ACK ELT Wiring Conflict

[jimbo]

I have the ACK model E-04 121.5/406 ELT. I planned to run the telephone cable from the unit to the panel in the same cable run as my com antenna cable until I read at the top of pg 9 of the ELT install manual (http://www.ackavionics.com/pdf/E-04&...gle%20Page.pdf)

It says to avoid running this cable with strong EMI/RFI radiation, i.e. com cables.

Has anyone out there run these 2 cables together and has there been any interference? The telephone cable to the panel goes to the audio alert indicator then to the remote control switches.

Edit.....I emailed ACK the above question and this is their reply:
"I don't think it would cause any problems early ELT were susceptible to being set off by high levels of RF/EMI. The newer ELT are quite resistant to this problem however when possible it is good practice to separate them."

So I am going to route cables together in a flexible cable wrap and test it out. It there is interference then I will have to pull one of the cables out and reroute.

Jim
RV9A

[douglassmt]

I have my telephone cable run, for at least a couple feet, maybe more, with a nav coax, com coax, and transponder coax. No problems so far.

[RV6_flyer]

My 121.5 ACK ELT phone cable runs 6' with my Marker Beacon antenna coax. There have been no issues for the past 15-years.

[Canadian_JOY]

Just to add some clarification... Nav and Marker Beacon are RECEIVE ONLY so will not generate the higher levels of RFI required to be of concern for ELT's. Comm radios that transmit will be of concern.

There are a number of posts on the Glastar forum which indicate some builders did indeed run into troubles with comm radio transmissions triggering ELT's. This certainly is a high potential with 121.5 (TSO C91 and C91a) units, and particularly those that use unshielded "telephone" interconnection wiring.

When it comes to running wires, keeping them away from comm coax cables is a good idea, whether it's ELT wires, trim wires and even power wires for your tail position light. Separation isn't hard to achieve and brings great benefit in terms of keeping your aircraft free from EMI/RFI problems.