On 17/03/2014 13:14, Jerry Stuckle wrote:
On 3/17/2014 3:45 AM, Jeff wrote:

7dBm is an absolutely colossal signal for a TV set. Even 0dBm is an
absolutely colossal signal!

Not in the United States. It was the minimum that the cable industry
provides to the TV set.

We are talking a signal 4.25Mhz wide signal, not SSB or CW.


dBm is not a bandwidth dependant measurement such as CNR which is.
Putting +7dBm into a tv receiver is madness, it would cause severe
overload and inter mods. +7dBm is 50mW and that equates to about 61mV in
a 75 ohm system which is an enormous signal.

Jeff

Wrong. TV's are made to handle at least 20 dbm. And cable tv companies
must deliver at least 10 dbm to the premises.

TV signals (at least in the U.S.) are not measured by CNR - they are
measured by dbm. CNR is not important because the bandwidth does not
change.

Your insistence on using CNR shows you know nothing about how the
industry measures signal strength.


I have not insisted that CNR was used, it that was another poster who
mentioned CNR, what I was pointing out was the error that you made in
taking the 43db CNR value that was posted and then going on about
dbMmlevels.

I also dispute that televisions are made to handle +20dBm; that is 100mW
far in excess of what a tv tuner can handle without overload!!!!

+20dbmV may be but not +20dbm.

Jeff