---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Thu 07/17/14: 4 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:15 AM - Re: P Lead Wires Adjacent to Headset Jack Wires (Robert L. Nuckolls, III) 2. 07:35 AM - Re: P Lead Wires Adjacent to Headset Jack Wires (Dan Jones) 3. 07:38 AM - Re: P Lead Wires Adjacent to Headset Jack Wires (stearman456) 4. 09:30 AM - Re: Re: P Lead Wires Adjacent to Headset Jack Wires (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 06:15:09 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: P Lead Wires Adjacent to Headset Jack Wires At 11:43 PM 7/16/2014, you wrote: > >In the interests of killing two birds with one stone, could I run my >headset and mic jack wires in the same 3/8" dia aluminum conduit as >my mags' P lead wires without screwing up my audio >signals? Inasmuch as the P lead wires need to be shielded I'm >thinking this is probably a really bad idea and would probably >cripple my audio but as it would make such a slick installation in >my case I thought I'd ask. Not a problem as long as you pay due homage to the physics gods . . . the shields for the p-leads should not come to ground at any location but the engine-end. Shields for the audio system terminate at the 'radio end'. But I'm curious, how is it that locations of the various and sundry components made this conduit an attractive option for holding this combination of wires? Bob . . . ________________________________ Message 2 _____________________________________ Time: 07:35:15 AM PST US From: Dan Jones Subject: Re: AeroElectric-List: P Lead Wires Adjacent to Headset Jack Wires Thanks Bob, I really appreciate the advice and help. I'm restoring a Stearman. The headset & mic jacks and intercom PTT for the front seat all reside on the front instrument panel. The radio and txdr are in a box in the rear cockpit mounted to the back of the front seat ahead of the stick. The mag switch is on the rear instrument panel on the extreme left and the airplane's main DC wiring harness runs down the right hand side of the fuselage from the rear cockpit to the firewall J box. I wanted to keep as much room as possible between the main harness and the audio harnesses so the front seat harness is going to run down the left hand side of the front cockpit and then downwards once abeam the rear instrument panel to the radio box. To protect the audio harness I want to run it in a small aluminum conduit and as that will parallel the P leads anyway I thought wouldn't it be slick if the P leads could be in there as well? A zinc chromate painted conduit of that size will be nicely camouflaged amongst all the link rods over there anyway and won't look as out of place as a bundle of small, 21st Century wiring would. And all the fat wires and fuses are up on the firewall inside the junction box and well away from the avionics in the back. The only CB's in the system are for the VHF, txdr, and the Alt field. The design goal for the airplane from the beginning was airline quality VHF radio - something that in an old open cockpit biplane is abit of a rarity! Thanks for the help! Dan Jones On 7/17/2014 7:13 AM, Robert L. Nuckolls, III wrote: > > > At 11:43 PM 7/16/2014, you wrote: >> >> >> In the interests of killing two birds with one stone, could I run my >> headset and mic jack wires in the same 3/8" dia aluminum conduit as >> my mags' P lead wires without screwing up my audio signals? Inasmuch >> as the P lead wires need to be shielded I'm thinking this is probably >> a really bad idea and would probably cripple my audio but as it would >> make such a slick installation in my case I thought I'd ask. > > Not a problem as long as you pay due > homage to the physics gods . . . the > shields for the p-leads should not > come to ground at any location but the > engine-end. Shields for the audio system > terminate at the 'radio end'. > > But I'm curious, how is it that locations > of the various and sundry components made > this conduit an attractive option for > holding this combination of wires? > > > Bob . . . > > ________________________________ Message 3 _____________________________________ Time: 07:38:21 AM PST US Subject: AeroElectric-List: Re: P Lead Wires Adjacent to Headset Jack Wires From: "stearman456" Thanks Bob, I really appreciate the advice and help. I'm restoring a Stearman. The headset & mic jacks and intercom PTT for the front seat all reside on the front instrument panel. The radio and txdr are in a box in the rear cockpit mounted to the back of the front seat ahead of the stick. The mag switch is on the rear instrument panel on the extreme left and the airplane's main DC wiring harness runs down the right hand side of the fuselage from the rear cockpit to the firewall J box. I wanted to keep as much room as possible between the main harness and the audio harnesses so the front seat harness is going to run down the left hand side of the front cockpit and then downwards once abeam the rear instrument panel to the radio box. To protect the audio harness I want to run it in a small aluminum conduit and as that will parallel the P leads anyway I thought wouldn't it be slick if the P leads could be in there as well? A zinc chromate painted conduit of that size will be nicely camouflaged amongst all the link rods over there anyway and won't look as out of place as a bundle of small, 21st Century wiring would. And all the fat wires and fuses are up on the firewall inside the junction box and well away from the avionics in the back. The only CB's in the system are for the VHF, txdr, and the Alt field. The design goal for the airplane from the beginning was airline quality VHF radio - something that in an old open cockpit biplane is abit of a rarity! Thanks for the help! Dan Jones Read this topic online here: http://forums.matronics.com/viewtopic.php?p=426837#426837 ________________________________ Message 4 _____________________________________ Time: 09:30:42 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: P Lead Wires Adjacent to Headset Jack Wires > >And all the fat wires and fuses are up on the firewall inside the >junction box and well away from the avionics in the back. The only >CB's in the system are for the VHF, txdr, and the Alt field. The >design goal for the airplane from the beginning was airline quality >VHF radio - something that in an old open cockpit biplane is abit of a rarity! Nothing in your narrative suggests any potential for 'gotchas' . . . but in any case, your risks are low . . . the worst case says you'll discover some effect we've not considered. Let us know the outcome! Bob . . . ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.