Return-Path: Received: (qmail 28251 invoked from network); 14 Mar 2001 08:48:54 -0000 Received: from unknown (HELO murphys-inbound.servers.plus.net) (212.159.14.225) by 10.226.25.101 with SMTP; 14 Mar 2001 08:48:54 -0000 Received: (qmail 26970 invoked from network); 14 Mar 2001 08:48:55 -0000 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by murphys with SMTP; 14 Mar 2001 08:48:55 -0000 Received: from majordom by post.thorcom.com with local (Exim 3.16 #2) id 14d6rK-00020R-00 for rsgb_lf_group-outgoing@blacksheep.org; Wed, 14 Mar 2001 08:42:18 +0000 Received: from amersham.mail.uk.easynet.net ([195.40.1.45]) by post.thorcom.com with esmtp (Exim 3.16 #2) id 14d6rI-00020M-00 for rsgb_lf_group@blacksheep.org; Wed, 14 Mar 2001 08:42:16 +0000 Received: from ericadodd (tnt-13-97.easynet.co.uk [212.134.22.97]) by amersham.mail.uk.easynet.net (Postfix) with SMTP id B851717482 for ; Wed, 14 Mar 2001 08:41:53 +0000 (GMT) Message-ID: <000f01c0ac63$4bda2060$611686d4@ericadodd> From: "g3ldo" To: rsgb_lf_group@blacksheep.org References: <005201c0abf2$2e992e40$3025ff3e@oemcomputer> Subject: LF: Re: Valves Date: Wed, 14 Mar 2001 08:45:31 -0000 MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1; format=flowed Content-Transfer-Encoding: 8bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.50.4522.1200 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Sender: Paul, G4MD, said > Subject thread is heading back towards my territory! Same here - showing my age! > > The silver EF50's were service issue valves - VR91 for the RAF, ARP12 for > the army. I suppose the navy must have had them as well, but I don't recall > the designation....Red ones were the civilian issue. > I'm sure I recall my late father saying the H2S set had over 100 of them, > and it was unknown for them all to be working simultaneously! I worked on H2S Radar when I was in the RAF but I can't remember there being 100 VR91s used. The equipment had a wide band 45MHz IF strip with about 8 or 9 red VR91s. Much sought after from the ex-govnt radio stores as home-brew TV receivers for receiving Alexander Palace. H2S Mk 3G and H2S Mk4A were quite reliable considering their complexity. The greatest cause of faults was the Pye plugs used for coaxial cable inter unit connections. The ARP12 is a directly heated pentode used in battery operated Army pack sets. The E88CC is a double triode frame grid valve that was used in UHF TV tuners, designed to overcome the space charge effect at these frequencies. They were used until superior solid state devices came along. At the Amberley Museum we have 1000s of these valves! Regards, Peter, G3LDO e-mail Web