Len14043 said:
Even if the signal varies by decades, a 10-fold increase in power will nearly double the distance the signal is reliably received. If we follow your logic, then IBOC at 0.1% injection instead of the current 1% wont make much of a difference. Besides, FM IBOC in cars works fairly well now. Reception in buildings is the problem.
With respect to the "whole host of problems", it depends on who you talk to. For dxers, I'm sure it will cause problems.
Actually, it will do nothing in the fringes when the signal strength varies by several decades as you drive in the car, for the reason I stated earlier. And the same problem applies to the approach path of any major airport. Widely fluctuating signal strengths doom HD lock. Cars and airport approach paths are HD problem areas, unless you want a 60 dB power increase, HD won't stay locked under those conditions.
I measured 6 to 8 feet more penetration into a building. About enough for a row of cubicles. Office listening is streaming or iPod. Deal with it. 10 dB won't change that.
I did measure reliable HD lock at present power levels 70 miles from Dallas Ft. Worth. The cows in the field, I am sure, appreciate HD radio. 70 miles reliable lock with a stationary receiver away from airports. Exactly - how far is far enough for you? How many more cows do you need to cover outside the metro areas?
Let's take another look at the 10 dB increase. Right now, you have a maximum of 1000W on the sidebands. That isn't enough to reflect in the upper atmosphere. There are very few reports of tropos on 1000W stations. The situation changes dramatically with 10,000W stations, which is the equivalent of the IBOC sidebands you are proposing on full class C. We are presently at historically low sunspot activity. That won't last forever, it is cyclic. Once the sunspots return and you get tropos daily during the summer, these increased sidebands are going to propagate hundreds of miles, wiping out reception of local stations all over the country - unpredictably. It is inevitable. It would be far better to keep the power levels low enough to keep them out of the upper atmosphere, or risk massive disruptions in the future, on the order of magnitude of what is happening now to AM. AM is a throwaway band right now, brokered ethnic, talk, and sports. FM is the money band - do you really want consumers tuning in to local stations - and due to the capture ratio effect - hearing very loud interference instead? They will have even more motivation to tune out of radio entirely!
That is just one massive complication - there are a lot of others like overlapping IBOC sidebands in densely packed population centers like the NE. Primarily affecting the non-comm band. Do you really want religious broadcasters throwing their sidebands all over the place wiping out NPR stations? You are giving them the tools to legally jam adjacent stations, and jam they will - to keep the "evil liberals" off the air.
Need I go on? IBOC has trashed the AM band, with sidebands audible 1000 miles in the daytime and who knows how far at night, obliterating local stations - like 610 in Houston due to KMKI sidebands almost 300 miles away at night. So with AM a disaster because of overpowered sidebands, let's re-make FM in its image - THAT is YOUR logic!
