Well, the Nautel "HD ready" 10 k transmitter was quoted at around 58K when I saw it in Philly at the NAB radio show. Going from memory--I was really interested in the "analog" price without the fancy exciter.
Didn't pay attention to the Nautel exciter, but I have seen a BE exciter that produces both an analog and HD signal which is combined in that box to drive the transmitter. Hence, the subsequent power amplifiers have to operate Class A so as to not distort the digital signal. This exciter was going to market somewhere in the 25K range.
This would be if you do low-level combining, which also reduces the max rated TPO of a transmitter. The Nautel had a max TPO analog at 11 kw; in HD mode the max TPO was around 7 kw since it must run in a linear mode.
Another way to do this is to use a high-level combiner to feed a separate low-power HD transmitter and main transmitter into the same feedline and antenna. If you run 10 kw TPO, then the HD transmitter would need to be only a couple of hundred watts. The combiners I have seen quoted in the $15~20K range. Again, you need the HD exciter & linear power amp. to feed the combiner. So you would then be looking at somewhere in the $45 to $55 range for the project, not including any audio processing for the HD audio feed.
A final method, if you have the vertical real estate available, is to use a separate antenna for the HD transmission. ERI sells a fancy antenna which essentially combines a lot of plumbing, I am not sure what the FCC allows, but it would appear to be simpler just to use a low power antenna mounted below your analog antenna. Then the cost reduces down to the HD exciter & PA, and, given the low power used for the HD signal, 7/8th inch coax and a low-power FM antenna.
Given the enormous number of receivers out there, I could not justifyu any of these schemes just to be able to say the station was broadcasting in HD. Somebody noted on another list that the pioneers are the ones with arrows in their backs.
