The International Cessna^® 170 Association

Hi-Ho,
I have a two place intercom system, but would like to expand it to four on an as needed basis. Does anyone know if I can buy a portable system in plug it into the co-pilots plugs to expand it? I'm not interested in paying to rewire a system that works well 75% of the time.

Cheers
Lee

On my previous ride I "installed" a PA 400 4pl portable intercom. I say installed but all it required was routing some wires under the carpet etc. I mounted the unit via velcro immediately aft of the fuel selector plate. Once done it looked very sanitary and the internal lighting made it easy to see. The only thing odd was squelch adjustment. As long as I used the same brand of headsets things were fine but when they were mixed I had to adjust the squelch break between taxi and cruise cabin noise.

RB

I looked into this a couple months ago and I was unable to find a simple expansion that plugged into an existing mic/speak jack and worked off the existing power from your intercom.

I did find this, which IMHO was overkill, but it will do what you want. About $330 from most David Clark suppliers, I'm sure Sigtronics or someone makes a cheaper version. As far as I can tell it does plug into your existing jacks, but then all headsets must be plugged into the unit for interoperability. Maybe someone else out there has actually used one.





http://www.davidclark.com/PDFfiles/dccom200manual.pdf[/img]

I have a four place Sigtronics intercom in my plane. It works by plugging into the pilots mike and phone jacks. Probably would work off the copilot jacks too but I keep it on the pilots side because if the 9 volt battery fails you need to plug it in direct. Actally I plug the mike into a push to talk switch. It all works fine but I have considered having a permanant set up installed as I seem to go trough quite a few batterys and it is one more thing to turn on and off. Bill K

3958v wrote:I have a four place Sigtronics intercom in my plane. It works by plugging into the pilots mike and phone jacks. Probably would work off the copilot jacks too but I keep it on the pilots side because if the 9 volt battery fails you need to plug it in direct. Actally I plug the mike into a push to talk switch. It all works fine but I have considered having a permanant set up installed as I seem to go trough quite a few batterys and it is one more thing to turn on and off. Bill K

Aha, that is probably the one I was thinking of, I've seen a couple Sigtronics jobs around. The David Clark one in my post above works similarly, but at twice the cost no doubt

I've owned a SoftComm in a previous airplane. It worked good. Lot's cheaper than what's been mentioned so far.
http://www.softcommheadsets.com/aviatio ... rcoms.html

Thanks to all! Looks like a sigtronics or softcom is the way to go. This should help a good bit.

Cheers,
Lee

Lee,
Another way to hook up back seats is along the lines of the sportys double microphone/headphone adators, they work, I used them in flight school. The part numbers are 9419A and 1971A in that order. I wouldn't buy them but get parts and wire my own to fit my aircraft (the part numbers are so you get an idea of what they would look like). The down side is that you have wires running around the aircraft. The up side is when not in use they can be stowed.
brad

Does any one have a suggestion for where to place intercom jacks for the rear seat (or-better yet- a picture)? I have a PMA4000 to replace an intermittent 2 place intercom and three way switches for comms.

Thanks

A friend has the jacks installed inside the ashtrays in the rear seat. When you want to plug in you open the lid to the ashtray! It's a very neat solution.... If you are interested I could take some pictures, but it may take a week or so.

Mine were installed in the hatshelf immediately aft of the front "lip". Easily accessible, kept the excess cord behind the passenger on the shelf and almost completely invisible unless you went back there and looked straight down from above the shelf.

My back jacks are mounted on the side panels. Neat and out of the way, but can be a bit annoying to have that cord right at your hips.....

Here is where I mounted mine. I've not personally experienced 'em in flight but those who have don't seem to mind the location.


Steve

I slid my rear ashtrays out of their holders, cut the bottoms off with a hacksaw, and pop-rivited a flat piece of half-moon shaped aluminum within/across the top. The lid still closes upon it and it looks like ordinary ashtrays...until you open the lid to reveal the jack-sockets.
(I later found out those brand new (NOS), never ashed-in ashtrays were worth plenty to restoration-nuts and I should have sawn the bottoms out of old ashtrays instead.)

That's also a nice solution, Steve! (Clearly, the condition of your airplane and sidewalls and frames, etc., indicate the professional mechanic-owenership of your plane. I like the gray overall treatment.)
Is that an ELT mounted on the sidewall?

George,

Thanks for the kind comment on my circa 1992 interior decorating job.
Yes, that is where I decided to mount the ELT. I pondered mounting it aft of the baggage and relocating the strobe power supply also. But elected to put it there for easy access in the event...

Steve