Intercom Principles

[Gavin Bell]

Work in progress at the minute is the re-wiring of radio and intercom (Narco 810 and PM501 respectively). On inspection I found so many poor practices that I have remove dit all and am currently building new looms on the bench to go in. The main issue with my installation was RF noises to the point that the squelch had to be turned up so high to get intercom that the radio was unreadable.

Some of the poor practices found:
braiding of screened wires used as earth returns
earths taken to aircraft frame ground at different locations - creating earth loops

I took a look at the PS Engineering website and found some really great information, including the following powerpoint that steps through the principles of wiring an intercom (and radio)



http://www.ps-engineering.com/support.shtml

Anyone with intercom / rf noise issues could do worse than to download and read through this powerpoint

Gavin

P.S. The support from PS-Engineering is 2nd to none - it only remains to see if I can make a good job of the wiring......................