On his website, David has posted a page showing his results with an “Itty Bitty Radio Telescope” connected to an RTL-SDR dongle. The Itty Bitty Radio Telescope is a small radio telescope that can be used for simple and educational radio astronomy experiments. The telescope consists of an 18 inch directv satellite dish with low noise block (LNB), a satellite finder and an RTL-SDR dongle connected to a laptop.
The LNB converts input frequencies of 12.2 GHz to 12.7 GHz down to 950 MHz to 1.45 GHz which is a range that the RTL-SDR can receive. In his YouTube video posted below David points his Itty Bitty Radio Telescope at the sun and shows the associated increase in the noise floor on SDR# due to solar radio emissions. More information and possible experiments with the Itty Bitty Radio Telescope can be found in this PDF.