M20J Antenna Identification

[marcusku]

 

 

 

I'm taking my commercial check ride soon and I'd like to make sure I know enough about the airplane.  Picture #1, I believe are Comm and Nav, which one is which?

Picture #2, there is one on each side of the front gear door, is that an antenna?

Picture #3, I'm not to sure what that is for, I know the two GPS looking antennas on top are for the GPS and Aspen.

Also, the two flat things on the upper part of the tail, is that for airflow?

Thanks!

 

 

[Guest]

Top antenna pair are Comm, blades or whiskers on the fin are nav/ glideslope, blades on the belly are transponder/ DME, #3 looks like Insight strike finder.

Clarence

[carusoam]

Get a good look at the nav antennas on the tail...

If you get a simple question about why they are there and how they can go wrong...

In the history of these antenna locations.... they are positioned the best to avoid the wing from blanketing their reception...

It would be hard to follow the ILS if blanketing would always occur...

All the antennas get similar consideration when their locations got selected...

Often, some MSers have a com antenna mounted on the belly... you may find one radio to work better while on the ground...

Some antennas may be hidden... under fiberglass wing tips or the faring in front of the tail... Some VORs and the ELT are hiding this way...

The fiberglass cowls and top of the instrument panel are know hiding places for some antennas as well...

PP thoughts only, not a CFII...

Best regards,

-a-

[N201MKTurbo]

The one on the belly could be an ADF if you still have one or if they didn’t remove the antenna.

[carusoam]

It might be good to post a pic of the instrument panel...

Some radios you are thinking about may not get mentioned by MSers not familiar with your plane...

A semi-modern King ADF is a square plate looking device, but will be noticeable by its King logo right on it...

For every box on the panel, there will be a matching antenna or two... a new radio, may have GPS, VOR, and ILS antennas...

Best regards,

-a-

[marcusku]

I don't have an ADF but do have a lightning strike detector.  Maybe that's the antenna on the belly?

[ArtVandelay]

I don't have an ADF but do have a lightning strike detector.  Maybe that's the antenna on the belly?

Yes, and if you don’t have antennas on your vertical stabilizer, then your VOR antennas are in the wingtips.


Tom

[Guest]

2 hours ago, ArtVandelay said:

Yes, and if you don’t have antennas on your vertical stabilizer, then your VOR antennas are in the wingtips.


Tom

He mentions 2 flat things at the top of the fin, blade style VOR antennas is my guess.

Clarence

[buddy]

Number 3 is your lighting strike detector antenna.

[OR75]

if you have two small blade antennas in the belly they may be for: transponder or DME or ADB-in 

you may get questions on engine accessories / ignition and electrical systems

 

[David Lloyd]

The transponder, DME or ADSB-in antennas could also be the little post and ball variety easily broken when trying to clean the underside of the plane with a long handled brush.

[mikefox]

Great questions!  The antennas in #1 are COMM 1 and COMM 2.  Antenna #2 is transponder or DME - they are both small blade antennas like that.  #3 is definitely strike finder.

If ever in doubt, the length of the antenna is inversely proportional to the frequency - that's why DME is smaller than COMM, for instance!

[marcusku]

Thanks for everyone's help!  Wouldn't you know the examiner didn't even ask me about the antennas, but it's good to know anyway.  I did survive my checkride, sure nice to have that one in the rear view mirror!

[mikefox]

Congrats!

[The Other Red Baron]

Congratulations! I’m hoping to finish mine soon. How were your maneuvers?

[gsxrpilot]

Congrats! I'm glad to have that one behind me as well.

[kortopates]

Congrats - that's a one fun!

[marcusku]

On 10/7/2020 at 2:31 PM, The Other Red Baron said:

Congratulations! I’m hoping to finish mine soon. How were your maneuvers?

Thanks!

Overall not bad, the two things that could have been better:

Steep turns, which normally go well, I lost airspeed during the maneuver and even chirped the stall warning.  I wasn't paying attention to airspeed, normally I set 2400 and 17-18" and it works out fine.  My examiner was heavier than what I'm used to and maybe I had a little more fuel on board than typical but I needed a higher power setting.  I told him this power setting is what has worked in the past and he told me that it couldn't.  I wanted to say that the problem was the extra weight in the airplane but didn't argue with him.   

Somehow I missed that you are supposed to have the wind perpendicular to eights on pile ons.  I compensated for the wind during the maneuver but didn't realize you are supposed to set it up that way.

My lazy 8's and could have been smoother but they did the job apparently.

[zerotact]

Did you find out if the Blade under the pilots seat was for the DME or the transponder?  Im assuming the blade under the co-pilot is the DME and then the one under the pilots seat is the Transponder, otherwise, the cables would cross over in the dash.