Patrick, You do realize you're going to need to buy out a stationery store to get enough supplies for your FM QSLs if you get serious about FM. I do poorly with skip here and I still have about 300 Es receptions. If you get real patient, you can also use meteors.
Mike Hawkins On Tue, May 19, 2015 at 9:21 PM, Patrick Martin <mwd...@webtv.net> wrote: > Thanks Scott. I kind of follow it. 88.1 is interesting here, as when I > first tune to it on the Sony, I get analog KWAO Ocean Park WA, but within > seconds, HD signal KQOC Gleneden Beach OR takes over the frequency and > locks the HD, totally eliminating analog KWAO. Infact on any portable on > non HD radio, all I get is KWAO. I was quite taken back when the Sony gave > me KQOC! The same is true with 96.5. When I first tune it in, I am getting > analog KCYS Seaside, with within seconds again (depending of the signal), > KJAQ Seattle locks the frequency. At that point hearing KCYS takes work and > I have to turn the yagi to knock KJAQ down to get local KCYS. It is odd > sounding to me. Also sometimes when I land on 96.5, I immediately get the > KJAQ ID, before I get the station! So the audio is KCYS (also Country) and > I am getting the ID RDS from KJAQ. I guess that is what you have > explained, but it is different to say the least! So the sub channels I am > hearing, when they pop in at 1% of th > e analog signal. I thought I might get some HD from Seattle as I know > that years ago when the powers were a lot less (60s/70s), some ran a couple > KW or so from Cougar Mt and I got them in full FM Stereo. One I wanted was > KNHC 89.5, but so far no luck. even in analog. I used to get it years ago > off and on, but I did have a better yagi. I may stack two FM6's. I'll say > one thing, HD FM is a different thing. It will be interesting with E Skip. > I guess I could get the RDS ID without getting the audio from the station > too, depending on how stable the signal is. Being away from FM DX for 25 > years, the dial is sure a lot different than it was. > > Patrick > > Patrick Martin > Seaside OR > KGED QSL Manager > > > Date: Tue, 19 May 2015 14:19:15 -0400 > > From: sc...@fybush.com > > To: irca@hard-core-dx.com > > Subject: Re: [IRCA] IBOC Hash AM vs FM OT question > > > > For those who are interested in the technical reasons why Patrick > > doesn't get the same kind of adjacent-channel hash that those of us in > > urban areas do, read on. For those who don't...another thread will be > > along shortly with convention news ;) > > > > -- > > > > As far as propagation is concerned, there is nothing at all magical > > about the digital signals that flank the analog FM signal to create HD > > radio on FM. The ionosphere doesn't care whether it's analog or digital > > modulation. If a signal is (a) strong enough to be received and (b) > > doesn't have something stronger sitting over it, you'll get it. If > > either of those factors doesn't exist, you won't. > > > > So: it helps to think of the digital signal as something separate from > > the analog. If you're getting KUOW in HD, for instance, you're really > > getting: > > > > --94.6 --- > > > > KUOW lower digital carriers (on the same piece of spectrum used by an > > analog 94.7 signal) > > > > --94.8 --- > > > > KUOW analog signal (centered at 94.9) > > > > --95.0 --- > > > > KUOW upper digital carriers (on the same spectrum used by an analog 95.1 > > signal) > > > > --95.2 --- > > > > Depending on the station's technical setup, the digital signal may > > literally be completely separate from the analog. At WXXI-FM, for > > instance, our digital signal uses a separate transmitter, separate > > transmission line and separate antenna bays interleaved with our analog. > > It is possible (albeit not currently legal) for us to completely turn > > off our analog transmission chain and run only the digital carriers. If > > you were listening on an analog radio, you'd hear nothing on 91.5 (or > > maybe even be able to DX something else on that frequency), but an HD > > radio would detect the digital carriers and still give you WXXI-FM when > > tuned to "91.5." > > > > The digital carriers operate at much lower power levels than the analog. > > Initially, digital operated at just 1% of analog, or 20 dB below carrier > > (-20 dBc). More recently, the FCC has started allowing stations to use > > higher power levels of 4% (-14 dBc) or even 10% (-20 dBc) of analog. > > > > So using KUOW as an example, let's say it's still -20 dBc. That's 100kW > > in analog and 1 kW in digital. If you're in metro Seattle, that 1 kW > > digital is plenty to still ride right over anything else that might be > > coming on the adjacent channels of 94.7 and 95.1. If you're way down in > > Seaside, though, those 1 kW digital signals are DX: point a good antenna > > right at Seattle and you might get them strongly enough to decode, IF > > there's nothing else in the way on those frequencies. Point the antenna > > away from Seattle or disconnect it and you won't hear much of anything, > > as would be the case with ANY signal of 1000 watts from 100+ miles away. > > > > This leads to a bunch of interesting DX scenarios when you start to > > break it all down: > > > > For instance - let's say that you were a little closer to your > > semi-local on 94.9, enough so for it to be an un-nullable pest. But > > let's also say that your local 94.9 is analog-only. So you might have a > > spectrum that looks like this: > > > > 94.6 --- > > > > KUOW lower digital sideband, weak but with nothing else in the way > > > > 94.8 --- > > > > Your local analog 94.9, loud enough to overwhelm KUOW's analog > > > > 95.0 --- > > > > KUOW upper digital sideband, weak but with nothing else in the way > > > > 95.2 --- > > > > On an analog radio, all you'd hear is the local when you tune to 94.9. > > But when you tune an HD radio to "94.9," if it can hear those upper and > > lower sidebands, it will ignore the analog in-between...and so you might > > hear your local 94.9 in analog for a few seconds and then, when the HD > > decodes, you'll hear KUOW instead, because while your radio says "94.9," > > it's really looking for signals above and below 94.9 to decode. > > > > There are all sorts of permutations on this that can happen when the > > dial is more crowded. It's easy, for instance, to think of scenarios > > where the spectrum is clear for a distant analog signal but its HD > > sidebands are overwhelmed by locals. For instance, I can easily hear 105 > > kW WTSS 102.5 Buffalo in analog from about 70 miles away - but its > > 1050-watt digital carriers are completely obscured by locals WVOR 102.3 > > and WLGZ on 102.7. If either of those locals goes off, there's WTSS in > > digital, because that bit of spectrum is suddenly open. > > > > Does that help make some sense of all of this? > > > > s > > > > _______________________________________________ > > IRCA mailing list > > IRCA@hard-core-dx.com > > http://montreal.kotalampi.com/mailman/listinfo/irca > > > > Opinions expressed in messages on this mailing list are those of the > original contributors and do not necessarily reflect the opinion of the > IRCA, its editors, publishing staff, or officers > > > > For more information: http://www.ircaonline.org > > > > To Post a message: irca@hard-core-dx.com > > > > _______________________________________________ > IRCA mailing list > IRCA@hard-core-dx.com > http://montreal.kotalampi.com/mailman/listinfo/irca > > Opinions expressed in messages on this mailing list are those of the > original contributors and do not necessarily reflect the opinion of the > IRCA, its editors, publishing staff, or officers > > For more information: http://www.ircaonline.org > > To Post a message: irca@hard-core-dx.com > > _______________________________________________ IRCA mailing list IRCA@hard-core-dx.com http://montreal.kotalampi.com/mailman/listinfo/irca Opinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officers For more information: http://www.ircaonline.org To Post a message: irca@hard-core-dx.com
