Return-Path: X-Spam-DCC: paranoid 1290; 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, FORGED_RCVD_HELO,HTML_30_40,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 u0VMLoIF031861 for ; Sun, 31 Jan 2016 23:21:50 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1aQ0JQ-0006r9-19 for rs_out_1@blacksheep.org; Sun, 31 Jan 2016 22:17:40 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1aQ0JP-0006r0-Le for rsgb_lf_group@blacksheep.org; Sun, 31 Jan 2016 22:17:39 +0000 Received: from rhcavuit02.kulnet.kuleuven.be ([134.58.240.130] helo=cavuit02.kulnet.kuleuven.be) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.86) (envelope-from ) id 1aQ0IV-0002Ae-9t for rsgb_lf_group@blacksheep.org; Sun, 31 Jan 2016 22:17:38 +0000 X-KULeuven-Envelope-From: rik.strobbe@fys.kuleuven.be X-KULeuven-Scanned: Found to be clean X-KULeuven-ID: 19644128083.A876C X-KULeuven-Information: Katholieke Universiteit Leuven Received: from icts-p-smtps-1.cc.kuleuven.be (icts-p-smtps-1e.kulnet.kuleuven.be [134.58.240.33]) by cavuit02.kulnet.kuleuven.be (Postfix) with ESMTP id 19644128083 for ; Sun, 31 Jan 2016 23:16:22 +0100 (CET) Received: from ICTS-S-HUB1.luna.kuleuven.be (icts-s-hub1.luna.kuleuven.be [10.112.9.15]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (No client certificate requested) by icts-p-smtps-1.cc.kuleuven.be (Postfix) with ESMTPS id 147BF403B for ; Sun, 31 Jan 2016 23:16:19 +0100 (CET) Received: from ICTS-S-MBX1.luna.kuleuven.be ([fe80::edaf:341f:90e:f70e]) by ICTS-S-HUB1.luna.kuleuven.be ([fe80::f5f7:d8cc:bee0:28d3%26]) with mapi id 14.03.0224.002; Sun, 31 Jan 2016 23:16:18 +0100 X-Kuleuven: This mail passed the K.U.Leuven mailcluster From: Rik Strobbe To: "rsgb_lf_group@blacksheep.org" Thread-Topic: LF: MF powerful Beacon in Poland? Thread-Index: AQHRWuGjQ6APKrgc8kqmWgQHtWACmJ8TBLUAgAAH2gCAAVPDgIABz1wW Date: Sun, 31 Jan 2016 22:16:17 +0000 Message-ID: <7E7DFBB4D102A04DB5ADC88D66628A4A444B56B4@ICTS-S-MBX1.luna.kuleuven.be> References: <8D328FCC12FD921-600-4E96AB@webmail-vm167.sysops.aol.com>,,<579355A36AEE9D4FA555C45D556003AB2533287C@servigilant.vigilant.local> In-Reply-To: <579355A36AEE9D4FA555C45D556003AB2533287C@servigilant.vigilant.local> Accept-Language: nl-BE, en-GB, en-US Content-Language: nl-BE X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.112.11.49] MIME-Version: 1.0 X-HELO-Warning: Remote host 134.58.240.130 (rhcavuit02.kulnet.kuleuven.be) used invalid HELO/EHLO cavuit02.kulnet.kuleuven.be - verification failed X-Scan-Signature: 80dfd4418e586cee7526d670ae10acbc Subject: RE: LF: MF powerful Beacon in Poland? Content-Type: multipart/alternative; boundary="_000_7E7DFBB4D102A04DB5ADC88D66628A4A444B56B4ICTSSMBX1lunaku_" 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: RO X-Status: X-Keywords: X-UID: 6593 --_000_7E7DFBB4D102A04DB5ADC88D66628A4A444B56B4ICTSSMBX1lunaku_ Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hello Richard, Luis, all, a horizontal dipole at low height (versus wavelength) is in theory an ineff= icient antenna. See http://www.strobbe.eu/on7yd/136ant/#HorDipole. But: 1. "Low height" is less than a few % of the wavelength. At 7% of the wavele= ngth the radiation resistance is already 10 Ohm. On 136kHz this 7% is an un= realistic 150m, on 475kHz it is "only" 44m! At a height of 100m (as suggest= ed by Richard) the radiation resistance on 475kHz will rise to 40 Ohm! 2. The better (more conductive) the soil the worse a low horizontal dipole = will be. Or the other way arround: the worse the soil the better the antenn= a! So in certain conditions a horizontal dipole at a height of 20m or more = might be working pretty well on 475kHz. As often there is only one way to know: try it ;-) 73, Rik ON7YD - OR7T ________________________________ Van: owner-rsgb_lf_group@blacksheep.org [owner-rsgb_lf_group@blacksheep.org= ] namens VIGILANT Luis Fern=E1ndez [luis@vigilant.es] Verzonden: zaterdag 30 januari 2016 20:21 Aan: rsgb_lf_group@blacksheep.org Onderwerp: Re: LF: MF powerful Beacon in Poland? Hi Richard I'm probably the only one in MF transmitting with an antenna installed in a= 80m high building (26 floors) By Benidorm standars this is also a small tower. But I'm lucky to have acce= ss to top terrace to grow my antenna farm ;-) I agree with the rest. Any beacon signal is wellcome and useful. CW, QRSS o= r digital all counts and helps to increase activity and rise the interest of other hams >I live in a 15 floor building, on top of which there is a 30 meter mast, a= nd my building - by Warsaw >standards - is "small". (I set a QRP world reco= rd in 2005 from such a building on 3.5mhz) Do you have access to this 30m mast ? Would it be possible to hang a vertic= al slope wire from top of the mast to top terrace on floor 15th ? >Thus to hang a dipole on such a building would not be expensive and to mou= nt a 1w TX at the dipole >center point would make beacon construction simpl= e. A dipole is not an option on MF. If the power limitation is 1w radiated pow= er, you will have to use many watts on Tx to get 1w radiated, specially with a low efficient antenna What I'm using here with great success is a 11m vertical with two 6m "arms"= as top load Then in the base of the antenna a coil about 3mH to get it in resonance. Th= e ground line of PA runs to ground using a water pipe inside the building. This is not "ground"= but the extension of the vertical antenna. So the antena is really a vertical formed by 80m + f= eed + coil + 11m + topload If you build something similar at your building tower it should provide sim= ilar results My QRP tests ended by injecting 1mW to the antenna and then I got my signal= decoded using Opera32 at 300Km by EB3FRN. All this on 630m band Your mileage may vary ....as US guys say ;-) 73 de Luis EA5DOM --_000_7E7DFBB4D102A04DB5ADC88D66628A4A444B56B4ICTSSMBX1lunaku_ Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Hello Richard, Luis, all,

 

a horizontal dipole at low height (versus wavelength) is in theory = an inefficient antenna. See http://www.strobb= e.eu/on7yd/136ant/#HorDipole.

But:

1. "Low height" is less than a few % of the wavelength. At 7% = of the wavelength the radiation resistance is already 10 Ohm. On 136kHz thi= s 7% is an unrealistic 150m, on 475kHz it is "only" 44m! At a hei= ght of 100m (as suggested by Richard) the radiation resistance on 475kHz will rise to 40 Ohm!

2. The better (more conductive) the soil the worse a low horizontal dipo= le will be. Or the other way arround: the worse the soil the better the ant= enna! So in certain conditions a horizontal dipole at a height of 20m or mo= re might be working pretty well on 475kHz.

 

As often there is only one way to know: try it ;-)

 

73, Rik  ON7YD - OR7T

 

Van: owner-rsgb_lf_group@blacksheep.org [o= wner-rsgb_lf_group@blacksheep.org] namens VIGILANT Luis Fern=E1ndez [luis@v= igilant.es]
Verzonden: zaterdag 30 januari 2016 20:21
Aan: rsgb_lf_group@blacksheep.org
Onderwerp: Re: LF: MF powerful Beacon in Poland?

Hi Richard

I'm probably the only one in MF transmitting with an antenna installed= in a 80m high building (26 floors)
By Benidorm standars this is also a small tower. But I'm lucky to have= access to top terrace to grow my
antenna farm ;-)

I agree with the rest. Any beacon signal is wellcome and useful. CW, Q= RSS or digital all counts
and helps to increase activity and rise the interest of other hams

>I live in a 15 floor building, on top of which there is a 30 meter= mast, and my building - by Warsaw >standards - is "small". (I= set a QRP world record in 2005 from such a building on 3.5mhz)

Do you have access to this 30m mast ? Would it be possible to hang a v= ertical slope wire from top
of the mast to top terrace on floor 15th ?

>Thus to hang a dipole on such a building would not be expensive and to = mount a 1w TX at the dipole >center point would make beacon construction= simple.

A dipole is not an option on MF. If the power limitation is 1w radiate= d power, you will have to use
many watts on Tx to get 1w radiated, specially with a low efficient an= tenna

What I'm using here with great success is a 11m vertical with two 6m &= quot;arms" as top load
Then in the base of the antenna a coil about 3mH to get it in resonanc= e. The ground line of PA
runs to ground using a water pipe inside the building. This is not &qu= ot;ground" but the extension of
the vertical antenna. So the antena is really a vertical formed by &nb= sp;80m + feed + coil + 11m + topload

If you build something similar at your building tower it should provid= e similar results

My QRP tests ended by injecting 1mW to the antenna and then I got my s= ignal decoded using
Opera32 at 300Km by EB3FRN. All this on 630m band

Your mileage may vary ....as US guys say ;-)

73 de Luis
EA5DOM



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