M20J Belly King Air Antenna

[JayMatt]

On the belly of my airplane, I have an antenna that has a nasty chip in it and the metal that's inside it is rusting. I have no Idea what antenna it is other than it looks like these. I will take a picture tonight when I get back out to the hangar. As I put the plane back together I figure I may as well fix every little piece I come across. 

https://www.aircraftspruce.com/catalog/pnpages/11-02852.php?gclid=CjwKCAjw_YShBhAiEiwAMomsEE18nasJ5XnqbNuOeE1XJSqizTng5ZPI6miZhLFD2P7t34q5Kx1MuRoConAQAvD_BwE

 

https://www.aircraftspruce.com/catalog/avpages/antenna11-13830.php

 

The prices are dramatically different ...

Any opinions or thoughts on the matter I should look at? 

[EricJ]

It is most likely your transponder.   If you have a DME it might be that, too, or if you have ADS-B-in you may have a repurposed DME antenna connected to that.    They all look the same.

If you only have one, and none of the little stubby stick antennas, either, then it is most likely your transponder.   If so, just find a replacement transponder antenna.   They're all essentially the same spec.

 

[KSMooniac]

I concur that it is likely your transponder antenna.  If you're buying a replacement, you'll have to choose a TSO solution, unfortunately.  You can likely find a good used one for very modest money.

[1980Mooney]

32 minutes ago, JayMatt said:

On the belly of my airplane, I have an antenna that has a nasty chip in it and the metal that's inside it is rusting. I have no Idea what antenna it is other than it looks like these. I will take a picture tonight when I get back out to the hangar. As I put the plane back together I figure I may as well fix every little piece I come across. 

https://www.aircraftspruce.com/catalog/pnpages/11-02852.php?gclid=CjwKCAjw_YShBhAiEiwAMomsEE18nasJ5XnqbNuOeE1XJSqizTng5ZPI6miZhLFD2P7t34q5Kx1MuRoConAQAvD_BwE

 

https://www.aircraftspruce.com/catalog/avpages/antenna11-13830.php

 

The prices are dramatically different ...

Any opinions or thoughts on the matter I should look at? 

The second one is dramatically less because it says it is non-TSO’d and for Experimental aircraft. 

[GeeBee]

You need a TSO'd one and this one works for a lot less money. I have it on my Ovation with a Garmin 345

https://www.aircraftspruce.com/catalog/avpages/comant105.php

[JayMatt]

54 minutes ago, GeeBee said:

You need a TSO'd one and this one works for a lot less money. I have it on my Ovation with a Garmin 345

https://www.aircraftspruce.com/catalog/avpages/comant105.php

Is that a one type fits all antenna? Or am I supposed to track down exactly which one it is and make sure its the right type? I do have an old 3 something with the green and black screen and a 430.  

Guess I just saw all the other responses. I have a status installed now so I wonder if I even need the antenna anymore. I'll have to get it checked out I guess

Edited March 27, 2023 by JayMatt
didn't read

[trevttu76]

Those shark fin antennas on the belly are typically one of the following; either a DME, or transponder antennas.   Do you have more than one?  If not, then assume it is transponder.  

[GeeBee]

2 hours ago, JayMatt said:

Is that a one type fits all antenna? Or am I supposed to track down exactly which one it is and make sure its the right type? I do have an old 3 something with the green and black screen and a 430.  

Guess I just saw all the other responses. I have a status installed now so I wonder if I even need the antenna anymore. I'll have to get it checked out I guess

Fits either DME or Txp. 900-1100 mhz range.

[Shadrach]

It's likely that your current antenna is a King KA 60 but there's only one way to find out for sure. Concur with others that it's likely serving as a transponder/ADS-b antenna. The KA 61 you found on spruce is Kings updated direct replacement for the KA 60. It's less than $1000 bucks so cheap in aviation terms but why spend the money for no discernable performance gain when you can have a NOS KA 60 in original packaging for under $200. First step is verifying what you have so you can ensure the replacement is plug and play.

New KA60 DME Transponder Antenna PN 071-1174-00 With KN 63 Connector Kit | eBay

[Will.iam]

1 hour ago, Shadrach said:

It's likely that your current antenna is a King KA 60 but there's only one way to find out for sure. Concur with others that it's likely serving as a transponder/ADS-b antenna. The KA 61 you found on spruce is Kings updated direct replacement for the KA 60. It's less than $1000 bucks so cheap in aviation terms but why spend the money for no discernable performance gain when you can have a NOS KA 60 in original packaging for under $200. First step is verifying what you have so you can ensure the replacement is plug and play.

New KA60 DME Transponder Antenna PN 071-1174-00 With KN 63 Connector Kit | eBay

So if you have the needle ball type can you replace it with one of these? I saw where the drag coefficient for a needle ball is about the worse thing you can have but it’s cheap. 

[KSMooniac]

8 minutes ago, Will.iam said:

So if you have the needle ball type can you replace it with one of these? I saw where the drag coefficient for a needle ball is about the worse thing you can have but it’s cheap. 

Correct.  The streamlined fin antennas are also harder to break off the belly when you're cleaning it. 

[Shadrach]

16 minutes ago, Will.iam said:

So if you have the needle ball type can you replace it with one of these? I saw where the drag coefficient for a needle ball is about the worse thing you can have but it’s cheap. 

I have no experience with the needle ball type antennas. As long as the coax is correct (RG-142 or RG-400) it should work fine.