=== The 60 GHz Oxygen Resonances ===

Tretyakov, M. Yu, M. A. Koshelev, V. V. Dorovskikh, D. S. Makarov, and P. W. Rosenkranz. "60-GHz oxygen band: precise broadening and central frequencies of fine-structure lines, absolute absorption profile at atmospheric pressure, and revision of mixing coefficients." Journal of Molecular Spectroscopy 231, no. 1 (2005): 1-14.   http://radiometrics.com/data/uploads/2012/11/Tretyakova_JMS_05.pdf

more than 37 resonances:

||Quantum|| freq    || a1   || a2  ||a3       || a5    ||  a6   ||
||ID     || GHz     ||      ||     ||GHz/10⁵Pa||1/10⁵Pa||1/10⁵Pa||
||     1+||56.264774|| 543.4||0.014||1.703    || 0.3525||-0.0978||
||     3-||62.486253||1503.0||0.083||1.513    ||-0.4499|| 0.0844||
||     3+||58.446588||1442.1||0.083||1.491    || 0.6768||-0.1273||
||     5-||60.306056||2103.4||0.207||1.415    ||-0.6395|| 0.0699||
||     5+||59.590983||2090.7||0.207||1.408    || 0.6957||-0.0776||
||     7-||59.164204||2379.9||0.387||1.353    ||-0.6561|| 0.2309||
||     7+||60.434778||2438.0||0.386||1.339    || 0.6342||-0.2825||
||     9-||58.323877||2363.7||0.621||1.295    ||-0.1932|| 0.0436||
||     9+||61.150562||2479.5||0.621||1.292    || 0.1014||-0.0584||
||    11-||57.612486||2120.1||0.910||1.262    ||-0.5416|| 0.6056||
||    11+||61.800158||2275.9||0.910||1.263    || 0.5014||-0.6619||
||    13-||56.968211||1746.6||1.255||1.223    ||-0.3545|| 0.6451||
||    13+||62.411220||1915.4||1.255||1.217    || 0.3029||-0.6759||
||    15-||56.363399||1331.8||1.654||1.189    ||-0.2378|| 0.6547||
||    15+||62.997984||1490.2||1.654||1.174    || 0.1856||-0.6675||
||    17-||55.783815|| 945.3||2.109||1.134    ||-0.1172|| 0.6135||
||    17+||63.568526||1078.0||2.108||1.134    || 0.0658||-0.6139||
||    19-||55.221384|| 627.1||2.618||1.089    || 0.2560|| 0.2952||
||    19+||64.127775|| 728.7||2.617||1.088    ||-0.3036||-0.2895||
||    21-||54.671180|| 389.7||3.182||1.037    || 0.3558|| 0.2654||
||    21+||64.678910|| 461.3||3.181||1.038    ||-0.3968||-0.2590||
||    23-||54.130025|| 227.3||3.800||0.996    || 0.3170|| 0.3750||
||    23+||65.224078|| 274.0||3.800||0.996    ||-0.3528||-0.3680||
||    25-||53.595775|| 124.6||4.474||0.955    || 0.2227|| 0.5085||
||    25+||65.764779|| 153.0||4.473||0.955    ||-0.2548||-0.5002||
||    27-||53.066934|| 64.29||5.201||0.906    || 0.1349|| 0.6206||
||    27+||66.302096|| 80.40||5.200||0.906    ||-0.1660||-0.6091||
||    29-||52.542418|| 31.24||5.983||0.858    || 0.1388|| 0.6526||
||    29+||66.836834|| 39.80||5.982||0.858    ||-0.1680||-0.6393||
||    31-||52.021429|| 14.32||6.819||0.811    || 0.1667|| 0.6640||
||    31+||67.369601|| 18.56||6.818||0.811    ||-0.1956||-0.6475||
||    33-||51.503360|| 6.193||7.709||0.764    || 0.1947|| 0.6729||
||    33+||67.900868|| 8.172||7.708||0.764    ||-0.2216||-0.6545||
||    35-||50.987745|| 2.529||8.653||0.717    || 0.2246|| 0.680 ||
||    35+||68.431006|| 3.397||8.652||0.717    ||-0.2492||-0.660 ||
||    37-||50.474214|| 0.975||9.651||0.669    || 0.2566|| 0.685 ||
||    37+||68.960312|| 1.334||9.650||0.669    ||-0.2773||-0.665 ||
||Quantum|| freq    || a1   || a2  ||a3       || a5    ||  a6   ||
||ID     || GHz     ||      ||     ||GHz/10⁵Pa||1/10⁵Pa||1/10⁵Pa||

 * a1 is proportional to magnitude of the effect.  the center is around 59.4 GHz.
 * All of these lines are "pressure broadened" - they are sharper and more resonant in thinner air.  At full atmospheric pressure, they merge into one broad curve.

I was hoping there was a way to take advantage of these resonances - perhaps for beam focusing, or even tailoring a signal to punch through this resonance to reach the ground.  If this is possible, it is beyond what I can imagine.