Your basically talking about signals you can hear well, i.e. well beyond the minimum signal to noise ratio's. Also with analog SSB voice the crest factor is very large. That is, one person is just speaking a hard consonant while anothers voice is just fading to nothing. Therefore the power inpinging on your antenna varies widely depending whose voice is causing the most power output at any given instant.
Even though the BPL signal may be somewhat predictable it will still mask the signal you are looking for. You can not recover what is lost. You may miss the start of a pulse, the end of a pulse, or even a whole pulse. Random noise is not at a constant level even though your ears may think so, that is why the corrections of signals work. However, if the signal is far enough down so that it doesn't even reach the valleys in the noise, then there is no signal present to be retrieved. Haven't you ever heard a signal being suddenly and totally masked by QRN/QRM? I don't mean just hard to hear but when your trying to copy an S2 signal and someone tunes up with a 60 over S9 carrier? There is no way to ever recover the information lost, it just isn't there. Jim WA0LYK --- In digitalradio@yahoogroups.com, kd4e <[EMAIL PROTECTED]> wrote: > > > I may be wrong but I beleive your theory doesn't assume that the RF > > energy at your reciever's antenna is not additive. In other words, > > the signal from the transmitter you want to hear and the interfering > > signal do not add together. You can only discern the strongest > > signal. An example is, that if you put a carrier on the air and I > > receive it at S9 and then someone else puts a carrier on the exact > > same frequency but it only arrives at S8, I'll never know it is there. > > > > Therefore, when you remove the interfering signal, you also remove any > > possibility of retreiving information from the signal you want to > > hear. Consequently, you will never have a coherent signal to decode. > > It will always have missing information. > > > > Any other assumption means noise, especially random noise, would not > > be a problem, and that you could always subtract a signal from it. > > Every mode I know of, digital or analog, has a minimum signal to noise > > ratio that is required to decode it. > > > > Jim > > WA0LYK > > SSB is carrier suppressed and CW is all carrier. > > In either case several stations may transmit on > the same frequency and I can hear at least pieces > of many of them. > > What you are describing sounds like FM capture effect, > I am not certain that it applies to other modes. > > Digital modes have steadily improved in the capacity > to extract data packets from further and further down > into the noise floor. > > In my construct we are dealing with a situation where > it is possible to receive a signal in the absence of > the BPL QRM/QRN so the non-BPL exacerbated SNR would > be at a reasonable level absent the BPL. > > Since BPL-generated QRM-QRN is somewhat predictable > it would seem reasonable to postulate that it may > be removed or mitigated via a variety of methods. > > This is not to say that I believe BPL is anything > other than a dumb idea, financially or technologically. > It is bad for stockholders, bad for emergency > communications, and bad for Hams and SWL's. > > That said, the level of power line, cable line, > private resident, and business QRM/QRN her north > of Florida is horrific. It renders the AM-broadcast > band nearly unusable in places -- in direct violation > of law and regs. Enforcement action is unlikely. > > One wonders if the hidden agenda of BPL and ignoring > other QRM/QRN is to drive Hams off significant segments > of spectrum in order to make it available to commercial > interests. > > -- > > Thanks! & 73, > doc, KD4E > ... somewhere in FL > URL: bibleseven (dot) com > Need a Digital mode QSO? Connect to Telnet://cluster.dynalias.org Other areas of interest: The MixW Reflector : http://groups.yahoo.com/group/themixwgroup/ DigiPol: http://groups.yahoo.com/group/Digipol (band plan policy discussion) Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/digitalradio/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/digitalradio/join (Yahoo! ID required) <*> To change settings via email: mailto:[EMAIL PROTECTED] mailto:[EMAIL PROTECTED] <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
