Marker Beacons

We’ve tried everything to get the marker beacons to work on a relatively new Garmin intercom, including trying a loaner unit, checking wiring, and a new antenna to no avail. Every time the technician tries something new, we have to fly it over the marker beacon transmitter and that is getting old. This isn’t on a Cirrus, rather it’s on an Archer, but you folks all have the Garmin intercom and might have had a similar problem. Garmin will honor the warranty, but we are not sure whether it is the unit or not.

Sounds like you have replaced everything except the rack (assuming you’ve swapped out the antenna cable). I believe the antenna connection goes through the rack, so you might try swapping it out for a known good unit.

A well-equipped avionics shop should have a marker beacon tester, like this one. That will save you a lot of flying over beacons.

Good luck!



Stupid questions…are you getting the “O” or “M” lights and just not the sound. Have you tried both High and Low sensitivity?

Do you know that the beacon you are using is operational?

I’m sure you have tried all this, however, I ran into the case where the beacon was INOP after my installation test flight and I assumed that it was the receiver. D’oh!

Speaking of MB, I flew over an airway MB about 4 weeks ago (yeah there’s stll a few of them around). Surprised the hell out of me.

Use a signal generator to de-bug–much easier!

The marker beacon lights don’t work either. Yes, we also checked the high and low sensitivity. Yes, we’ve flown over marker beacons at two different airports, so we’re convinced it’s not the transmitters. Our next step is probably to find a guy with a marker beacon tester. It’s a good thing we really don’t need marker beacons. Mike had a good idea to check the rack. They tested the cable somehow.

In reply to:

It’s a good thing we really don’t need marker beacons.

Well, not exactly. See FAR 91.175(k).

(k) ILS components. The basic ground components of an ILS are the localizer, glide slope, outer marker, middle marker, and, when installed for use with Category II or Category III instrument approach procedures, an inner marker. A compass locator or precision radar may be substituted for the outer or middle marker. DME, VOR, or nondirectional beacon fixes authorized in the standard instrument approach procedure or surveillance radar may be substituted for the outer marker. Applicability of, and substitution for, the inner marker for Category II or III approaches is determined by the appropriate part 97 approach procedure, letter of authorization, or operations specification pertinent to the operations.

We’re not too worried about not having marker beacons since we are equipped with a Garmin 430 and DME.