Return-Path: Received: (qmail 5968 invoked from network); 13 Mar 2001 09:14:16 -0000 Received: from unknown (HELO murphys-inbound.servers.plus.net) (212.159.14.225) by 10.226.25.101 with SMTP; 13 Mar 2001 09:14:16 -0000 Received: (qmail 25502 invoked from network); 13 Mar 2001 09:14:15 -0000 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by murphys with SMTP; 13 Mar 2001 09:14:15 -0000 Content-Transfer-Encoding: 8bit Received: from majordom by post.thorcom.com with local (Exim 3.16 #2) id 14ckfb-00036l-00 for rsgb_lf_group-outgoing@blacksheep.org; Tue, 13 Mar 2001 09:00:43 +0000 Received: from bob.dera.gov.uk ([192.5.29.90]) by post.thorcom.com with esmtp (Exim 3.16 #2) id 14ckfa-00036g-00 for rsgb_lf_group@blacksheep.org; Tue, 13 Mar 2001 09:00:42 +0000 X-Priority: 3 X-MSMail-Priority: Normal Received: by bob.dera.gov.uk; (8.8.8/1.3/10May95) id JAA30309; Tue, 13 Mar 2001 09:02:52 GMT Received: (qmail 19137 invoked from network); 13 Mar 2001 09:51:52 -0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Received: from gauntlet.mail.dera.gov.uk (172.16.9.10) by baton.dera.gov.uk with SMTP; 13 Mar 2001 09:51:52 -0000 Received: by gauntlet.mail.dera.gov.uk; id JAA24367; Tue, 13 Mar 2001 09:39:16 GMT Received: from unknown(10.71.64.31) by gauntlet.mail.dera.gov.uk via smap (3.2) id xma024085; Tue, 13 Mar 01 09:38:26 GMT Received: from FRN-MAIL-3.dera.gov.uk (unverified) by mailguard.dera.gov.uk (Content Technologies SMTPRS 4.1.5) with ESMTP id for ; Tue, 13 Mar 2001 09:04:40 +0000 Received: by frn-mail-3.dera.gov.uk with Internet Mail Service (5.5.2650.21) id ; Tue, 13 Mar 2001 08:59:15 -0000 Message-ID: <65AECDF1F89AD411900400508BFC869F9C03BF@pdw-mail-1.dera.gov.uk> From: "Talbot Andrew" To: rsgb_lf_group@blacksheep.org Subject: LF: RE: Active antennas at LF.Wrong valve sp ecified 1 Date: Tue, 13 Mar 2001 08:59:25 -0000 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2650.21) Content-Type: text/plain; charset=iso-8859-1; format=flowed Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Sender: Sorry, I confused you all and remembered the wrong device. The valves are E55L Pentodes. (E88CC is a doube triode, sort of ECC88 then they ran out of numbers! ) The E55L presumably belongs to the EL55 family, 6.3V heaters, power pentode Octal base - Its all coming back to me now, the only time I ever used valves was back in teen years in the early 1970s Circuit is : Grid2 connected to anode and decoupled to ground. Input to each Grid1 from antenna connection via a 270 ohms stopper on each valve. Grid3 connected direct to cathode, 100 ohms from each valve to common output point, DC choke to gnd so the 100R acts as both cathode load and RF stopper / attenuator. Three of these blocks in parallel. 250V supply, positive grid bias applied to all 3 valves at comon input point adjustable 0 - 2V. This was described to me as a sort of cascode circuit but all internal to the one pentode structure - looks more like normal pentode operation to me. FETs are much easier to understand - wonder if a solid state version has been produced yet ? Andy > -----Original Message----- > From: Walter Blanchard [mailto:blanch@pncl.co.uk] > Sent: 2001-03-12 21:27 > To: rsgb_lf_group@blacksheep.org > Subject: LF: Active antennas at LF. > > > In the 1960's I had an active aerial using an 807 as the > front-end - with > 600v on it too! > Later modified to use an E186F instead. Why are they using > double triode > E88CC? > Can't possibly have the slope and overload characteristics of > an E186F. > > Walter G3JKV. > > > > -- The Information contained in this E-Mail and any subsequent correspondence is private and is intended solely for the intended recipient(s). For those other than the recipient any disclosure, copying, distribution, or any action taken or omitted to be taken in reliance on such information is prohibited and may be unlawful.