TXPD or DME Antenna on Wing Inspection Panel
 

Is there any reason not to mount the DME or ADSB and Transponder Antennas on the wings inspection panels? (provided one goes on L wing the other on R wing to maintain separation)

I asked this question to one of the "senior" members of this forum whom I trust with regards to the advice he gives. He was concerned with the wear and tear on the antenna/coax junction if the antenna was mounted on the inspection plate. He recommended putting it right next to the opening. Not on the cover plate.

Not sure what the cable length would be out to a panel but it's probably more than fuse mounted antennas, these cables need to kept as short as possible.

Thanks Walt, where do I find out the max cable length? I found the same note in the install manuals, but a max length was not stated.

And would a bulkhead fitting reduce the signal even further? https://www.steinair.com/product/bnc...-femalefemale/

My issue is a lot of antennas on the belly which would be too close together if mounted on the belly.
1 ADSB IN
1 FLARM
1 DME
1 TXPD
1 COM
1 MARKER BEACON

High Freq transmitters like Xpd, DME should be kept as short as possible, usually 6' or less desired for RG400.
Other receive only antennas are not as important.
Com antenna (transmitter) should not be any longer than nec.
Yes every connector has a loss so less is better.

Garmin Length Chart
 

This is from the installation manual for the Garmin GTX-327 Transponder. I believe the ECS 311601 is the one I went with since my cable run was definitely over 6 ft. Bought the connectors from them as well since RG connectors are too small for the cable diameter.

I see that you are in Slovakia, so your regulations maybe different but do you really need a Marker Beacon and DME?

For Marker Beacon, the internal wing tip mounted antenna works well. I had a MB in my original panel and used a copper strip in the wingtip for the antenna.

Question: What is FLARM?

Or in the cowling...1m of coax with the shield stripped off, glassed in, and a bulkhead BNC connection in the firewall. Works great.

Thank you all for all the valuable inputs!

Dan, that table is very helpful.

Rick, you are right, the local authority would not approve the plane for IFR ops as long as it doesn't feature certified antennas. DME & Marker is compulsory here, as well as dual ILS.. That's Europe..(can't do anything about it)

Flarm is an anticollision (warning) device. I plan to install Powerflam which can display Flarm (mostly used by gliders and GA in Europe), ADS B and Transponder traffic. The output protocol can be converted to TIS & displayed on TIS compactible devices. More info here: https://flarm.com/products/powerflarm/