Last week, Robbie KB6CJZ and I provided a one-hour slide show with a show-and-tell session about the current advances in Digital-ATV to the JPL ARC in Pasadena, CA. Can you imagine, these hams are all part of the “flight communications systems” section of JPL for space probes and Mars-landers, etc….so they really know communications. So, I really had to “be on my toes” when talking about capabilities of RF communications used by DATV. For example: they completely understand that when the antenna gain gets impacted…you narrow the RF bandwidth (slow down the data rate) to compensate for the loss of antenna gain. So, when I talked about improved DATV S/N reception using RB-DATV…every head was nodding. Josh KB3UUS of JPL explained to us that some signals are as weak as around -160 dBm and JPL sometimes reduces the RF bandwidth down to 10 KHz to receive the incoming data stream from space. Josh went on to explain that the “closer" spacecraft at Mars and Jupiter are usually around -130 to -140 dBm.
The presentation covers DATV protocols, modulation technologies, current exciters, MiniTiouner analyzer, and useful URLs
They said they learned a lot about concepts of DVB-S and DVB-T and the overview of DATV exciters (including the Portsdown Project) and MiniTioune analyzer and appreciated the list of URLs to get started in DATV. Hopefully, we stirred up some interest in DATV at JPL ARC. The presentation PowerPoint and PDF files are available for download at
www.W6ZE.org/DATV/
Robbie and I received a two-hour private tour of the Mission Control Center room and the JPL Museum which has full size models of all their space vehicles. Very cool…and we did not have to elbow through any overwhelming crowds of competing visitors that occurs during JPL Open House events.
73…de Robbie KB6CJZ and Ken W6HHC