M17 JVLA 35 is a radio source detected in projection against the M17 HII region .
In recent observations , its spectrum between 4.96 and 8.46 GHz was found to be positive and very steep , with \alpha \geq 2.9 \pm 0.6 ( S _ { \nu } \propto \nu ^ { \alpha } ) .
Here we present Very Large Array observations made in the 18.5 to 36.5 GHz region that indicate a spectral turnover at \sim 13 GHz and a negative spectral index ( \alpha \simeq - 2.0 ) at higher frequencies .
The spectrum is consistent with that of an extragalactic High Frequency Peaker ( HFP ) .
However , M17 JVLA 35 has an angular size of \sim 0 \hbox to 0.0 pt { . } { { } ^ { \prime \prime } } 5 at 8.46 GHz , while HFPs have extremely compact , milliarcsecond dimensions .
We discuss other possible models for the spectrum of the source and do not find them feasible .
Finally , we propose that M17 JVLA35 is indeed an HFP but that its angular size becomes broadened by plasma scattering as its radiation travels across M17 .
If our interpretation is correct , accurate measurements of the angular size of M17 JVLA35 across the centimeter range should reveal the expected \nu ^ { -2 } dependence .