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 x13HPaAo027832 for ; Sun, 3 Feb 2019 18:25:42 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1gqLRp-0002lc-BA for rs_out_1@blacksheep.org; Sun, 03 Feb 2019 17:20:49 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1gqLRi-0002lT-5E for rsgb_lf_group@blacksheep.org; Sun, 03 Feb 2019 17:20:42 +0000 Received: from resqmta-ch2-04v.sys.comcast.net ([2001:558:fe21:29:69:252:207:36]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.91) (envelope-from ) id 1gqLRf-0005Tt-7m for rsgb_lf_group@blacksheep.org; Sun, 03 Feb 2019 17:20:40 +0000 Received: from resomta-ch2-16v.sys.comcast.net ([69.252.207.112]) by resqmta-ch2-04v.sys.comcast.net with ESMTP id qL2UgR0UcJyAtqLRbgi1xH; Sun, 03 Feb 2019 17:20:35 +0000 X-DKIM-Result: Domain=comcast.net Result=Signature OK DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=comcast.net; s=q20161114; t=1549214435; bh=LR+kwpVLwsrcz9ebcT5HsN70IBtwzIP7u2FieQNe5Tk=; h=Received:Received:From:To:Subject:Date:Message-ID:MIME-Version: Content-Type; b=A4qTk7B9e/zewczoMsxdPeu9WNScQFWSeLMx0IJkGF/+vkLyyj6kVCbOHOfWC2KXr WPl9GE3gLUUyzYBlKl/jDDT5kxUUCuvK+REauXFf8wEb0IDXVJi6MK5ZfugIdElN0e d+f/stmH2MyxSDhyqVw7z/w5TNUW8tSesqIoJfF4Ptae9xpn+5L0uq3nKZOzmBLHYs OuUBjqDj/TQ58Ah3Im9nJrn7rLulmgH/5jMg2D4wxGVuq/30CL+NzK4l902KODUAUT J/B+B/EXzd+ny7yT2QxlW8B4KWYBb7bYdYmjoIug7B30cSVLx0BakHpMC3WJszsvtx oG9o7jepsHn8A== Received: from Owner ([IPv6:2601:140:8500:7f9f:78f6:dd:b547:d008]) by resomta-ch2-16v.sys.comcast.net with ESMTPA id qLRYgJRJncxRXqLRZg0Yeh; Sun, 03 Feb 2019 17:20:35 +0000 X-Xfinity-VMeta: sc=0;st=legit From: To: References: <168a5557287.marcocadeddu@tin.it> In-Reply-To: <168a5557287.marcocadeddu@tin.it> Date: Sun, 3 Feb 2019 12:20:24 -0500 Message-ID: <011f01d4bbe4$c5518a60$4ff49f20$@comcast.net> MIME-Version: 1.0 X-Mailer: Microsoft Outlook 14.0 Thread-Index: AQKPRZo0w5ysJ6HDslazyA2Tl4NEhqRZNzpA Content-Language: en-us X-Spam-Score: 0.3 (/) 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: Thanks Marco, I added the 940C to my list. I don’t know if the ESRs in the 940C data sheet are specified at 120 Hz or 1 kHz, but in any case the 940C ESR and other specifications look good. Content analysis details: (0.3 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.7 RCVD_IN_DNSWL_LOW RBL: Sender listed at http://www.dnswl.org/, low trust [2001:558:fe21:29:69:252:207:36 listed in] [list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (hvanesce[at]comcast.net) 0.0 HTML_MESSAGE BODY: HTML included in message 1.0 FREEMAIL_REPLY From and body contain different freemails X-Scan-Signature: efe129b020ea1a79323c9787966dda85 Subject: RE: RE: LF: TXing on indoor/outdoor loops and Silver mica caps Content-Type: multipart/alternative; boundary="----=_NextPart_000_0120_01D4BBBA.DC7DCC50" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.5 required=5.0 tests=HTML_50_60,HTML_MESSAGE, NO_REAL_NAME 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 multipart message in MIME format. ------=_NextPart_000_0120_01D4BBBA.DC7DCC50 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Thanks Marco, =20 I added the 940C to my list. =20 =20 I don=E2=80=99t know if the ESRs in the 940C data sheet are specified at = 120 Hz or 1 kHz, but in any case the 940C ESR and other specifications = look good. =20 Looking at the 940C package brings to mind that I have been = series/parallel stacking the rectangular PHE450 capacitors incorrectly: = no air gap for cooling. I wonder if a stack of 940Cs would be better = than rectangular capacitors (PHE450 etc.) in a forced-air configuration. = Or in de-ionized ice water as Stefan mentioned. =20 73, =20 Jim AA5BW =20 =20 From: owner-rsgb_lf_group@blacksheep.org = [mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of = marcocadeddu@tin.it Sent: Thursday, January 31, 2019 2:14 PM To: rsgb_lf_group@blacksheep.org Subject: R: RE: LF: TXing on indoor/outdoor loops and Silver mica caps =20 Hi Jim, just to share my feelings / thoughs ... Since I started to play with LF I collected a number of R.I.P. caps ;-) = and failure reason, on my opinion, was that the current was exceeding = the capability of the cap. I was used to refer to the insulation voltage and thus seen the = trepassing of a lot of caps, the found this serie=20 http://www.cde.com/resources/catalogs/940C.pdf and never had further trespassing at least in low impedance, relative = high power: for instance for the caps insulating the dc component and = carrying the RF power from a 500W pushpull @28Vdc. For other similar application like for instance the caps in the output = LC of Decca style PA or Class E PA I used succesfully either the above = CDE caps or WIMA FKP1 combining series /parallel in order to have the = wished capacitance / voltage insulation and current capability. I guess should be nice organize a day to remember all our ex-devices ;-) 73, Marco IK1HSS ----Messaggio originale---- Da: hvanesce@comcast.net Data: 31-gen-2019 18.55 A: Ogg: RE: LF: TXing on indoor/outdoor loops and Silver mica caps =20 I have been using what appear to be similar polypropylene capacitors = [data sheet specifications (see below) including spectral loss tangent = seem very similar] for multi-turn indoor and outdoor (35 meter x 35 = meter) single-turn VLF transmitting loops for about five years (when = time is available) and have found the following: 1) Temperature rise has been roughly consistent with the spectral loss = tangent table 2) No change noticed in capacitance after approximately 200 of hours of = transmitter operation at capacitor case temperature of 115 F (46 C) =20 Used 80-PHE450HD6470JR6L2 (0.47 uF) and also used 0.1 uF through 1.0 uF = from the same PHE450 product line; always series/parallel stacking = capacitors of the same value to enable higher current and/or voltage at = a given capacitance. =20 Data sheet: https://www.mouser.com/datasheet/2/212/KEM_F3033_PHE450-1104182.pdf =20 Reached somewhat of a practical limit of series/parallel stacking of = these capacitors, for indoor multi-turn loops from 1 meter diameter to = ten square meters, and outdoor loop 35 m x 35 m; and have hoped to find = capacitors that would allow more current and voltage. I thought I had = investigated (through calculations, not on the workbench) silver micas = and found these polypropylene capacitors to be better based on = calculations, but based on the messages between Stefan, Dimitris and = Marko I must have missed something (perhaps temperature rating?); thanks = for the inputs on this topic; looking forward to silver micas. =20 73, =20 Jim AA5BW =20 =20 From: owner-rsgb_lf_group@blacksheep.org = [mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of dhchurch Sent: Thursday, January 31, 2019 5:55 AM To: RSGB LF group Subject: Re: Re: LF: TXing WSPR/MF on an indoor loop, part 2 =20 Hello Dimitrios =20 Polypropylene capacitors can actually self-heal to such an extent that = there's little left of them. The melting point of polypropylene is not = very high and they can end up as just a liitle blob of plastic.=20 =20 Don't worry though, I still use them suitably rated for the frequency in = use and most of them are 600Vac or more. =20 73, Hugh, M0DSZ ----- Receiving the following content -----=20 From: Dimitrios Tsifakis =20 Receiver: rsgb_lf_group =20 Time: 2019-01-31, 00:25:55 Subject: Re: LF: TXing WSPR/MF on an indoor loop, part 2 =20 Hi Stefan, In my experience these polypropylene capacitors when they fail, they just lose some capacitance. I think they call it 'self healing', maybe they imply that when they fail there is no short circuit? I have some really nice silver mica capacitors (ex MW broadcast stuff) that would be perfect for this task... Anyway, I am slowly gearing up for some VLF action over here. The other day I did some tests at 16.72 kHz into an ugly loop (very roughly 120 metres by 3 metres, single turn) and I was able to receive my signals using an unoptimise ferrite antenna at a bit over 2 km from the TX. I don't think I am in the near field at that distance, am I? :-) 73, Dimitris VK2COW > =20 ------=_NextPart_000_0120_01D4BBBA.DC7DCC50 Content-Type: text/html; charset="utf-8" Content-Transfer-Encoding: quoted-printable

Thanks Marco,

 

I added the 940C to my list.=C2=A0

 

I don=E2=80=99t know if the ESRs in the 940C data sheet are specified = at 120 Hz or 1 kHz, but in any case the 940C ESR and other = specifications look good.

 

Looking at the 940C package brings to mind that I have been = series/parallel stacking the rectangular PHE450 capacitors incorrectly: no air gap for cooling. I wonder if a = stack of 940Cs would be better than rectangular capacitors (PHE450 etc.) = in a forced-air configuration. Or in de-ionized ice water as Stefan = mentioned.

 

73,

 

Jim AA5BW =C2=A0=C2=A0=C2=A0=C2=A0

 

From:= = owner-rsgb_lf_group@blacksheep.org = [mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of = marcocadeddu@tin.it
Sent: Thursday, January 31, 2019 2:14 = PM
To: rsgb_lf_group@blacksheep.org
Subject: R: RE: = LF: TXing on indoor/outdoor loops and Silver mica = caps

 

Hi Jim,
just to = share my feelings / thoughs ...
Since I started to play with LF I = collected a number of R.I.P. caps ;-) and failure reason, on my opinion, = was that the current was exceeding the capability of the cap.
I was = used to refer to the insulation voltage and thus seen the trepassing of = a lot of caps, the found this serie

http://www.cde.co= m/resources/catalogs/940C.pdf

and never had further = trespassing at least in low impedance, relative high power: for instance = for the caps insulating the dc component and carrying the RF power from = a 500W pushpull @28Vdc.
For other similar application like for = instance the caps in the output LC of Decca style PA or Class E PA I = used succesfully either the above CDE caps or WIMA FKP1 combining series = /parallel in order to have the wished capacitance / voltage insulation = and current capability.

I guess should be nice organize a day to = remember all our ex-devices ;-)

73, Marco = IK1HSS


----Messaggio originale----
Da: hvanesce@comcast.net
Data: = 31-gen-2019 18.55
A: <rsgb_lf_group@blacksheep.org= >
Ogg: RE: LF: TXing on indoor/outdoor loops and Silver mica = caps

 

I have been using what appear to be similar polypropylene capacitors = [data sheet specifications (see below) including spectral loss tangent = seem very similar] for multi-turn indoor and outdoor (35 meter x 35 = meter) single-turn VLF transmitting loops for about five years (when = time is available) and have found the following:

1) Temperature rise has been roughly consistent with the spectral = loss tangent table

2) No change noticed in capacitance after approximately 200 of hours = of transmitter operation at capacitor case temperature of 115 F (46 = C)

 

Used 80-PHE450HD6470JR6L2 (0.47 uF) and also used 0.1 uF through 1.0 = uF from the same PHE450 product line; always series/parallel stacking = capacitors of the same value to enable higher current and/or voltage at = a given capacitance.

 

Data sheet:

https://www.mouser.com/datasheet/2/212/KEM_F3033_PHE450-1104182.pdf

 

Reached somewhat of a practical limit of series/parallel stacking of = these capacitors, for indoor multi-turn loops from 1 meter diameter to = ten square meters, and outdoor loop 35 m x 35 m; and have hoped to find = capacitors that would allow more current and voltage. I thought I had = investigated (through calculations, not on the workbench) silver micas = and found these polypropylene capacitors to be better based on = calculations, but based on the messages between Stefan, Dimitris and = Marko I must have missed something (perhaps temperature rating?); thanks = for the inputs on this topic; looking forward to silver = micas.

 

73,

 

Jim AA5BW =        

 

From:= = owner-rsgb_lf_group@bl= acksheep.org [mailto:owner-rsgb_lf_g= roup@blacksheep.org] On Behalf Of dhchurch
Sent: = Thursday, January 31, 2019 5:55 AM
To: RSGB LF = group
Subject: Re: Re: LF: TXing WSPR/MF on an indoor loop, = part 2

 <= /o:p>

Hello = Dimitrios

 =

Polypropylene= capacitors can actually self-heal to such an extent that there's little = left of them. The melting point of polypropylene is not very = high and they can end up as just a liitle blob of = plastic. 

 =

Don't worry = though, I still use them suitably rated for the frequency in use and = most of them are 600Vac or more.

 =

73, Hugh, = M0DSZ

----- = Receiving the following content ----- =

From:<= /b> Dimitrios Tsifakis =

Receiver: rsgb_lf_group =

Time:<= /b> = 2019-01-31, 00:25:55

Subject: = Re: LF: TXing WSPR/MF on an indoor loop, part = 2

 =

Hi = Stefan,

In my experience these polypropylene capacitors when they = fail, they
just lose some capacitance. I think they call it 'self = healing', maybe
they imply that when they fail there is no short = circuit?

I have some really nice silver mica capacitors (ex MW = broadcast stuff)
that would be perfect for this = task...

Anyway, I am slowly gearing up for some VLF action over = here. The
other day I did some tests at 16.72 kHz into an ugly loop = (very
roughly 120 metres by 3 metres, single turn) and I was able to = receive
my signals using an unoptimise ferrite antenna at a bit over = 2 km from
the TX. I don't think I am in the near field at that = distance, am I?
:-)

73, Dimitris = VK2COW

>

 

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