X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml Date: Thu, 24 Aug 2006 19:44:56 -0400 Message-ID: X-Original-Return-Path: Received: from mxsf25.cluster1.charter.net ([209.225.28.225] verified) by logan.com (CommuniGate Pro SMTP 5.1c.3) with ESMTP id 1347249 for lml@lancaironline.net; Thu, 24 Aug 2006 16:51:35 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.225.28.225; envelope-from=bobjude@charter.net Received: from mxip16a.cluster1.charter.net (mxip16a.cluster1.charter.net [209.225.28.146]) by mxsf25.cluster1.charter.net (8.12.11.20060308/8.12.11) with ESMTP id k7OKosKp015687 for ; Thu, 24 Aug 2006 16:50:55 -0400 Received: from 71-81-240-25.dhcp.stls.mo.charter.com (HELO gatewaypc) ([71.81.240.25]) by mxip16a.cluster1.charter.net with SMTP; 24 Aug 2006 16:50:54 -0400 X-IronPort-AV: i="4.08,165,1154923200"; d="scan'208,217"; a="767554700:sNHT33124636" X-Original-Message-ID: <005d01c6c7bf$271c87e0$6500a8c0@gatewaypc> From: "Bob Jude" X-Original-To: "Mail List Lancair" , "Dominic V Crain" References: Subject: Re: VHF feedback X-Original-Date: Thu, 24 Aug 2006 15:52:02 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_005A_01C6C795.3D863D20" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1437 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1441 This is a multi-part message in MIME format. ------=_NextPart_000_005A_01C6C795.3D863D20 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable I had that problem once. It is caused by RF pick-up on the audio = wires/cables/circuits and subsequent detection and amplification through = the receiver. I solved the problem in my plane by installing some (3) = ferrite toroids on each headset cable. The toroids serve to choke off = the RF currents in the audio wires. The head set cable has to be disconnected from the plug or some other = point in order to slip on the toroids. I suggest you try left side only = first. I purchased the toroids from DIGI-KEY on-line. Part number 240-2067-ND. Bob Jude N65BJ - still looking for a buyer. ----- Original Message -----=20 From: Dominic V Crain=20 Sent: Wednesday, August 23, 2006 2:01 PM Subject: VHF feedback Any advice on this one. Have a problem with loud squeal on VHF transmission - happens with = both VHF sets, but only from the left side. Right side doesn't happen. Have done all the suggested things from onlookers, cleaning terminals, = etc etc., and it only occurs after engine start. Use Lightspeed ANR 20G headsets. Changed the SPA 400 intercom with another identical unit - no avail. Can't quite recall when it started. Wondered if the installation of = Infinity grips in March might have introduced it with a wiring problem - = this was done by a avionics technician. Switching off the intercom and it goes away. It is quite loud. Any final suggestions? Dom Crain VH-CZJ ------=_NextPart_000_005A_01C6C795.3D863D20 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

I had that problem once. It is caused by RF = pick-up on=20 the audio wires/cables/circuits and subsequent detection and = amplification=20 through the receiver. I solved the problem in my plane by = installing some=20 (3) ferrite toroids on each headset cable. The toroids serve to = choke off=20 the RF currents in the audio wires.

The head set cable has to be disconnected from the = plug or=20 some other point in order to slip on the toroids. I suggest you = try left=20 side only first.

I purchased the toroids from DIGI-KEY on-line. = Part=20 number 240-2067-ND.

Bob Jude

N65BJ - still looking for a buyer.

----- Original Message -----
From:=20 Dominic V=20 Crain
Sent: Wednesday, August 23, = 2006 2:01=20 PM

Subject: VHF feedback

Any advice on this one.

Have a problem with loud squeal on VHF = transmission =96=20 happens with both VHF sets, but only from the left side. Right side = doesn=92t=20 happen.

Have done all the suggested things from = onlookers,=20 cleaning terminals, etc etc., and it only occurs after engine=20 start.

Use Lightspeed ANR 20G = headsets.

Changed the SPA 400 intercom with another = identical=20 unit =96 no avail.

Can=92t quite recall when it started. = Wondered if the=20 installation of Infinity grips in March might have introduced it with = a wiring=20 problem =96 this was done by a avionics technician.

Switching off the intercom and it goes=20 away.

It is quite loud.

Any final suggestions?

Dom Crain

VH-CZJ

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