Thanks for the 2007 FCC report, Jeff.
Channels: 7, 8, and 9 would fall around 178 to 183 Megahertz. That would have included the elements sized around 50 to 30% of the largest one on a unamplified roof top antenna.
I have worried about the Jack antenna since it does not have adequate room for the proper sized element to work with smaller amplified RV antenna. I suspect the actual range for picking up these channels may be only 50% of the range for the other's.
With two amplifiers I have no problems. I would expect a second amplifier would help with the Jack if a second amplifier works on it. I am talking about transmitted RF channel, not the traditional channel shown by the station for those confused.
I looks like Tom used to work for our local channel 9 (who moved RF channel from 29 back to 9). We count on Tom to keep things going there since they are our FOX network and carry the Vikings football games.
Mark :B