I haven't built an experimental yet, but I am planning on building a kit helicopter. In the meantime I wonder if I can get some assistance. I own a Mooney that lived in Nevada for a long time under a shade hangar till I moved back to Peoria. The avionics have been plagued with the micro fine dust that blows all around there and now I am having different issues related to poor connections. I've got most of them sorted out, but am puzzled by my marker beacon indicator. I can receive some beacons, but not all of them. For example I take off on runway 31 and receive the middle marker and outer marker for 13 as I depart, but when I return for landing on 31 I do not receive the marker beacon tones or lights. There are no NOTAMS indicating there is an issue with the 31 marker beacons so I'm sure it is something in my plane. Do all marker beacons broadcast on the same frequency and channel and if so why can I receive some and not others? I have King avionics witha KMA24. I appreciate your comments.