X-Virus-Scanned: clean according to Sophos on Logan.com X-SpamCatcher-Score: 2 [X] Return-Path: Sender: To: lml@lancaironline.net Date: Fri, 06 Apr 2007 21:32:01 -0400 Message-ID: X-Original-Return-Path: Received: from mta16.adelphia.net ([68.168.78.211] verified) by logan.com (CommuniGate Pro SMTP 5.1.8) with ESMTP id 1970633 for lml@lancaironline.net; Fri, 06 Apr 2007 08:52:30 -0400 Received-SPF: pass receiver=logan.com; client-ip=68.168.78.211; envelope-from=glcasey@adelphia.net Received: from [75.82.254.207] by mta16.adelphia.net (InterMail vM.6.01.05.04 201-2131-123-105-20051025) with ESMTP id <20070406125140.LKP260.mta16.adelphia.net@[75.82.254.207]> for ; Fri, 6 Apr 2007 08:51:40 -0400 Mime-Version: 1.0 (Apple Message framework v752.2) In-Reply-To: References: Content-Type: multipart/alternative; boundary=Apple-Mail-5--11796486 X-Original-Message-Id: From: Gary Casey Subject: Re: Ground connection X-Original-Date: Fri, 6 Apr 2007 05:51:38 -0700 X-Original-To: "Lancair Mailing List" X-Mailer: Apple Mail (2.752.2) --Apple-Mail-5--11796486 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed I can't say that what I did was perfect, but I grounded all the instrument-panel related devices to a common ground bar that was bolted to the radio rack. Then there is one heavier ground wire that goes to the ground point on the firewall. It made it relatively simple to manage, reduced the weight of the wiring a little and it seems to work just fine. High current device grounds should definitely NOT be intermingled with avionics grounds. If you have a "number of different ground points" behind the panel that is probably okay as long as they are tied together with a low resistance connection (heavy wire or the chassis itself). However, aluminum assemblies are not the best ground systems as the oxide on the metal inhibits electrical connections and consequently there is a risk that some grounds might not be low enough in resistance. You might think that almost any ground will work for a radio that draws 1 amp, but while the ground might be good enough for that it might not conduct high frequencies well - that takes a very low resistance connection. Some will probably disagree, but I see no reason that they all have to physically come to a single point. On the other hand "daisy chaining" connections is likely a bad idea (the ground from one device connects to the ground pin of another device, which in turn is connected to a third device and finally the last in the chain is connected to a chassis ground). Gary Casey ES N224SG > I was wondering if listers could give me an opinion on electric and > avionics ground points. > > I have a number of different grounding points behind the > instrument panel. > In order to tidy up the spag, and perhaps improve the radio > performance, I wondered if I was to organise the ground points and > have the electrical services grounded to a common point and the > avionics to a separate common point. > Thanks > > > Dom Crain --Apple-Mail-5--11796486 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=ISO-8859-1 I can't say that what I did was = perfect, but I grounded all the instrument-panel related devices to a = common ground bar that was bolted to the radio rack.=A0 Then there is = one heavier ground wire that goes to the ground point on the firewall.=A0 = =A0It made it relatively simple to manage, reduced the weight of the = wiring a little and it seems to work just fine.=A0=A0High current device = grounds should definitely NOT be intermingled with avionics grounds. If = you have a "number of different ground points" behind the panel that is = probably okay as long as they are tied together with a low resistance = connection (heavy wire or the chassis itself). =A0However, aluminum = assemblies are not the best ground systems as the oxide on the metal = inhibits electrical connections and consequently there is a risk that = some grounds might not be low enough in resistance. =A0You might think = that almost any ground will work for a radio that draws 1 amp, but while = the ground might be good enough for that it might not conduct high = frequencies well - that takes a very low resistance connection.=A0 = Some=A0will probably disagree, but I see no reason that they all have to = physically come to a single point.=A0 On the other hand "daisy chaining" = connections is likely a bad idea (the ground from one device connects to = the ground pin of another device, which in turn is connected to a third = device and finally the last in the chain is connected to a chassis = ground).

Gary = Casey
ES N224SG

I was wondering if listers could give me an = opinion on electric and avionics ground = points.

=A0I have a number of different grounding points = behind the instrument panel.
=A0In order to = tidy up the spag, and perhaps improve the radio performance, I wondered = if I was to organise the ground points and have the electrical services = grounded to a common point and the avionics to a separate common = point.=A0

Thanks

=A0

Dom = Crain

= --Apple-Mail-5--11796486--