Panel Install

[robert7467]

My current situation is both of my avionics guys passed away and my plane has been down for around 5 years. I found a guy that will install the servos and sign off on my work. My problem is, I know these avionics guys are busy and I don't want to be a Chia Pet with constant questions. I did my last panel under guidance, but that was around 10 years ago, so I know how to pin and mount and I know just about every wire in that airplane. Here is what I had before:

KMA 24 

Sandel 3308

Garmin 420 28V

KX 165 28V

 

Here is what I have now: 

GMA 345

430W 14V

KX165 28V ( already have lone star converter installed)

2 GI 275's

Right now I am looking at the KX 165 and here is what I see so far ( I think this is Sandel stuff), I think GMA and 275 Manuals are pretty straight forward. 

P401/ J and P901 are daisy chained

P401 Pins M,N,11,12 are all tied together and capped off not going to a power source.

P901 11,12 has a resistor and are linked together. 

Are all of these Sandel stuff?

Also that line (noted on picture) with the shield circles, does that mean anything, or should I just do power and grounds and refer to the easier to read 275, 430W, GMA 345 Manuals?

Also, what color codes should I use for the headset and mic jacks? I know I have to ground at the connector, but I saw a video where a guy grounded the shield to the ground on the jack as well. 

This information will get me a long way before I get stuck again

 

Thank you guys! Like I said, its been about 10 years since I have done that, I know that Sandel was a more robust install. The Garmin manuals are more straight forward than this. 

[Mscheuer]

1 hour ago, robert7467 said:

My current situation is both of my avionics guys passed away and my plane has been down for around 5 years. I found a guy that will install the servos and sign off on my work. My problem is, I know these avionics guys are busy and I don't want to be a Chia Pet with constant questions. I did my last panel under guidance, but that was around 10 years ago, so I know how to pin and mount and I know just about every wire in that airplane. Here is what I had before:

KMA 24 

Sandel 3308

Garmin 420 28V

KX 165 28V

 

Here is what I have now: 

GMA 345

430W 14V

KX165 28V ( already have lone star converter installed)

2 GI 275's

Right now I am looking at the KX 165 and here is what I see so far ( I think this is Sandel stuff), I think GMA and 275 Manuals are pretty straight forward. 

P401/ J and P901 are daisy chained

P401 Pins M,N,11,12 are all tied together and capped off not going to a power source.

P901 11,12 has a resistor and are linked together. 

Are all of these Sandel stuff?

Also that line (noted on picture) with the shield circles, does that mean anything, or should I just do power and grounds and refer to the easier to read 275, 430W, GMA 345 Manuals?

Also, what color codes should I use for the headset and mic jacks? I know I have to ground at the connector, but I saw a video where a guy grounded the shield to the ground on the jack as well. 

This information will get me a long way before I get stuck again

 

Thank you guys! Like I said, its been about 10 years since I have done that, I know that Sandel was a more robust install. The Garmin manuals are more straight forward than this. 

Have you considered looking at the PMA8000G? It is less expensive, and IMHO, easier to use. Finally, the PMA8000G provides music distribution. Why might that be important? If the pilot wants to be the only one to hear audio alerts from the BT connected iPad, that is a selection. To the best of my knowledge, the GMA345 only allows the selection of what everyone will be hearing.

Thanks for letting me chime in.

Mark

[robert7467]

17 minutes ago, Mscheuer said:

Have you considered looking at the PMA8000G? It is less expensive, and IMHO, easier to use. Finally, the PMA8000G provides music distribution. Why might that be important? If the pilot wants to be the only one to hear audio alerts from the BT connected iPad, that is a selection. To the best of my knowledge, the GMA345 only allows the selection of what everyone will be hearing.

Thanks for letting me chime in.

Mark

All I care about is Mono, but the install calls for stereo, so I can hear direction of sound. I just want to wire her up and get her back in the air where she belongs. I am going to wire for stereo, but I honestly don't care..

[Skates97]

45 minutes ago, Mscheuer said:

Have you considered looking at the PMA8000G? It is less expensive, and IMHO, easier to use. Finally, the PMA8000G provides music distribution. Why might that be important? If the pilot wants to be the only one to hear audio alerts from the BT connected iPad, that is a selection. To the best of my knowledge, the GMA345 only allows the selection of what everyone will be hearing.

Thanks for letting me chime in.

Mark

I'll second the PMA products. I put the PMA 450B in my plane. If my son is flying he's listening to whatever he wants in the back seat and is isolated from the radio calls. My wife and I often listen to the same thing but if we want to we can listen to different things or she can listen to what she wants and I don't have anything playing if I'm on an IFR flight and don't want to miss a radio call. Another bonus to the stereo is that I can have my #1 radio on Tx/Rx and #2 on Rx to pick up the weather. If they are both receiving at the same time #1 is in my left ear and #2 in my right ear. It takes a little practice but you learn to ignore a call for someone else in your left ear and can listen to the entire weather recording instead of having it constantly cut in and out for transmissions where you have to listen to it 5 times to hear the whole thing.

[EricJ]

2 hours ago, robert7467 said:

Also that line (noted on picture) with the shield circles, does that mean anything, or should I just do power and grounds and refer to the easier to read 275, 430W, GMA 345 Manuals?

That line is indicating that all of those shields are grounded at Pin 15.

2 hours ago, robert7467 said:

Also, what color codes should I use for the headset and mic jacks? I know I have to ground at the connector, but I saw a video where a guy grounded the shield to the ground on the jack as well. 

Electrically just grounding one end of a shield (usually at the receiver if it is unidirectional) is better, but in aviation it is common to see shields grounded on both ends.   I think this is just for mechanical redundancy in case one end becomes disconnected, but who knows.

2 hours ago, robert7467 said:

This information will get me a long way before I get stuck again

 

Thank you guys! Like I said, its been about 10 years since I have done that, I know that Sandel was a more robust install. The Garmin manuals are more straight forward than this. 

 

[robert7467]

21 minutes ago, EricJ said:

That line is indicating that all of those shields are grounded at Pin 15.

Electrically just grounding one end of a shield (usually at the receiver if it is unidirectional) is better, but in aviation it is common to see shields grounded on both ends.   I think this is just for mechanical redundancy in case one end becomes disconnected, but who knows.

 

That's a lot of pins going to one ground pin. Should I combine them all using 18 Guage wire to pin 15. Thank you so much for your help!

[EricJ]

57 minutes ago, robert7467 said:

That's a lot of pins going to one ground pin. Should I combine them all using 18 Guage wire to pin 15. Thank you so much for your help!

Ground is ground, and there should only be very small, stray currents going through the shields, so the wire doesn't need to be large.   Any current in the shields should be going to the ground rather than through the pin into the connector, too.   The 18awg wire indicated from pin 15 to ground is mostly to carry the return current out of the nav/com, particularly during transmit.  The note referenced on the drawing may have some additional suggestions.

[robert7467]

It doesn't make any sense to ground the shields to pin 15, then ground to airplane. I have a dedicated ground bus bar. Should I just bundle those shields up and ground to the bus bar?

Also, the switched power outs and ins 12,N,11,M are all tied (jumped) together, capped off in my current harness..

P901 11,12 has a resistor and are linked together. (I am pretty sure this is a Sandel item and I can remove)

P401 pin J and 901 pin 5 are daisy chained together and I am not seeing any reference why in the sandel manual or KX manual. 

 

Once I get through these questions, I should be able to wire the Kx 165, I might have a couple questions on 275, but I think I got it

[robert7467]

Here is what I found on BeechTalk, So I am just going to leave those pins as is: Connect pins 11, 12, M, and N together. See the attached diagram. Internally the power goes through the on-off switch, out through pins 11 and M, then back into pins 12 and N.  

It still does make sense, but there was a reason I connected those pins together. Hope this helps.. 

[EricJ]

5 hours ago, robert7467 said:

It doesn't make any sense to ground the shields to pin 15, then ground to airplane. I have a dedicated ground bus bar. Should I just bundle those shields up and ground to the bus bar?

You want the shields grounded as close to their termination as possible, so the connector is the ideal place to do that, and pin 15 provides that.    You also want the shield grounds to be the same as the radio ground since their purpose is to reduce the amount of radiated rf or other electrical noise that gets into the shielded signals.   Using a ground further separated from the radio may reduce the effectiveness of the shields.

[MikeOH]

9 hours ago, robert7467 said:

It doesn't make any sense to ground the shields to pin 15, then ground to airplane. I have a dedicated ground bus bar. Should I just bundle those shields up and ground to the bus bar?

Also, the switched power outs and ins 12,N,11,M are all tied (jumped) together, capped off in my current harness..

P901 11,12 has a resistor and are linked together. (I am pretty sure this is a Sandel item and I can remove)

P401 pin J and 901 pin 5 are daisy chained together and I am not seeing any reference why in the sandel manual or KX manual. 

 

Once I get through these questions, I should be able to wire the Kx 165, I might have a couple questions on 275, but I think I got it

As another EE, I need to chime in and agree with @EricJ. It ABSOLUTELY makes sense where those grounds are located! If you don't understand shielding principles do NOT mess with the design!

[robert7467]

23 minutes ago, MikeOH said:

As another EE, I need to chime in and agree with @EricJ. It ABSOLUTELY makes sense where those grounds are located! If you don't understand shielding principles do NOT mess with the design!

So pin it to 15, connect all the 16 shields to it, then terminate it to the ships ground? They are also shielded at the Garmin connector. I guess I will wire as illustrated, as everything is being done according to the manual, but that doesn't make any sense to me whatsoever. There has to be other ways to do this! Maybe these guys should engineer for BMW! As written, it would probably take 12 gauge wire and a ton of solder to terminate those shields, the lead from the solder alone would prevent it from conducting due to resistance. I al looking at the diagram right now and its making sense to me, except for grounding the shields to pin 15, then grounding to the ship.

 

37 minutes ago, MikeOH said:

As another EE, I need to chime in and agree with @EricJ. It ABSOLUTELY makes sense where those grounds are located! If you don't understand shielding principles do NOT mess with the design!

 

[EricJ]

1 hour ago, robert7467 said:

So pin it to 15, connect all the 16 shields to it, then terminate it to the ships ground?

Pins 15 and 5 are the current returns for the radio unit.    They go wherever they need to go to serve that task.   There is an indicator to see Note 5, which may have some clarification on details.

There are some decent YT videos out there that show how to use solder sleeves as as easy way to terminate shields at a connector.   You can even buy solder sleeves with a wire already attached, and this makes it easier.   It's about the only place I recommend using solder sleeves on an airplane, or solder in general.   That makes connecting the shields to the recommended ground fairly easy, but the shields should terminate at the radio connector to provide maximum protection for the signals they're shielding.   With shielded connectors this is sometimes easier, but in any case, ground the shields as close to the connector as possible.   

1 hour ago, robert7467 said:

They are also shielded at the Garmin connector. I guess I will wire as illustrated, as everything is being done according to the manual, but that doesn't make any sense to me whatsoever. There has to be other ways to do this! Maybe these guys should engineer for BMW! As written, it would probably take 12 gauge wire and a ton of solder to terminate those shields, the lead from the solder alone would prevent it from conducting due to resistance. I al looking at the diagram right now and its making sense to me, except for grounding the shields to pin 15, then grounding to the ship.

I mentioned earlier that in aviation shields tend to get grounded on both ends, although this is not always optimal from a signal protection point of view.   Nevertheless, for mechanical redundancy or whatever reasons, many aviation shields get grounded on both ends.   It's not difficult to do, it's just a little more work.   Shields always need to be grounded as close to the connection of the signal they're protecting as possible to help prevent coupling any external energy into the signal being protected.   That's the purpose of the shield in the first place, so the diagram makes perfect sense from that perspective.

Edit:   How to terminate a shield with solder sleeve.
 

How to daisy chain shield for multiple wires:
 

 

[robert7467]

2 hours ago, EricJ said:

Pins 15 and 5 are the current returns for the radio unit.    They go wherever they need to go to serve that task.   There is an indicator to see Note 5, which may have some clarification on details.

There are some decent YT videos out there that show how to use solder sleeves as as easy way to terminate shields at a connector.   You can even buy solder sleeves with a wire already attached, and this makes it easier.   It's about the only place I recommend using solder sleeves on an airplane, or solder in general.   That makes connecting the shields to the recommended ground fairly easy, but the shields should terminate at the radio connector to provide maximum protection for the signals they're shielding.   With shielded connectors this is sometimes easier, but in any case, ground the shields as close to the connector as possible.   

I mentioned earlier that in aviation shields tend to get grounded on both ends, although this is not always optimal from a signal protection point of view.   Nevertheless, for mechanical redundancy or whatever reasons, many aviation shields get grounded on both ends.   It's not difficult to do, it's just a little more work.   Shields always need to be grounded as close to the connection of the signal they're protecting as possible to help prevent coupling any external energy into the signal being protected.   That's the purpose of the shield in the first place, so the diagram makes perfect sense from that perspective.

Edit:   How to terminate a shield with solder sleeve.
 

How to daisy chain shield for multiple wires:
 

 

I know how to make shields. I have done a panel install before. It doesn't make sense to pin to 15, which goes direct with separate wire to the ships ground. Ground them to the tray, that makes a little more sense, like how garmin terminates shields at the connector. Here is where I am at so far with the project. All those wires have heat shrinked wire splices for the shields. I just haven't put them on the connector yet or buttoned up the harness. I still have to pin the 165, 275s and GFC 500.

[EricJ]

42 minutes ago, robert7467 said:

It doesn't make sense to pin to 15, which goes direct with separate wire to the ships ground.

The idea is to get the signals to or from the circuit boards in the radio as cleanly as possible, and pin 15 is the closest connection to the grounds on the circuit board(s).   That's where the received signals enter the receiver, and where the outgoing signals are generated.   There are compromises that can be made, but generally that's the idea.

[robert7467]

8 minutes ago, EricJ said:

The idea is to get the signals to or from the circuit boards in the radio as cleanly as possible, and pin 15 is the closest connection to the grounds on the circuit board(s).   That's where the received signals enter the receiver, and where the outgoing signals are generated.   There are compromises that can be made, but generally that's the idea.

I see what your saying, but according to this, I am going to pin an 18 gauge wire to 15, then I am going to splice that wire, connect my (looks like 4)  shields and 18 guage wire to the ships ground. I think I like garmin manuals and install methods better. Like those 4 switched pins that have to be wired together, doesn't make any sense and it's not explained clearly in the manual. I am doing forensics and finally found an explanation of why those need to be pinned together. This is stuff that an old school avionics guy knows off of the top of his head and that wisdom needs to be passed along through tradition to us whipper snappers. Anyways, I know it looks stupid me asking questions and clarifying, but I just want it to pass the smoke test, so it's better to ask, than experiment. I was able to wire up that audio panel and 430 without any questions because the instructions are clear and the notations make sense too. Last time I installed this radio, I think we terminated the shields to the back plate of the tray. I wish my avionics guy was still alive. Off of memory, he could explain each pin, each configuration.