Eliminating mains hum from frequency modulated RF LC oscillators
You schematic is inaccurate in the real physical model so it won't work as expected in your schematic.

For example your decoupling 0.1uF cap is about 20nH in the 2 leads of 2cm and 1mm thickness (est) and 1cm track length. Meanwhile your resonator uses 33nH , so your supply has poor impedance and as others suggest perhaps 100pF in a small SMD cap is needed.  The overall layout is too big without a ground plane and therefore has a large loop antenna area for radiating and receiving stray electric fields.

I agree most of your hum is due to the large layout >5% of a wavelength for supply, ground and circuit loop path. This makes is prone to radiated noise and conducted ground noise.  Using an RF CM balun or RF CM choke is essential for your DC supply to decouple it from AC grounds in addition to an RF cap preferably a 100pF NPO cap for lowest ESR. 

Without a super narrow  IF band Spectrum Analyzer (&lt;100Hz) to examine AM vs FM , it is impossible to tell how much noise is in your SDR and how much is in the Tx.  But either way the hum is mostly in your LCO design and DC power/return paths.  If you had a lab RF gen. , then you can validate your SDR and a good RF SA to validate your noise source.  

When we made VCO's in the mid 90's for 928 MHz ISM band for we made custom ceramic hybrids with custom metal lids seam soldered over the hybrid soldered to a GETEK FR4 substrate with another ground plane > 60 dB CNR ( carrier to noise ratio and low phase noise for a 6kHz Tx bandwidth used for automated 2 way meter reading.


Dielectric constant, substrate loss tangent and shield capacitance all played a role in the design and I recall at the time 603 size 47pF NPO with 2 stage RC LPF were used to reduce supply noise to get down to 10 Ohms then used a design with low supply sensitivity with current sources unlike this one.  Now Murata makes low ESL caps of 100pF or more to cover this spectrum that are wider than long.


lessons to learn


How to calculate and measure inductance, ESL and ESR of tracks wires and passive components.
How to validate RF with a SA to isolate root causes of noise.
How to discover how critical layout with options for  ground planes , stripline , microstrip and cover shields to minimize interference using waveguide theory, controlled impedances, crosstalk and antenna sensitivity - How to measure  return loss measurement techniques and how to improve spectral purity with higher Q resonators and low Q supply decoupling with CM rejection.
This is just a start and the expertise is what makes good RF design Engineers worth more than others. ( I don't consider myself one, but I have learned from the best to know. )


Final words

If you master Ohms Law for RF using calculators for  impedance of tracks, wires and coupling capacitance between stripline, you can understand better how to use a Balun to raise CM impedance then attenuate with shunt loads while controlling the differential impedance.  This applies to 1GHz  PHY networks as well as your Oscillator designs so you can observe similar designs to see these features and apply impedance ratios and Q of resonator to control the resulting SNR.  It's all in the complex impedance ratios  like a 2 dimensional version of Ohm's law with reactive impedance, then it starts to look simpler with antenna aperture effects. (Directional loop antenna)