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 --- In digitalradio@yahoogroups.com, kd4e <[EMAIL PROTECTED]> wrote: > > > Please don't treat the radio part of these systems as a simple black > > box that replaces an ethernet wire! Please do the homework required > > to understand what happens in your radio at RF both on transmit and > > receive. In other words, do a little RF engineering in addition to > > the baseband and digital processing engineering. > > Jim WA0LYK > > There is, of course, no "magic" involved. If I may I > will again attempt a layman's perspective. > > Chaos Theory may work to our advantage here. There is > often much order embedded in what appears to be chaos. > > What *appears* to be an impossibly high signal-to-noise-ratio > to an analog system is often overcome by a sharp ear and/or > DSP processing. "Noise" as we generically label it appears > to be impossible QRM/QRN chaos unless broken down into > component parts. > > If we have good propagation such that a strong signal > *may* be received from the desired source and some > irresponsible vendor injects BPL QRM/QRN into the spectrum > then we have a known source which may be excluded via > RF signal and digital processing. > > We have nulling technologies to remove some of the > RF signal and digital to exclude non-relevant QRM/QRN. > > If we have poor propagation such that the desired > signal would already have trouble getting to our > receiver then the added BPL QRM will make a difficult > problem more so, perhaps but not necessarily impossible. > > If our transmission is in known packets and BPL > QRM/QRN successfully attacks a packet it is resent > until completed. > > As you noted, if we boost the power level of the > transmission we enhance the probability of overcoming > the BPL QRM/QRN, but we do so at the price of increased > cost and added energy -- which may be a precious > commodity in an emergency deployment. We also risk > generating our own QRM/QRN to nearby Ham & non-Ham gear. > > What am I missing? > > > -- > > 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/
