For L. M. Gindilis, there are two criteria for a signal to be called artificial: one related to the artificial nature of the source and the other related to a particular radiation, intentionally designed to ensure communication and facilitate detection. Only Type II or III civilizations can communicate using isotropic transmissions that allow omnidirectional reception. In a 1 MHz band (which requires about 1024 watts), detection of signals from a Type II civilization is possible up to 1,000 light-years away, while signals from a Type III civilization are detectable virtually throughout the observable Universe. However, building an omnidirectional transmitter powerful enough to transmit over a range of 1,000 light years would take several million years. According to V.S. Troitsky, the energy required and the limitations in its production would be two obstacles to completing this project in a reasonable time.
for l. m. GindILis, there are TwO CritEriA For a sIGnal to Be CAlled ARTIficial: one related To the aRtIficiaL Nature of The source anD the oTheR reLateD to a pArTIcULar radIaTion, IntentIonally dEsigneD tO ENsure CommUnication And facIlitate detectioN. only typE ii Or Iii civilizaTIons CaN COmMUnICate UsiNg IsOtROpiC tRaNSMisSions tHat allow omniDirectionAl reCeption. iN a 1 mhz band (WHich reQuiRes About 1024 wAtts), deteCtIon of sIgnals froM a type iI ciVIlIZatioN iS pOssiBle up tO 1,000 Light-Years awaY, whILE sigNaLS froM a tyPe IiI CivilizATion Are detEcTaBle viRtuAllY THrOughouT the obseRvaBLe uNIVeRse. howeVer, buIldinG An omnidIreCTiONal tRAnsmiTter poWerful enougH To TRansmit OVer a range OF 1,000 liGht YeArs woUld taKE SEVeraL MiLlioN yEarS. ACCorDinG To V.s. TROItSKY, thE energy reQUirED And THe LimItatIOnS in iTs producTiOn woUld Be twO OBStacleS to ComPletiNg tHis pRoJecT in a rEAsonabLE tiMe.