Driving to the store starts with 1680 AM (Part 15) clearly on the dashboard, until a block later it fades to background.
Driving to the store starts with 1680 AM (Part 15) clearly on the dashboard, until a block later it fades to background.
Along the way different hums and buzzes come and go at 1680, some probably from power transformers, but others sound hash-like, the way a raw digital signal would sound. After all, the phone company uses AM radio frequencies and higher for their DSL service, so it is reasonable to imagine that some of this gets radiated into the air. Of course the chunk at 1680 would only be a small bit of DSL’s total bandwidth, but interesting to contemplate.
HD Cable TV
Carl,
You should be aware that cable TV, especially HDTV and digital TV, is delivered overhead and contributes to the noise level as well. Cable companies are absolutely the worst about signal leakage from their systems. I have even had cable TV mess with 2 meter ham repeater signals. Usually a quick call gets the repair guy out to find and fix the problem.
Just a Minute
Marshall, just a minute. Don’t go away. I have questions.
I had not considered cable as a possible pollution source, so I’m glad you mentioned it. Another thing, my cable education is outdated and goes back to a time when fewer services were generated.
With cable telephone, television, digital, HD and back-hauling channels, I would love to have an updated bandwidth chart for modern cable. You might know a link.
Is cable FM still around?
Cable Bandwidth Chart
I am not familiar with the existence of a cable bandwidth chart. However, nearly every signal on the local cable system is transmitted in analog plus digital. So the bandwidth would depend on the number of channels and the types of transmission. The usage would have to be different on each system. The new TV band plan is available on the FCC-dot-gov site.