> -----Original Message----- > From: digitalradio@yahoogroups.com > [mailto:[EMAIL PROTECTED] Behalf Of expeditionradio > Sent: Sunday, October 01, 2006 7:39 PM > To: digitalradio@yahoogroups.com > Subject: [digitalradio] BPL-Busting Modes/Techniques > > > BPL-Busting Modes/Techniques > > The Digital Voice formats presently in use by hams are not designed > to be resistant to QRM from BPL (Broadband over Power Lines). The > OFDM digital voice methods require a much higher S/N than SSB. > > In fact, most of our present digital and analog modes are not > resistant to BPL intereference. However, such BPL-resistant or > BPL-Busting digital techniques could be designed into new digital > communication formats for HF and VHF.
Here is what ARRL's Ed Hare, W1RFI, had to say about this subject (cross posted from the "BPLandHamRadio" Yahoo group with Ed's consent). In particular note the comment about "white space": Quote: > If BPL were simply a number of static carriers, > digital-signal processing could, in theory, remove them. > > Unfortunately, they are modulated, and generally > modulated fast enough that the carrier itself is > only a small portion of the energy. The rest is > ever changing digital information which is, to > other systems, noise. It will appear as noise > and the techniques used to remove carriers cannot remove BPL. > BPL is typically 40 to 60 dB greater than the > ambient noise in an area. As noise, it is uniform > vs frequency. If DSP could copy signals 60 dB > below uniform noise, we would be using it right > now to pull signals 60 dB out of our present noise levels. > BPL is designed to be spectrally efficient, pushing > the Shannon limit on the amount of data that can be > sent on a given communications channel vs frequency > and noise. There really is no "white space" into which > other communication can be interleaved. > The BPL industry cannot even develop a standard > to prevent different types of BPL systems from > interfering with each other, on a channel that they > fully control. How can we expect that radio users > can develop techniques to overcome it? > And even it it were possible to sneak a bit of > information through on the channel occupied by BPL, > what will happen the next time a different > unlicensed use also uses the same channel? > The premise that licensed operation must constantly > adapt to accomodate unlicensed use is flawed, which > is exactly why the FCC has rules that place the burden > of resolving interference on the unlicensed source. > If the FCC had vigorously enforced its rules, we would > not be seeing Part 15 noise nearly as rampant as it is. > Ed Hare, W1RFI > ARRL Laboratory Manager Unquote Rick Karlquist N6RK Rick Karlquist N6 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/
