In theory, your aircraft registration is also considered by the FCC to embody the authority to transmit on the aircraft band, so it should be in your initial contact somewhere. (Not just "orange Bonanza" or the like.)
This must not be an enforcement priority for the FCC, because it's common practice by pilots to omit the "N" from the number. The remaining portion of the N-number is not a legal callsign in the US, where all callsigns begin with K, W, A or N by international agreement.
Technically correct for some but not all. Airline call signs are also FCC issued and do not include the N number. FCC deconflicted FAA callsigns in their DB a little over a decade ago in cooperation with NTIA also. (Military aviation frequencies fall under NTIA jurisdiction not FCC.). Thus why you hear "Cactus" instead of "America West".
Another example would be the never ending CAP aviation callsigns that changed every few years until everyone got it settled, and the changing of many CAP FM callsigns to avoid overlap between NTIA/USAF callsigns and FCC Aviation callsigns.
Colorado Wing for example, held "Pikes Peak" as their NTIA/Military callsign, but Pike Peak was also a defunct airline with an active FCC callsign. Colorado Wing was switched to "Blue Mesa" to avoid transmitting the Airline's FCC callsign on the FCC-jurisdiction AM VHF Aircraft Band by a simple missed switch throw between the AM and FM radios.
Wyoming Wing was "King" which was also in use, and was switched to "High Plains".
This all happened forever ago, and is widely publicized or I wouldn't be mentioning it since NTIA/USAF get a little paranoid about their callsigns.
Prior to "Pilkes Peak", Colorado was issued three callsigns... "Pikes Peak" were aeronautical stations, "Red River" were mobile stations, and "Blue River" we're fixed location stations... Back when NTIA/USAF separated them. Wyoming was "King", " Queen", and "Jack" respectively.
Then there was a period of time where the aeronautical callsign was used with suffixes... "Air" for aircraft, "Mobile" for mobiles, no suffix for fixed ground stations.
(I've been Pikes Peak 120, Pikes Peak 120 Mobile, Blue Mesa 175, and Blue Mesa 45 over the years.)
The aircraft have had mixes of tail numbers and prefix numbers based upon Wing with both pro-word prefixes and at times the "Air" suffix for NTIA, and mixes of tail number, "CAPFLIGHT" and nowadays just "CAP". Controllers are STILL confused over "CAPFLIGHT" and "CAP" a decade later and you'll still hear both even though "CAPFLIGHT" hasn't been authorized in a coon's age. Partially that was tracked down to a bad internal FAA memo that had the change backward many years ago, it was eventually learned. Or so I heard in unofficially from a very high source once.
I've written about a billion training documents about which callsign to use for CAP trainees to use on which radios over the years. Entertaining to say the least. That's being kind, honestly.
Additionally, it should be noted that the International treaties for K, W, N, and A are superseded for Aviation worldwide, and "N" in aviation is the FAA's chosen standard related to aviation treaties, and is not directly related to the FCC treaties nor needed in NTIA/Military frequency use of Mil Band AM Air frequencies.
(But in that world I'm WY0X. Grin...)
Interesting side-note: Take a look at all of the radar and comm frequencies that would be required by an early AWACS aircraft and the typical filtering and selectivity/sensitivity available to RF engineers at the time of the first AWACS type aircraft, and you'll see exactly how we ended up slicing up the spectrum the way it ended up for both civilian and military use above VHF.
They had to engineer the comm systems not to interfere with the radar systems of the day and vice-versa, and also each other. Not easy in those early radios. Note they're never an even or odd multiple apart from each other on a spectrum chart.
Harmonics suck when transmitters and receivers and their antennas are all within the length of a 707.
They're also never 10.3 MHz or 11.? (Forgot) away in 2Freq+IF or -IF multiples either. Direct IF interference also seriously sucks at close distances with lightweight shielding and coax.
There's a metric ass-load of math and design layout of specrtum allocations triggered by the RF design and art of the day, that shows up in modern aviation band and military radar bands, and where they ended up. The history is pretty impressive considering the crappy performance of "state of the art" receivers and transmitters of the 50's up thru the 70's.
As a crazy-smart RF Engineer friend says, "Passive Intermod(ulation Interference) is the Devil's snack food!" Think there's a few loose metal on metal joints in the near-field of that giant flying saucer shaped antenna on top of an AWACS 707 or Hawkeye, acting as little RF diodes and mixing all that high power RF coming off that thing? Heh.
Incredible those aircraft even work at all, without jamming the crap out of themselves, if you think about it.
I guess I was bored enough to type all that up. Whee.
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