Help identifiying a loco part.

[mathewworley]

Hello Everyone,

     I got this Atlas GP38 from ebay and need help identifiying a part on it.  The part in question is just behind the cab on top of the locomotive. Its the peice (under the pen) on top of the inertial filter . To me it looks like a radio antenna of some sort but Im not sure.  Anyone have any ideas??

                                                                                                                                                                   Mathew

[dl109]

I believe the part your referring to is called a 'ground plane platform'.  It's purpose is to help in radio reception.  Usually you'll see radio antennas mounted on them. 

[mathewworley]

ok thanks, Ive also added a second picture (should have used this one first lol) that points out the piece . I thought thats what it was but I wasnt sure. Ill probably leave this up til the end of that day that way if anyone else wants to add anything.

[Backyard]

  Thanks for using us for a resource Matt, we're here if you need help.

Am I reading that you may drop the pic from your web-host? You don't have to do that, no one would not know what the post is about.

The round object on top of the ground-plane plate is a yellow beacon(molded in, it got painted), giving this locomotive two(an oversight by Atlas).

Ground-plane plates have been featured all over the tops of many locomotives...

The ideal spot is dead-center of the entire vehicle...the Southern Railway System experimented with this on SD40-2 Locotrol equipped units using fire-cracker antenna...the location of fans, etc prevent perfect placement.  The Southern ran electrical conduit(pipe) on top of the long hood to protect the antenna co-axial cable.

The idea of the "plate" is to fool the radio-signal into thinking that the plate surface was the entire object, without re-threading the co-ax cable, but in reality it did not pan-out, just worked better than the original placement of the antennae.

This "experiment" is not the same technology used by the Pennsylvania Railroad, with the top antenna that looks like handrails...that is an induction train radio.

[mathewworley]

I was goin to leave the pic with the post just at the end of the day, once I figured out what the part was, removing the post.(as not to take up room) Ive used sites before that, once your done with your post, ask that it be removed.

So the ground-plane plate was more of a experiment?? or standard equipment?? Was there certain areas that it was more suited for (mountains, valleys, etc) or just  used to enhance reception in general?

[Conrail Tweety]

So the ground-plane plate was more of a experiment?? or standard equipment?? Was there certain areas that it was more suited for (mountains, valleys, etc) or just  used to enhance reception in general?

Not as much for reception, but it improves transmission by shaping the radiated signal to lessen the amount wasted down toward the soil.

[Backyard]

  Hey Matt, here is a site that let's you forget it...

I imagine if you send money they'll through out the red carpet, however I've got two accounts & they never have said anything about cleaning it out.