My working theory was that the chittering (which is repeating and appeared to be location-specific) is in a non-binary Morse-like code, which is meant to be understandable by a skilled listener without requiring specialised equipment. I'm fairly certain that there's enough variation in there for a case-insensitive alphanumeric character set. However, even if I'm right, then the actual message is pretty short, probably 3-4 characters. With only that much to go on, and not many recordings, I don't think we have enough data to come up with a sheet.
But if what they said really is true and the message can be understood by listening, then I think I'm on the right track. And now I really wish I didn't accidentally ram the UA I used to have.
I have looked for morse code, too. But without a pause or other seperator between the morse-code-elements i see no plausble way to encode it properly. For example
A is .-
M is --
J is .---
Without a seperator how can you differentiate AM from J? Or 1 from EMM?
For example the new, 1.3 UA emits the following (audible) sequence: 1100110110. 1 is a upper tone, 0 is a lower tone, followed by a howl. Then it keeps silent and plays the same klicking sound again and again.
Nonetheless, the possibilities are not endless. And since morse code would be the only code audible and without audio editing, we can go through them, if you want. There are 388 possible solution for this ONE sequence alone. I've listed them for you here:
EADDT, EADNA, EADNET, EADTEA, EADTEET, EADTIT, EADTU, EADX, EANAEA, EANAEET, EANAIT, EANAU, EANEDT, EANENA, EANENET, EANETEA, EANETEET, EANETIT, EANETU, EANEX, EANLT, EANRA, EANRET, EATEAEA, EATEAEET, EATEAIT, EATEAU, EATEEDT, EATEENA, EATEENET, EATEETEA, EATEETEET, EATEETIT, EATEETU, EATEEX, EATELT, EATERA, EATERET, EATFA, EATFET, EATIDT, EATINA, EATINET, EATITEA, EATITEET, EATITIT, EATITU, EATIX, EATUEA, EATUEET, EATUIT, EATUU, EAXEA, EAXEET, EAXIT, EAXU, EA/A, EA/ET, EEGAEA, EEGAEET, EEGAIT, EEGAU, EEGEDT, EEGENA, EEGENET, EEGETEA, EEGETEET, EEGETIT, EEGETU, EEGEX, EEGLT, EEGRA, EEGRET, EEMEAEA, EEMEAEET, EEMEAIT, EEMEAU, EEMEEDT, EEMEENA, EEMEENET, EEMEETEA, EEMEETEET, EEMEETIT, EEMEETU, EEMEEX, EEMELT, EEMERA, EEMERET, EEMFA, EEMFET, EEMIDT, EEMINA, EEMINET, EEMITEA, EEMITEET, EEMITIT, EEMITU, EEMIX, EEMUEA, EEMUEET, EEMUIT, EEMUU, EETDDT, EETDNA, EETDNET, EETDTEA, EETDTEET, EETDTIT, EETDTU, EETDX, EETNAEA, EETNAEET, EETNAIT, EETNAU, EETNEDT, EETNENA, EETNENET, EETNETEA, EETNETEET, EETNETIT, EETNETU, EETNEX, EETNLT, EETNRA, EETNRET, EETTEAEA, EETTEAEET, EETTEAIT, EETTEAU, EETTEEDT, EETTEENA, EETTEENET, EETTEETEA, EETTEETEET, EETTEETIT, EETTEETU, EETTEEX, EETTELT, EETTERA, EETTERET, EETTFA, EETTFET, EETTIDT, EETTINA, EETTINET, EETTITEA, EETTITEET, EETTITIT, EETTITU, EETTIX, EETTUEA, EETTUEET, EETTUIT, EETTUU, EETXEA, EETXEET, EETXIT, EETXU, EET/A, EET/ET, EEZDT, EEZNA, EEZNET, EEZTEA, EEZTEE-, EEZTIT, EEZTU, EEZX, EPAEA, EPAEET, EPAIT, EPAU, EPEDT, EPENA, EPENET, EPETEA, EPETEET, EPETIT, EPETU, EPEX, EPLT, EPRA, EPRET, EWEAEA, EWEAEET, EWEAIT, EWEAU, EWEEDT, EWEENA, EWEENET, EWEETEA, EWEETEET, EWEETIT, EWEETU, EWEEX, EWELT, EWERA, EWERET, EWFA, EWFET, EWIDT, EWINA, EWINET, EWITEA, EWITEET, EWITIT, EWITU, EWIX, EWUEA, EWUEET, EWUIT, EWUU, IGAEA, IGAEET, IGAIT, IGAU, IGEDT, IGENA, IGENET, IGETEA, IGETEET, IGETIT, IGETU, IGEX, IGLT, IGRA, IGRET, IMEAEA, IMEAEET, IMEAIT, IMEAU, IMEEDT, IMEENA, IMEENET, IMEETEA, IMEETEET, IMEETIT, IMEETU, IMEEX, IMELT, IMERA, IMERET, IMFA, IMFET, IMIDT, IMINA, IMINET, IMITEA, IMITEET, IMITIT, IMITU, IMIX, IMUEA, IMUEET, IMUIT, IMUU, ITDDT, ITDNA, ITDNET, ITDTEA, ITDTEET, ITDTIT, ITDTU, ITDX, ITNAEA, ITNAEET, ITNAIT, ITNAU, ITNEDT, ITNENA, ITNENET, ITNETEA, ITNETEET, ITNETIT, ITNETU, ITNEX, ITNLT, ITNRA, ITNRET, ITTEAEA, ITTEAEET, ITTEAIT, ITTEAU, ITTEEDT, ITTEENA, ITTEENET, ITTEETEA, ITTEETEET, ITTEETIT, ITTEETU, ITTEEX, ITTELT, ITTERA, ITTERET, ITTFA, ITTFET, ITTIDT, ITTINA, ITTINET, ITTITEA, ITTITEET, ITTITIT, ITTITU, ITTIX, ITTUEA, ITTUEET, ITTUIT, ITTUU, ITXEA, ITXEET, ITXIT, ITXU, IT/A, IT/ET, IZDT, IZNA, IZNET, IZTEA, IZTEET, IZTIT, IZTU, IZX, UDDT, UDNA, UDNET, UDTEA, UDTEET, UDTIT, UDTU, UDX, UNAEA, UNAEET, UNAIT, UNAU, UNEDT, UNENA, UNENET, UNETEA, UNETEET, UNETIT, UNETU, UNEX, UNLT, UNRA, UNRET, UTEAEA, UTEAEET, UTEAIT, UTEAU, UTEEDT, UTEENA, UTEENET, UTEETEA, UTEETEET, UTEETIT, UTEETU, UTEEX, UTELT, UTERA, UTERET, UTFA, UTFET, UTIDT, UTINA, UTINET, UTITEA, UTITEE-, UTITIT, UTITU, UTIX, UTUEA, UTUEET, UTUIT, UTUU, UXEA, UXEET, UXIT, UXU, U/A, U/ET, ?DT, ?NA, ?NET, ?TEA, ?TEET, ?, ?TU, ?X
Some of them could be the names of star systems.