Advisory circulars are advisory, they have not gone through any rulemaking process, thus they do not have the oversight or accountability imposed as part of any rulemaking process.  As such, advisory circulars are non-enforceable.  Otherwise the local police could write rules about how to fold your socks, and you would immediately be subject to arrest if you didn't fold your socks according to their procedures.

That said, Advisory Circulars represent the accumulated knowledge of the time they were written, they are not exclusionary.  If you read the pre-amble to most ACs they specify they are not regulatory, and are only guidance documents.

AWOS
AUTOMATED WEATHER
OBSERVING SYSTEMS
AC 150/5220.16
 

FAA certified SuperAWOS
Under AC 150/5220.16

FAA Certification of SuperAWOS
Included
EQUIPMENT and MANUALS

Which specify how to do things
with FAA APPROVAL!

AIRPORT STANDARDS
AC 5300.13

305. RUNWAY SAFETY AREA (RSA). The runway safety area is centered on the runway centerline. Tables 3-1,3-2, and 3-3 present runway safety area dimensional standards. Figure 3-1 depicts the runway safety area.
a. Design Standards. The runway safety area shall be:
(1) cleared and graded and have no potentially hazardous ruts, humps, depressions, or other surface variations;
(2) drained by grading or storm sewers to prevent water accumulation;
(3) capable, under dry conditions, of supporting snow removal equipment, aircraft rescue and firefighting equipment, and the occasional passage of aircraft without causing structural damage to the aircraft; and
(4) free of objects, except for objects that need to be located in the runway safety area because of their function. Objects higher than 3 inches (7.6 cm) above grade should be constructed,

There are also areas near the runways to be kept clear of obstructions,
Proportional to the size of aircraft and the lowest visibility on an IFR approach

306. OBSTACLE FREE ZONE (OFZ). The OFZ clearing standard precludes taxiing and parked airplanes and object penetrations, except for frangible visual NAVAIDs that need to be located in the OFZ because of their function.

307. OBJECT FREE AREA. The runway object free area (OFA) is centered on the runway centerline. The runway OFA clearing standard requires clearing the OFA of above ground objects protruding above the runway safety area edge elevation. Except where precluded by other clearing standards, it is acceptable to place objects that need to be located in the OFA for air navigation or aircraft ground maneuvering purposes and to taxi and hold aircraft in the OFA. Objects non-essential for air navigation or aircraft ground maneuvering purposes are not to be placed in the OFA.

The logical conclusion is to apply AC 5300.13 criteria to the setback distance from the runway centerline (Obstruction Free Zone) for your SuperAWOS.  In brief, the minimum setbacks start at

A 'navaid' is a radio transmitter that provides electronic navigation, a two or three dimensional course that aircraft follow. 

There is no mention of AWOS anywhere in this regulation
AWOS systems do not provide navigation (course guidance)!

Part 171 reads as a listing of abandoned, and soon to be abandoned FAA navigational systems:  VOR, NDB, ILS, Simplified Directional Facility (SDF), DME, Marker Beacons, Interim Standard Microwave Landing System, and the venerable Microwave Landing System (MLS).

Within each section, applicable to its particular navigation transmitter, are some useful guidelines for good practices: Owner is responsible to provide qualified maintenance personnel, physical security to prevent tampering, maintenance and operations by authorized persons only, etc.

FCC REPAIR LICENSE

Getting a discrete VHF frequency for a legacy AWOS remains extremely cumbersome.    Years ago, AWOS systems were routinely connected to a nearby navigational aids, such as these, to output the AWOS weather message.  To adjust a navigational transmitter requires someone who knows what they were doing; an FCC Repair License is required to make adjustments to a transmitter.  A licensed FCC technician should know how to read their test equipment, which they will need to assure a transmitter is behaving within specification.

The SuperAWOS transceiver has no field adjustments, it is a sealed unit; only the manufacturer (us) can make any adjustments.  The only action possible on the transmitter in the field is to remove and replace; after which the system performs all the diagnostics a technician could perform, which are reported to us remotely. 

There is no regulation requiring an FCC repair license to remove and replace a sealed, non-adjustable transceiver module!

PERIODIC VERIFICATION OF TRANSMITTER

Legacy AWOS systems transmit in the blind on a discrete frequency.  Should their transmitter fail for any reason, no one will know (unless a pilot happens to notice and is inclined to tell the FAA). 

There are four measures necessary to verify a radio transmitter is functioning

Legacy AWOS systems lack means to monitor these performance parameters, so they require someone knowledgeable, with test equipment, to periodically go to the site and check the transmitter.  These tests require sophisticated radio test equipment, and an FCC licensed technician to know what they are doing.

Realizing the validity of this need, we built into the SuperAWOS internal diagnostics that measure ALL of these parameters every day, which are also reported to us daily.  If there is any out of tolerance condition we know it within 24 hours, and an exchange plug & play module is on the way; no license required.  When the module is swapped in the field, which requires no tools, the system runs a complete transceiver test that confirms for us, and for FAA, that all parameters are within tolerance.

In 1996 the FCC created FCC 87.219 specifically to allow this system, (which FCC called Automated Unicom, because that is the radio spectrum it shares) to share existing Airport VHF Common-Traffic Advisory Frequencies (CTAF); unicom and multicomm.

• As an FCC approved transmitter, each SuperAWOS has an FCC DEVICE LICENSE (A little label physically attached to each internal transmitter)
• The Airport is granted AUTHORITY over its  assigned unicom frequency by virtue of the Airport's FCC UNICOM STATION LICENSE
• SuperAWOS is an FCC APPROVED DEVICE (transmitter) operating under the AIRPORT'S AUTHORITY

If you have questions about your Airport unicom station license, here are links to help you navigate FCC.GOV

FCC Unicom Station Renewal Paper Form*Each transmitter has a DEVICE license, which is a certification that the transmitter operates in accordance to FCC requirements.  Each SuperAWOS, with its embedded transceiver, operates under the AUTHORITY of the Airport to use its own assigned CTAF.  Anyone using the CTAF does so with the permission of the Airport (or not).  if someone interferes with the Airport's use of its licensed frequency, then the Airport can file an 'interference' complaint, which allows the FCC to protect the Airport's use of its frequency (for example from crazy neighbors with a hand-held radio).

Interestingly, by prior coordination, Ken Kraus, then head of the FAA AWOS program, inserted into the FCC's Automated Unicom ruling '96-1' in 1996 the standard for automated unicom sensor locations:

(5)  If weather information is provided by an automated unicom:

     (i) weather sensors must be placed in order to adequately represent the weather conditions at the airport(s) to be served;

That's pretty obvious!