Encoder

This was an interesting thing not only to buy but wire in too.

There are many models of these and everyone we talked to used and recommended something different and Bendix King didn't offer one in their line, go figure again huh.

All in all they appear to be throw away units like lots of other things these days, you don't fix em you replace them so what it all boiled down to is we bought a popular one so we wouldn't have trouble replacing it later and have to rewire the ship to accomidated some other brand of unit.

This encoder also wires into the GPS unit as well as the Transponder and when you do this you must be careful that everything gets along because things can get messy on some combinations of equipment unless the GPS and the transponder has special diodes installed for this purpose otherwise I guess you would have to have two separate encoders.

Now you don't have to wire the encoder to the GPS but it gives the GPS unit another figure to do the math with for altitude in the event it doesn't get a good reading from the satellites.  Having no bases to go on I'm figuring more is better so I wanted ours wired in together to give us better odds.  I don't trust the GPS bearings that say accurate to 17 feet one day and 450 feet the next, is that latitude?, longitude? or altitude? or all of the above?, lol.  If it gives it an edge so be it, but it surely won't hurt to have an extra measure of insurance.

 
By the way if you are new to this here is another
added maintenance item and expense.

You must have these units calibrated together (every two years) meaning your altimeter and your encoder, transponder and in my case I guess my GPS, must all read the same and have the paper onboard the ship to prove it. Add a bit of extra cost here of about $175-$450 dollars for tweaking the units together.  The avionics guy I talked to said he had to remove the units from the ship to do it too and I sure don't like the idea of someone pawing around and removing my instruments. Also in the conversation I had with this fellow, he said part of calibrating it all required balancing them all in place. From what I got out of it that means that having different lengths and diameters of tubing on both the pitot tube and the static port affects the way the units read. I have no idea, at this time its all over my head lol. When we have this done I'll post the findings.

I'm thinking that means our ship is grounded if it has this equipment installed in it and it isn't up to required specs and if we didn't have this equipment installed it would pass as long as we stayed the required distance from an airport, more questions to get answered huh lol.   Later on I found out that if the units haven't been calibrated and or inspected the FAR says you must put an out of service sticker on the transponder until they are from what I get out of it or you could remove the transponder all together.

After we got the ship flying I was doing my 3 touch n goes at a class C airport (TYS) here in Knoxville, TN. The mode C wasn't giving out an altitude to the control tower, no big deal I guess because the controller guy I was talking to said it's very common and he just took my word for it on my altitude. Further investigation of the wiring of the unit revealed I never hooked up a triggering wire on the bus terminal. A simple move of a wire two posts down and were in business,,,we think lol.  Next time were in range of a Class C we will find out.

This is how it looks mounted in the ship.

It can be easily accessed with the nose panel removed so the tweeker person can turn the ajustments on it with out having to remove it from the ship,,We Think! lol.

END