Return-Path: X-Spam-DCC: paranoid 1181; 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=2.2 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, FORGED_MUA_OUTLOOK,HTML_40_50,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 tAJDnJBh005114 for ; Thu, 19 Nov 2015 14:49:19 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1ZzPUv-0001CW-4K for rs_out_1@blacksheep.org; Thu, 19 Nov 2015 13:43:37 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1ZzPUu-0001CN-P3 for rsgb_lf_group@blacksheep.org; Thu, 19 Nov 2015 13:43:36 +0000 Received: from rgout0507.bt.lon5.cpcloud.co.uk ([65.20.0.228]) by relay1.thorcom.net with esmtp (Exim 4.86) (envelope-from ) id 1ZzPTq-0007KF-Fn for rsgb_lf_group@blacksheep.org; Thu, 19 Nov 2015 13:43:35 +0000 X-OWM-Source-IP: 81.151.235.203 (GB) X-OWM-Env-Sender: alan.melia@btinternet.com X-CTCH-RefID: str=0001.0A090202.564DD1B2.00F1,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0 X-Junkmail-Premium-Raw: score=39/50,refid=2.7.2:2015.11.19.115715:17:39.532,ip=81.151.235.203,rules=__HAS_MSGID, __SANE_MSGID, MSGID_32HEX_LC, INVALID_MSGID_NO_FQDN, __MSGID_32HEX, __HAS_FROM, __PHISH_FROM2, __FRAUD_WEBMAIL_FROM, __TO_MALFORMED_2, __TO_NO_NAME, __REFERENCES, __BOUNCE_CHALLENGE_SUBJ, __BOUNCE_NDR_SUBJ_EXEMPT, __SUBJ_ALPHA_END, __MIME_VERSION, __CT, __CTYPE_MULTIPART_ALT, __CTYPE_HAS_BOUNDARY, __CTYPE_MULTIPART, __HAS_X_PRIORITY, __HAS_MSMAIL_PRI, __HAS_X_MAILER, USER_AGENT_OE, __OUTLOOK_MUA_1, __USER_AGENT_MS_GENERIC, __ANY_URI, __FRAUD_BODY_WEBMAIL, __URI_NO_WWW, __URI_NO_PATH, __SUBJ_ALPHA_NEGATE, __INT_PROD_TV, SUPERLONG_LINE, __HTML_AHREF_TAG, __HAS_HTML, HTML_NO_HTTP, BODYTEXTP_SIZE_3000_LESS, BODYTEXTH_SIZE_10000_LESS, __MIME_HTML, __TAG_EXISTS_HTML, RDNS_GENERIC_POOLED, __URI_NS, SXL_IP_DYNAMIC[203.235.151.81.fur], RDNS_SUSP_GENERIC, __PHISH_FROM, __OUTLOOK_MUA, RDNS_SUSP, __FRAUD_WEBMAIL, FORGED_MUA_OUTLOOK, REFERENCES, NO_URI_HTTPS X-CTCH-Spam: Unknown Received: from gnat (81.151.235.203) by rgout05.bt.lon5.cpcloud.co.uk (8.6.122.06) (authenticated as alan.melia@btinternet.com) id 564ADD660049073F for rsgb_lf_group@blacksheep.org; Thu, 19 Nov 2015 13:42:00 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=btinternet.com; s=btcpcloud; t=1447940540; bh=cB92eDJ1o7jtxfWW7lHOqPBA3VPLT/+cWM9VwexeTgk=; h=Message-ID:From:To:References:Subject:Date:MIME-Version:X-Mailer; b=GuiJR/KB9LTUWsPsC1l4ttTI6BbDHF0frbFp4tw7fNx8DfLVBSOp5RPTzt2NwpP5WgggC1oiyDN5aj8PjkMj0LOZIupJ7pSTS6PNW9ZaNgN5MiMvif6aa+XoPLSOCDVODV/vsBKJaS9PB8Sxf0dc658BbKGGOKS8DkR7QBw8nyA= Message-ID: <85DEAEE9B22C448CAB7794EAA388CF23@gnat> From: "Alan Melia" To: References: <1729369062.20151119120030@chriswilson.tv><1C735FA296594DF897C48882843B0EB7@gnat> Date: Thu, 19 Nov 2015 13:42:07 -0000 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5931 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.6157 X-Scan-Signature: 974e9bcd09e4f3403f97af2f38f8fb73 Subject: Re: LF: Re: Antenna relays Content-Type: multipart/alternative; boundary="----=_NextPart_000_004F_01D122D0.156A3940" 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: 5172 This is a multi-part message in MIME format. ------=_NextPart_000_004F_01D122D0.156A3940 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Hi Andy Surely the voltage will not appear across the contacts, though I agree = contacts to activating coil might be a problem. Yes reeds area problem because I think of the reed material. I only used = them (from Coto) at low levels on ATE. I did have some rated in the kV = range but not taking much current. Alan G3NYK ----- Original Message -----=20 From: Andy Talbot=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Thursday, November 19, 2015 12:44 PM Subject: Re: LF: Re: Antenna relays Alan -=20 You're forgetting the loading coil has to be switched out when using = the loop at HF, so the relay has to withstand the full RF voltage when = using it as a vertical at LF/MF. =20 So you'll need a vacuum relay with a contacts rated at something like = 10kV. The current will only be an amp or so. I tried this once using = FR / Crydom reed relays that were certainly rated at that sort of = voltage. Trouble was that rating was DC. At 137kHz it died with a = flash from inside and melted contacts as soon as a decent amount of RF = was applied. =20 A knife switch on a ceramic former would probably work, otherwise find = someone working for=20 NatGrid and try to get a 33 or 132kV contactor :-) Andy G4JNT On 19 November 2015 at 12:24, Alan Melia = wrote: Hi Chris I dont think the relay type is too significant at these = frequencies. The important thing is its contacts should be able to carry = the current. It is at a low impedance point so the voltages should not = be excessive. Even an open frame style intended for switching 20 to 30A = of 230v would be worth trying (I am sure you have a bin-full or two of = those lying around :-)) ).......the old-timers used knife switches at = these frequencies :-)) Alan G3NYK ----- Original Message ----- From: "Chris Wilson" = To: Sent: Thursday, November 19, 2015 12:00 PM Subject: LF: Antenna relays 19 November 2015 I am currently running a bottom strapped windowed ladder line = feeder to my horizontal quad loop as the vertical for LF, the loop as = the capacitive top hat. It means I am unable to use it for HF though. = I am wondering if I might add a remote switched relay at the bottom of = the ladder line, so it has two states. One connects my co ax feeder to = the ladder line with the bottom strapped together. the other opens = the strap and connects the 2 legs to a balun and then my co as feed = line. Given the voltages involved at LF, what sort of relay would I = need to be looking at? Thanks. --=20 Best regards, Chris 2E0ILY = mailto:chris@chriswilson.tv ------=_NextPart_000_004F_01D122D0.156A3940 Content-Type: text/html; charset="utf-8" Content-Transfer-Encoding: quoted-printable =EF=BB=BF
Hi Andy
Surely the voltage will not appear = across the=20 contacts, though I agree contacts to activating coil might be a=20 problem.
 
Yes reeds area problem because I think = of the reed=20 material. I only used them (from Coto) at low levels on ATE.  I did = have=20 some rated in the kV range but not taking much current.
 
Alan
G3NYK
----- Original Message -----
From:=20 Andy=20 Talbot
Sent: Thursday, November 19, = 2015 12:44=20 PM
Subject: Re: LF: Re: Antenna = relays

Alan - 
You're forgetting the loading coil has to be switched out when = using the=20 loop at HF, so the relay has to withstand the full RF voltage when = using it as=20 a vertical at LF/MF.   

So you'll need a vacuum relay with a contacts rated at something = like=20 10kV. The current will only be an amp or so.   I tried this once = using FR=20 / Crydom reed relays that were certainly rated at that sort of = voltage. =20 Trouble was that rating was DC.  At 137kHz it died with a flash = from=20 inside and melted contacts as soon as a decent amount of RF was = applied.=20   

A knife switch on a ceramic former would probably work, otherwise = find=20 someone working for 
NatGrid and try to get a 33 or 132kV contactor :-)


Andy  G4JNT


On 19 November 2015 at 12:24, Alan Melia = <alan.melia@btinternet.com> wrote:
Hi Chris I dont think the relay type is too = significant at=20 these frequencies. The important thing is its contacts should be = able to=20 carry the current. It is at a low impedance point so the voltages = should not=20 be excessive.  Even an open frame style intended for switching = 20 to=20 30A of 230v would be worth trying (I am sure you have a bin-full or = two of=20 those lying around :-))  ).......the old-timers used knife = switches at=20 these frequencies :-))

Alan
G3NYK

----- Original = Message=20 ----- From: "Chris Wilson" <chris@chriswilson.tv>
To: <rsgb_lf_group@blacksheep.org>
Sent: = Thursday,=20 November 19, 2015 12:00 PM
Subject: LF: Antenna = relays


19 November 2015


I am currently = running a=20 bottom strapped windowed ladder line feeder to
my =20 horizontal  quad  loop  as  the  vertical = for LF,=20 the loop as the
capacitive  top hat. It means I am unable = to use=20 it for HF though. I am
wondering if I might add a remote = switched relay=20 at the bottom of the
ladder line, so it has two states. One = connects my=20 co ax feeder to the
ladder  line  with  = the  bottom=20 strapped together. the other opens the
strap and connects the 2 = legs to=20 a balun and then my co as feed line.

Given  the = voltages=20 involved at LF, what sort of relay would I need to
be looking = at?=20 Thanks.



--=20


Best regards,
Chris  2E0ILY    =    =20                  =20  mailto:chris@chriswilson.tv





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