.urz.uni-heidelberg.de (8.13.4/8.13.1) with ESMTP id o8RI6K6J006865 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Mon, 27 Sep 2010 20:06:22 +0200 Message-ID: <4CA0DD3B.1090408@iup.uni-heidelberg.de> Date: Mon, 27 Sep 2010 20:06:51 +0200 From: =?ISO-8859-1?Q?Stefan_Sch=E4fer?= User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; de; rv:1.9.1.11) Gecko/20100711 Thunderbird/3.0.6 MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: <4C9D17FF.4040004@iup.uni-heidelberg.de> <003b01cb5e54$43a8f080$0401a8c0@xphd97xgq27nyf> In-Reply-To: <003b01cb5e54$43a8f080$0401a8c0@xphd97xgq27nyf> X-Spam-Score: 1.6 (+) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001,HTML_TAG_EXIST_TBODY=0.126,RATWARE_GECKO_BUILD=1.426 Subject: Re: LF: DK7FC now on 137.715 in DFCW4 with his 600m earth antenna Content-Type: multipart/alternative; boundary="------------070502010603030107020402" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.6 required=5.0 tests=HTML_MESSAGE, HTML_TAG_EXISTS_TBODY,HTML_TITLE_EMPTY 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 x-aol-global-disposition: S X-AOL-REROUTE: YES x-aol-sid: 3039ac1d40d04ca0dd9c169d X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none X-Mailer: Unknown (No Version) --------------070502010603030107020402 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: quoted-printable X-MIME-Autoconverted: from 8bit to quoted-printable by relay.uni-heidelberg.de id o8RI6NF5020888 Mal, LF, It is a wire, 4 m above ground. It is grounded at the far end, using 20=20 * 0,4 m loong copper rods, about 1m spaced. The same ground electrode=20 array is near the other end of the antenna. The RF is applied at this=20 point, so between one earth electrode and the wire. RF power was about=20 100 W in this test. The antenna was not resonated or matched to 50 Ohm but the PA remained=20 absolutely cold, so all the power (measured on the DC side ( P=3D 12,5 V= *=20 8,5 A)) must have been applied to the antenna. I will take an=20 Oscilloscope to the antenna soon and will measure the U/I ratio and the=20 phase. Then i can add some C and a suitable step up transformer. If=20 Z=3DR=3D50 Ohm i can apply my class E PA as well... Also, i will built an amperemeter (using a current transformer and a=20 bridge rectifier) to measure the antenna current on all frequencies,=20 since my digital amperemeter can measure on 8.97 kHz but not on 137 kHz... Mal, what ARGO settings do you use? QRSS-3, normal should be suitable.=20 My DFCW was 4 seconds dot and 1 second break between the elements. I am=20 using RIKs QRS program. Will switch to QRSS the next time (not only but=20 sometimes ;-) ). On sunday i have tested the IC-706 as a RX. For attenuation a had just=20 the possibility to use the internal attenuator. But this is all still=20 not working fine. I could not even receive OE5ODL. So i have to work on=20 this side... Has anyone a ready to use circuit for a homemade LF RX that uses a high=20 power signal? LF RX means that i do not need an extra HF TRX to make=20 signals audible. So the signal must be shifted down to the range where=20 the soundcard is working or even to audible frequencies. And the input=20 should be suitable for strong signals... :-) 73, es CU Stefan/DK7FC Am 27.09.2010 16:57, schrieb mal hamilton: > I see some confusion here as regards Earth antennas. > Is this antenna a wire x metres above ground and grounded at one end=20 > and fed with rf at the other ? if so then it is a grounded loop of=20 > some sort. > or > is it two long insulated wires lying on the ground and each wire=20 > grounded by a stake at one end and the other end pair fed with rf ? > Please be more clear about this type of antenna system. > I was able to see some DFCW signal broken up on Friday but no ID=20 > because the elements were too close together, more spacing between=20 > elements or QRS 10 and I could have got an ID > A missed opportunity for a DX report, the signal could have been=20 > DK7FC because of the QRG and QTR but this is NOT proof of signal. > I have a couple of screen shots as proof of a signal. > de G3KEV > > ----- Original Message ----- > *From:* Roger Lapthorn > *To:* rsgb_lf_group@blacksheep.org > > *Sent:* Saturday, September 25, 2010 12:28 PM > *Subject:* Fwd: Re: LF: DK7FC now on 137.715 in DFCW4 with his > 600m earth antenna > > ---------- Forwarded message ---------- > From: *Stefan Sch=E4fer* > > Date: 2010/9/24 > Subject: Fwd: Re: LF: DK7FC now on 137.715 in DFCW4 with his 600m > earth antenna > To: Roger Lapthorn > > > > Hello Roger, > > Below you find my eport on the todays LF earth antennas test. > Currently it seems not possible for me to send to the reflector. I > even do not get mails from there... (?) > > Markus/DF6NM has forwarded the mail to the reflector but it wasn't > reflected. Maybe, you can try to forward it? Can you tell me if it > was reflected? > > The mail contains some infos about my todays activity on VLF/LF! > So could be interesting to some RX stations :-) > > Best 73, Stefan/DK7FC > > -------- Original-Nachricht -------- > Betreff: Re: LF: DK7FC now on 137.715 in DFCW4 with his 600m > earth antenna > Datum: Fri, 24 Sep 2010 22:02:59 +0200 > Von: Stefan Sch=E4fer > > An: Renato Romero , Paul > > > > > Hello Marco, Michel, John, LF, > > This is a great day for the optimists, regarding *EARTH ANTENNAs > as a TX antenna!* :-) > > Until today i have not spend too much attention to my earth > antenna as a TX antenna on LF. But knowing that my small PA for > VLF (12V/300W class D) can also transmit on 137 kHz i gave it a > first try today. I was almost sure that my signal will be visible > on my grabber in 5 km distance but wasn't sure how the efficiency > really is... > > We know that the effective area of the formed loop must be smaller > than on VLF but the big advantage seems to be that the antenna is > even longer than lambda/4 for 2200m! Thus, to my surprise, and > probably to the surprise of the most of you, the antenna seems to > be very suitable as a TX antenna although the average height of > the wire above ground is just about 4m!! The ground resistance is > about 600 Ohm, currently. > I am VERY happy now to have a fixed antenna in a quiet location > that does not matter of rain and wind or so and can be used from > DC to HF :-) > A first transmission at *25 W* was immediately visible on the > DD7PC grabber, about *20 dB above noise in DFCW-3, distance is 77 > km*. So, it must have been audible! > A later transmission at 100 W is visible in France, with a good > S/N. Many TNX to Michel and John! If the signal was 20 dB above > noise in DFCW-3 at John's QTH in *JN17VG (436 km)*, it must have > been audible as well! :-) > > Indeed, i have also never expected this efficiency from an earth > antenna. It is months ago that i tried to convince some people > here to try such an antenna. Maybe this day can help to convince > practical oriented people that it is worth trying things that > seems to be "wasted time" and/or "impossible" :-))) > > I also hope that an earth antenna will be seen as an alternative > to a normal closed loop or a vertical, especially in a woody region. > > Attached you find a screenshot of my grabber and my signal in 5 km > distance. Maybe it was 100 dB above noise? ;-))) > > I still have no RX that can handle this big input signal. My 706 > is not the best idea and i have most of my LF equipment on the > parents QTH but i will try to receive tomorrow with the 706 and my > PC on the earth antenna, using some attenuators and/or > transformers. I will build a suitable RX for this antenna soon. > But the QTH is EXCELLENT as you can image :-) > > So, there was a discussion about the radiation pattern of an earth > antenna, if it acts as a loop or not. Since the antenna length is > in the region a lambda, it surely will not be a pure loop and will > maybe have a preferred direction. YOU all can help to find out > this radiation pattern by listening to my transmissions that will > be done in the next days. *Tomorrow, arround 8 UTC i will do a VLF > test and later a LF test on the earth antenna.* The VLF test is to > reach Michael Oexner again and later on LF i would appreciate any > rprts. But still not sure if i can come to QSO mode, due to the RX. > > Now i know that this antenna is very worth to keep and improve. > This will be done in the next weeks! :-) > > *BTW: I cannot transmit on sunday with the kite antenna, due to > the WX, sri...* > > If some people want to try an earth antenna as a TX antenna, you > can ask me any questions! > > Sorry, i am a little euphoric now. The best sign if this happens > during a project. Can it be wasted time then? > > > Best 73 and hope cuagn on LF this period! > > Stefan/DK7FC > > > > > Am 24.09.2010 17:27, schrieb Michel Brunel: >> Hello Marco, LF, >> >> Excellent copy here in JN18HP, hope the capture find its way throug= h the >> reflector. >> I was definitely not expecting such a signal with an earth electrod= e ! >> >> 73 >> >> Michel - F5WK >> >> >> >> =20 >>> Hello LF, >>> Stefan, DK7FC is transmitting with his 600m earth antenna on +/-= 137.715KHz in DFCW4. >>> I could see him on my Grabber (see attachment) >>> http://www.qsl.net/dd7pc/lfgrabber_dd7pc.html and on the grabber= from >>> Markus, DF6NM with a very good signal. >>> He was transmitting just with 25W and will increase now to 100W. >>> Any reports of his transmission are very welcome. >>> =20 >> =20 >>> Vy73 >>> Marco >>> DD7PC >>> =20 > > > > --=20 > http://g3xbm-qrp.blogspot.com/ > http://www.g3xbm.co.uk > http://www.youtube.com/user/g3xbm > G3XBM GQRP 1678 ISWL G11088 > --------------070502010603030107020402 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Mal, LF,

It is a wire, 4 m above ground. It is grounded at the far end, using 20 * 0,4 m loong copper rods, about 1m spaced. The same ground electrode array is near the other end of the antenna. The RF is applied at this point, so between one earth electrode and the wire. RF power was about 100 W in this test.

The antenna was not resonated or matched to 50 Ohm but the PA remained absolutely cold, so all the power (measured on the DC side ( P= 12,5 V * 8,5 A)) must have been applied to the antenna. I will take an Oscilloscope to the antenna soon and will measure the U/I ratio and the phase. Then i can add some C and a suitable step up transformer. If Z=R=50 Ohm i can apply my class E PA as well...

Also, i will built an amperemeter (using a current transformer and a bridge rectifier) to measure the antenna current on all frequencies, since my digital amperemeter can measure on 8.97 kHz but not on 137 kHz...

Mal, what ARGO settings do you use? QRSS-3, normal should be suitable. My DFCW was 4 seconds dot and 1 second break between the elements. I am using RIKs QRS program. Will switch to QRSS the next time (not only but sometimes ;-) ).

On sunday i have tested the IC-706 as a RX. For attenuation a had just the possibility to use the internal attenuator. But this is all still not working fine. I could not even receive OE5ODL. So i have to work on this side...

Has anyone a ready to use circuit for a homemade LF RX that uses a high power signal? LF RX means that i do not need an extra HF TRX to make signals audible. So the signal must be shifted down to the range where the soundcard is working or even to audible frequencies. And the input should be suitable for strong signals... :-)

73, es CU

Stefan/DK7FC


Am 27.09.2010 16:57, schrieb mal hamilton:
I see some confusion here as regards Earth antennas.
Is this antenna a wire x metres above ground and grounded at one end and fed with rf at the other ? if so then it is a grounded loop of some sort.
 
or
 
is it two long insulated wires lying on the ground and each wire grounded by a stake at one end and the other end pair fed with rf ?
 
Please be more clear about this type of antenna system.
 
I was able to see some DFCW signal broken up on Friday but no ID because the elements were too close together, more spacing between elements or QRS 10 and I could have got an ID
 
A missed opportunity for a DX report, the signal could have been DK7FC because of the QRG and QTR but this is NOT proof of signal.
I have a couple of screen shots as proof of a signal.
 
 
de G3KEV
 
----- Original Message -----
Sent: Saturday, September 25, 2010 12:28 PM
Subject: Fwd: Re: LF: DK7FC now on 137.715 in DFCW4 with his 600m earth antenna

---------- Forwarded message ----------
From: Stefan Schäfer <schaefer@iup.uni-heidelberg.de>
Date: 2010/9/24
Subject: Fwd: Re: LF: DK7FC now on 137.715 in DFCW4 with his 600m earth antenna
To: Roger Lapthorn <rogerlapthorn@gmail.com>


Hello Roger,

Below you find my eport on the todays LF earth antennas test. Currently it seems not possible for me to send to the reflector. I even do not get mails from there... (?)

Markus/DF6NM has forwarded the mail to the reflector but it wasn't reflected. Maybe, you can try to forward it? Can you tell me if it was reflected?

The mail contains some infos about my todays activity on VLF/LF! So could be interesting to some RX stations :-)

Best 73, Stefan/DK7FC

-------- Original-Nachricht --------
Betreff: Re: LF: DK7FC now on 137.715 in DFCW4 with his 600m earth antenna
Datum: Fri, 24 Sep 2010 22:02:59 +0200
Von: Stefan Schäfer <schaefer@iup.uni-heidelberg.de>
An: Renato Romero <contact@vlf.it>, Paul <paul@abelian.netcom.co.uk>


Hello Marco, Michel, John, LF,

This is a great day for the optimists, regarding EARTH ANTENNAs as a TX antenna! :-)

Until today i have not spend too much attention to my earth antenna as a TX antenna on LF. But knowing that my small PA for VLF (12V/300W class D) can also transmit on 137 kHz i gave it a first try today. I was almost sure that my signal will be visible on my grabber in 5 km distance but wasn't sure how the efficiency really is...

We know that the effective area of the formed loop must be smaller than on VLF but the big advantage seems to be that the antenna is even longer than lambda/4 for 2200m! Thus, to my surprise, and probably to the surprise of the most of you, the antenna seems to be very suitable as a TX antenna although the average height of the wire above ground is just about 4m!! The ground resistance is about 600 Ohm, currently.
I am VERY happy now to have a fixed antenna in a quiet location that does not matter of rain and wind or so and can be used from DC to HF :-)
A first transmission at 25 W was immediately visible on the DD7PC grabber, about 20 dB above noise in DFCW-3, distance is 77 km. So, it must have been audible!
A later transmission at 100 W is visible in France, with a good S/N. Many TNX to Michel and John! If the signal was 20 dB above noise in DFCW-3 at John's QTH in JN17VG (436 km), it must have been audible as well! :-)

Indeed, i have also never expected this efficiency from an earth antenna. It is months ago that i tried to convince some people here to try such an antenna. Maybe this day can help to convince practical oriented people that it is worth trying things that seems to be "wasted time" and/or "impossible" :-)))

I also hope that an earth antenna will be seen as an alternative to a normal closed loop or a vertical, especially in a woody region.

Attached you find a screenshot of my grabber and my signal in 5 km distance. Maybe it was 100 dB above noise? ;-)))

I still have no RX that can handle this big input signal. My 706 is not the best idea and i have most of my LF equipment on the parents QTH but i will try to receive tomorrow with the 706 and my PC on the earth antenna, using some attenuators and/or transformers. I will build a suitable RX for this antenna soon. But the QTH is EXCELLENT as you can image :-)

So, there was a discussion about the radiation pattern of an earth antenna, if it acts as a loop or not. Since the antenna length is in the region a lambda, it surely will not be a pure loop and will maybe have a preferred direction. YOU all can help to find out this radiation pattern by listening to my transmissions that will be done in the next days. Tomorrow, arround 8 UTC i will do a VLF test and later a LF test on the earth antenna. The VLF test is to reach Michael Oexner again and later on LF i would appreciate any rprts. But still not sure if i can come to QSO mode, due to the RX.

Now i know that this antenna is very worth to keep and improve. This will be done in the next weeks! :-)

BTW: I cannot transmit on sunday with the kite antenna, due to the WX, sri...

If some people want to try an earth antenna as a TX antenna, you can ask me any questions!

Sorry, i am a little euphoric now. The best sign if this happens during a project. Can it be wasted time then?


Best 73 and hope cuagn on LF this period!

Stefan/DK7FC




Am 24.09.2010 17:27, schrieb Michel Brunel: 
Hello Marco, LF,

Excellent copy here in JN18HP, hope the capture find its way through the
reflector. 
I was definitely not expecting such a signal with an earth electrode !

73

Michel - F5WK



  
Hello LF,
Stefan, DK7FC is transmitting with his 600m earth antenna on +/- 137.715KHz in DFCW4.
I could see him on my Grabber (see attachment)
http://www.qsl.net/dd7pc/lfgrabber_dd7pc.html and on the grabber from
Markus, DF6NM with a very good signal.
He was transmitting just with 25W and will increase now to 100W.
Any reports of his transmission are very welcome.
    
  
Vy73
Marco
DD7PC



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--------------070502010603030107020402--