Return-Path: X-Spam-DCC: paranoid 1356; 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=-2.0 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, 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 tAJCmA17004899 for ; Thu, 19 Nov 2015 13:48:10 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1ZzOad-0000xe-2m for rs_out_1@blacksheep.org; Thu, 19 Nov 2015 12:45:27 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1ZzOac-0000xV-O3 for rsgb_lf_group@blacksheep.org; Thu, 19 Nov 2015 12:45:26 +0000 Received: from mail-wm0-f51.google.com ([74.125.82.51]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES128-GCM-SHA256:128) (Exim 4.86) (envelope-from ) id 1ZzOZZ-000730-QU for rsgb_lf_group@blacksheep.org; Thu, 19 Nov 2015 12:45:25 +0000 Received: by wmec201 with SMTP id c201so23708799wme.0 for ; Thu, 19 Nov 2015 04:44:01 -0800 (PST) X-DKIM-Result: Domain=gmail.com Result=Good and Known Domain DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=Rl4nDIrBxhQgdW+hQ4Pgh+J7n7Kh3vOGOrxgi+rZM6c=; b=ignu07fcjN6IKuxXMTYgpjM4A0wOxZVhx77LuYQo6KooAS/7B4IplkUW6nFleM3EiZ 5RLqN9ei1ksswB2tvrXBmepTDq6L+mCHeFKeWrYpFGoUOahs9gimLpJXn3g+CKJpj0Uv nOUOsaEdcckleNbEgr/LSY+YLB9PYBQLf55BHsEha4iGSKT/TN96QhP4YEHP6eQduoUy QyCJEAsbUBAof0s3ypP0MqXzolbvS/cVmrN8WuAlaWK8lHo0/2mjLhen10XQf+PI35kP p4799UFXIBccH509L9Nj2rZgrigt1E9xuckYbOp5RGQecmDpcdpAXbaToKxSh6x5TS7y t+ZQ== MIME-Version: 1.0 X-Received: by 10.194.78.15 with SMTP id x15mr8023829wjw.144.1447937040888; Thu, 19 Nov 2015 04:44:00 -0800 (PST) Received: by 10.28.130.139 with HTTP; Thu, 19 Nov 2015 04:44:00 -0800 (PST) In-Reply-To: <1C735FA296594DF897C48882843B0EB7@gnat> References: <1729369062.20151119120030@chriswilson.tv> <1C735FA296594DF897C48882843B0EB7@gnat> Date: Thu, 19 Nov 2015 12:44:00 +0000 Message-ID: From: Andy Talbot To: rsgb_lf_group@blacksheep.org X-Scan-Signature: da9a90c67b7e22f6718c156d8d99c1a4 Subject: Re: LF: Re: Antenna relays Content-Type: multipart/alternative; boundary=047d7bfcfd7afabcac0524e41cd5 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: 5171 --047d7bfcfd7afabcac0524e41cd5 Content-Type: text/plain; charset=UTF-8 Alan - 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. 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. A knife switch on a ceramic former would probably work, otherwise find someone working for 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. >> >> >> >> -- >> >> >> Best regards, >> Chris 2E0ILY mailto:chris@chriswilson.tv >> >> >> > > --047d7bfcfd7afabcac0524e41cd5 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
Alan -=C2=A0
You're forgetting the loading coil ha= s to be switched out when using the loop at HF, so the relay has to withsta= nd the full RF voltage when using it as a vertical at LF/MF. =C2=A0=C2=A0

So you'll need a vacuum relay with a contacts r= ated at something like 10kV. The current will only be an amp or so. =C2=A0 = I tried this once using FR / Crydom reed relays that were certainly rated a= t that sort of voltage.=C2=A0 Trouble was that rating was DC.=C2=A0 At 137k= Hz it died with a flash from inside and melted contacts as soon as a decent= amount of RF was applied. =C2=A0=C2=A0

A knife sw= itch on a ceramic former would probably work, otherwise find someone workin= g for=C2=A0
NatGrid and try to get a 33 or 132kV contactor :-)


Andy =C2=A0G4JNT

=

On 19 November 20= 15 at 12:24, Alan Melia <alan.melia@btinternet.com> = wrote:
Hi Chris I dont think the relay ty= pe is too significant at these frequencies. The important thing is its cont= acts should be able to carry the current. It is at a low impedance point so= the voltages should not be excessive.=C2=A0 Even an open frame style inten= ded for switching 20 to 30A of 230v would be worth trying (I am sure you ha= ve a bin-full or two of those lying around :-))=C2=A0 ).......the old-timer= s used knife switches at these frequencies :-))

Alan
G3NYK

----- Original Message ----- From: "Chris Wilson" <chris@chriswilson.tv>=
To: <r= sgb_lf_group@blacksheep.org>
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=C2=A0 horizontal=C2=A0 quad=C2=A0 loop=C2=A0 as=C2=A0 the=C2=A0 vertical= for LF, the loop as the
capacitive=C2=A0 top hat. It means I am unable to use it for HF though. I a= m
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=C2=A0 line=C2=A0 with=C2=A0 the=C2=A0 bottom strapped together. the = other opens the
strap and connects the 2 legs to a balun and then my co as feed line.

Given=C2=A0 the voltages involved at LF, what sort of relay would I need to=
be looking at? Thanks.



--


Best regards,
Chris=C2=A0 2E0ILY=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=A0mailto:chris@chriswilson.tv





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