Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by klubnl.pl (8.14.4/8.14.4/Debian-8+deb8u2) with ESMTP id w15LEgiQ016235 for ; Mon, 5 Feb 2018 22:14:45 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1eio0a-00024D-Sz for rs_out_1@blacksheep.org; Mon, 05 Feb 2018 21:09:00 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1eio0Z-000244-Rx for rsgb_lf_group@blacksheep.org; Mon, 05 Feb 2018 21:08:59 +0000 Received: from smtp-out01.xworks.net ([31.25.48.13]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.89) (envelope-from ) id 1eio0W-0002UO-IE for rsgb_lf_group@blacksheep.org; Mon, 05 Feb 2018 21:08:58 +0000 Received: from mailbackend3 (cluster06.xworks.net [10.100.1.80]) by smtp-out01.xworks.net (Postfix) with ESMTP id C71B761956 for ; Mon, 5 Feb 2018 22:08:54 +0100 (CET) X-DKIM-Result: Domain=kabelmail.de Result=Signature OK DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kabelmail.de; s=mail; t=1517864934; bh=2Qi69YikV37uMkxOcnlT5u8+/8Oi5YpO/wqd8x41Jik=; h=Subject:To:References:From:Date:MIME-Version:In-Reply-To: Content-Type; b=UmoNHT3mtMyE5H/OSmNoGwa8essnhI4WSbb6SX00fWQDprm2+7NBJ4udvCQq/gnRf BuFlCXMxHxcKaGWUvc5jF/WEtoybCIgzGwXd3hD5pQj0FEt01TX2vtOSnA4qZrBRWZ Z0sb3yM/bXMc8jhyGqjmCShJIOgcxk9TW+IFQN6c= Received: from [192.168.36.33] (ipbcc12910.dynamic.kabel-deutschland.de [188.193.41.16]) (authenticated bits=0) by smtp.kabelmail.de with ESMTP id w15L8otQ010109 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Mon, 5 Feb 2018 22:08:51 +0100 X-mediaBEAM-Originating-IP: [188.193.41.16] X-mediaBEAM-AUTHID: [DK1IS@kabelmail.de] To: rsgb_lf_group@blacksheep.org References: <579355A36AEE9D4FA555C45D556003AB9AB49FE8@servigilant.vigilant.local> From: DK1IS Message-ID: Date: Mon, 5 Feb 2018 22:11:07 +0100 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: X-mediaBEAM-AuthCheck: route13 X-mediaBEAM-AuthScore: 0.0/5.0, scanned in 2.813sec X-Spam-Score: 0.0 (/) X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net", has NOT identified this incoming email as spam. The original message has been attached to this so you can view it or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: Hello Paul, thank you for your post! Enclosed please find my comments: Am 05.02.2018 um 10:35 schrieb Paul Nicholson: > Thank you Tom, that was a most interesting post with much food > for thought. > > Nice construction and good to see an alternative to air-cored > loading coils. The increase of inductance with current is > curious. An artifact of the test setup? [...] Content analysis details: (0.0 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- 0.0 HTML_MESSAGE BODY: HTML included in message 0.0 T_DKIM_INVALID DKIM-Signature header exists but is not valid X-Scan-Signature: a32b10ac5c14008078455df469dc45d3 Subject: Re: New station on VLF: DK1IS Content-Type: multipart/alternative; boundary="------------8A1F1AB1BE7C8537AE6F3211" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.0 required=5.0 tests=HTML_MESSAGE 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 This is a multi-part message in MIME format. --------------8A1F1AB1BE7C8537AE6F3211 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: quoted-printable X-MIME-Autoconverted: from 8bit to quoted-printable by smtp.kabelmail.de id w15L8otQ010109 Hello Paul, thank you for your post! Enclosed please find my comments: Am 05.02.2018 um 10:35 schrieb Paul Nicholson: > Thank you Tom, that was a most interesting post with much food > for thought. > > Nice construction and good to see an alternative to air-cored > loading coils.=C2=A0 The increase of inductance with current is > curious.=C2=A0 An artifact of the test setup? No, certainly not. Increasing the AC current from 0 to 600 mA in a=20 preliminary test with only two layers of inductors increased their=20 total=C2=A0 inductance degressively by 3.8 % with positive resp. 3,7 % wi= th=20 negative mutual coupling. Meanwhile Markus (DF6NM) told me he often saw=20 this: driving a ferrite inductor with DC decreases the inductance (as=20 well known) but driving it with AC first increases the inductance until=20 you go well into saturation when it decreases again. He explained it=20 with the different slope of the initial magnetisation curve at low vs.=20 medium drive levels, resulting in a more complanate hysteresis loop and=20 a lower inductance at low drive levels. Additional there is a minor=20 influence by the positive mutual coupling, rising more than proportional=20 with higher drive levels. > Interesting point > about the audio channels being out of phase. Having made the bad experience with the bridged mode I tested the stereo=20 mode with two identical input signals in phase opposition via a good=20 quality 4 windings audio transformer. No better result, that means at=20 least the problems don=C2=B4t come from the PAs internal inverter stage. = I=20 have to stay with one-channel stereo but that=C2=B4s ok. > Do you have any feedback from an E-field probe to stabilise > the phase? With the synthesizer exciter now in use it=C2=B4s impossible. Later on wi= th a=20 PC and appropriate software it could be done, but see your next item. > Perhaps that's not necessary with the relatively > low Q system. Losses do have their adventages ... > The antenna wires spaced one 1 metre - I assume 1 metre between > each wire. Yes, that=C2=B4s the situation - see picture below. > The 160 ohms antenna resistance, that must be > mostly ground resistance? Yes, it is. I measured the Marconi without loading coil against ground=20 at 8,27 kHz. C was 660 pF then, including the open antenna disconnection=20 switch. > > It=C2=B4s always a little bit frustrating that I can=C2=B4t hear my o= wn > > signal even at the VLF RX site at our club station DL0AO only > > 6 km away in a forest. > > Sometimes they become audible when a long transmission is > played back time compressed.=C2=A0=C2=A0 I tried that with your 28th > carrier but even with x20000 compression it was still not > audible. OK - meanwhile I=C2=B4m accustomed to it. > The ferrite chokes look a lot like RS components 715-6857, > which happen to be the same ones I use for filtering in > my 48V rx power supply.=C2=A0 10mH, Rdc =3D 3.394 Ohms. =C2=A0RS No.715-6857 is the 500 mA version - I=C2=B4m using the 600 mA v= ersion=20 715-6850 resp. Murata No. 1410606C. 73, Tom, DK1IS _*Marconi=C2=B4s end on a frosty winter morning:*_** ** --------------8A1F1AB1BE7C8537AE6F3211 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-MIME-Autoconverted: from 8bit to quoted-printable by smtp.kabelmail.de id w15L8otQ010109
Hello Paul,

thank you for your post! Enclosed please find my comments:

Am 05.02.2018 um 10:35 schrieb Paul Nicholson:
Thank you Tom, that was a most interesting post with much food
for thought.

Nice construction and good to see an alternative to air-cored
loading coils.=C2=A0 The increase of inductance with current is
curious.=C2=A0 An artifact of the test setup?

No, certainly not. Increasing the AC current from 0 to 600 mA in a preliminary test with only two layers of inductors increased their total=C2=A0 inductance degressively by 3.8 % with positive resp. 3,7 = % with negative mutual coupling. Meanwhile Markus (DF6NM) told me he often saw this: driving a ferrite inductor with DC decreases the inductance (as well known) but driving it with AC first increases the inductance until you go well into saturation when it decreases again. He explained it with the different slope of the initial magnetisation curve at low vs. medium drive levels, resulting in a more complanate hysteresis loop and a lower inductance at low drive levels. Additional there is a minor influence by the positive mutual coupling, rising more than proportional with higher drive levels.
=C2=A0
Interesting point
about the audio channels being out of phase.

Having made the bad experience with the bridged mode I tested the stereo mode with two identical input signals in phase opposition via a good quality 4 windings audio transformer. No better result, that means at least the problems don=C2=B4t come from the PAs internal inverter stage. I have to stay with one-channel stereo but that=C2=B4= s ok.

Do yo= u have any feedback from an E-field probe to stabilise
the phase?

With the synthesizer exciter now in use it=C2=B4s impossible. Later o= n with a PC and appropriate software it could be done, but see your next item.

Perhaps that's not necessary with the relatively
low Q system.

Losses do have their adventages ...

The antenna wires spaced one 1 metre - I assume 1 metre between
each wire.

Yes, that=C2=B4s the situation - see picture below.

The 160 ohms antenna resistance, that must be
mostly ground resistance?

Yes, it is. I measured the Marconi without loading coil against ground at 8,27 kHz. C was 660 pF then, including the open antenna disconnection switch.

> It=C2=B4s always a little bit frustrating that I can=C2=B4t hear my= own
> signal even at the VLF RX site at our club station DL0AO only
> 6 km away in a forest.

Sometimes they become audible when a long transmission is
played back time compressed.=C2=A0=C2=A0 I tried that with your 28t= h
carrier but even with x20000 compression it was still not
audible.

OK - meanwhile I=C2=B4m accustomed to it.

The ferrite chokes look a lot like RS components 715-6857,
which happen to be the same ones I use for filtering in
my 48V rx power supply.=C2=A0 10mH, Rdc =3D 3.394 Ohms.

=C2=A0RS No.715-6857 is the 500 mA version - I=C2=B4m using the 600 m= A version 715-6850 resp. Murata No. 1410606C.

73,
Tom, DK1IS

=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0 Marconi=C2=B4s end on a frost= y winter morning:=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=

3D""

--------------8A1F1AB1BE7C8537AE6F3211--