---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sun 06/07/09: 2 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 10:21 AM - RF interference fix? (Erich_Weaver@URSCorp.com) 2. 07:14 PM - Re: Cessna 150F Landing/Taxi light switch. (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 10:21:00 AM PST US Subject: AeroElectric-List: RF interference fix? From: Erich_Weaver@URSCorp.com >From first flight, the GRT EFIS and EIS on my RV have indicated momenta ry, anomalously high fuel pressure readings, typically just before take-off and also when entering and in the pattern. Stewed over that for over a yea r before asking myself the question - how does the system KNOW Im going t o takeoff or land? Asking that question led me to the only possible answ er: it knows because I get on comm and announce it! A couple of weeks ago I confirmed this - every comm transmission resulted in a sharp rise in fu el pressure. Yesterday I took it a step further, seeking to determine wha t the propogation mode was, and reasoned it was either RF interference or some sort of magnetic coupling associated with the increased power requirements during comm transmissions. The easy test was to get out m y battery operated handheld transceiver and transmit from inside the cock pit with the engine running and the EFIS/EIS powered up, so I did that firs t. Bingo - a similar increase in the fuel pressure reading, although to a lesser degree than with ship's comm. Also noticed a lot of noise on my handheld when receiving from inside the cockpit - noise that isnt noticeable on ship's comm, nor on the handheld normally.So, now Im feel ing pretty high and mighty with my diagnostic skills, but the problem still remains - where do I go from here to fix this? thanks erich This e-mail and any attachments contain URS Corporation confidential information that may be proprietary or privileged. If you receive this message in error or are not the intended recipient, you should not reta in, distribute, disclose or use any of this information and you should dest roy the e-mail and any attachments or copies. ________________________________ Message 2 _____________________________________ Time: 07:14:57 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Cessna 150F Landing/Taxi light switch. At 06:24 PM 6/6/2009, you wrote: >I have a very basic question. The switch in question burnt out so I >obtained a replacement. For the life of me I can't figure out which >wire goes where. I have three wires, power and feeds to the Landing >and Taxi lights. The switch has four connectors marked H,R,A, >B. The case is marked 600 and is a pull switch with two positions. >Can anyone help? I am aware it is not RV related. When I'm not >flying my RV4 I have the Cessna to take pictures etc. >SSD It has been a VERY long time since I've seen these switches installed on the Cessnas but if it's a 4-terminal switch I suspect that an ohmmeter test will show that with the switch has no connections with the handle all the way in. With the handle pulled to the first notch, I think the pair of terminals furthest from the panel will be connected to each other. This pair is the taxi light circuit. With the handle all the way out, the pair of terminals closest to the panel will be connected to turn on the landing light. In this position, the taxi light will be out. Here's an exemplar 4-terminal push-pull switch from Cole-Hersee Emacs! Bob . . . --------------------------------------- ( . . . a long habit of not thinking ) ( a thing wrong, gives it a superficial ) ( appearance of being right . . . ) ( ) ( -Thomas Paine 1776- ) --------------------------------------- ------------------------------------------------------------------------------------- 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.