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noaa VHF radio as the sole EAS primary

geary said:
nmoore6676 said:
LA_Guy said:
No.

First off, there are too many coverage gaps with NOAA weather radio-and many of the sites have no back up power. Second, most of the sites are fed by 3 kHz telco loops-some with no isolation transformers (which is why you hear hum on many NOAA stations).

Finally, most of the NOAA gear is now over 20 years old and is of vaccuum tube vintage. Many of the sites are also maintained by 'two way' technicians.

What makes a whole lot more sense is a satellite/IP system with longwave running DRM for backup. The govt. could recycle some of the dormant Loran C sites and cover the entire USA with a decent groundwave signal 24 hours from around a dozen LF transmitters.
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Here is a real workable idea. Hard wired copper lines spanning the nation. Worked real good back in the good old days of network radio and television. The using other system such as VHF radio and LF radio is just redundancy and a fail safe system of any flavor includes redundant elements.
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I take it no one told you the "1st mile" of this National test was phone couplers to the PEP stations? Or did you thing those who got the "pristene" 300-3K audio bandwidth (if they got any at all) did it with equalizers?
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Phone couplers never entered my mind. What I was talking about was dedicated copper pairs such as were used for the national networks, NBC, CBS, ABC, MBS and also used to send audio from studios to transmitter. Couplers were not a part of the chain and the lines were equalized for high fidelity. Of course having full audio spectrum lines for this purpose wouldn't be required but back in the day even the ordinary unequalized pairs used for sporting event coverage produced intelligible though somewhat tinny sounding audio.
 
I've been thinking about it since the test, and NOAA has come up as a PEP, so has a Ku satellite. Then I realized the solution is right in front of us for a nationwide PEP. Sirius/XM.

I can get the signal on a little puck on my car and also on the roof of my house. There has been a foot of snow on top of that puck, and a driving snowstorm itself, plus rain, thunderstorms and the like. Guess what? I can still hear Howard just fine. Scale that up a bit for a "fixed dish" installation, using an 18" pizza tray DirecTV style dish and I'll bet that the signal will go thru anything. Hell, I had the puck inside the top floor of my house and still managed to get 1 bar on the signal strength meter. No, I'm not even anywhere close to a terrestrial repeater, this was direct from the bird.

The receivers already exist. The dishes/antennas already exist. Each station gets a receiver tuned to a special EAS only channel, which wouldn't take up any bandwidth unless it is being used. The receiver can pick up both Sirius and XM, so there is some redundancy in what satellites can be received. They're also the highest powered birds up there for any civilian uses, so they will cut through the snow and rain, unlike a normal Ku band dish.

There are multiple uplink stations for both services. I'm sure another one could be set up right from FEMA as well.
 
Now you guys are on to something. How about a FEMA channel for cable and satellite. It could show classic Irwin Allen films and similar productions in that genre. All disaster all the time. ;D
 
nmoore6676 said:
Now you guys are on to something. How about a FEMA channel for cable and satellite. It could show classic Irwin Allen films and similar productions in that genre. All disaster all the time. ;D
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Ah, that would be the CONgress channel..
 
TomZ said:
nmoore6676 said:
Now you guys are on to something. How about a FEMA channel for cable and satellite. It could show classic Irwin Allen films and similar productions in that genre. All disaster all the time. ;D
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Ah, that would be the CONgress channel..
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No they would be on the Three Stooges Channel, nyuk, nyuk nyuk!!
 
Just think! Mel could charge stations 5 bucks a radio per month for the privilege and claim them as subs to his stockholders (the name of their game) while pounding his chest that HE is the one that fixed the problem. With another 1500 or so potential subs, I'd be all over it if I were him!
 
WNTIRadio said:
I've been thinking about it since the test, and NOAA has come up as a PEP, so has a Ku satellite. Then I realized the solution is right in front of us for a nationwide PEP. Sirius/XM.

I can get the signal on a little puck on my car and also on the roof of my house. There has been a foot of snow on top of that puck, and a driving snowstorm itself, plus rain, thunderstorms and the like. Guess what? I can still hear Howard just fine. Scale that up a bit for a "fixed dish" installation, using an 18" pizza tray DirecTV style dish and I'll bet that the signal will go thru anything. Hell, I had the puck inside the top floor of my house and still managed to get 1 bar on the signal strength meter. No, I'm not even anywhere close to a terrestrial repeater, this was direct from the bird.

The receivers already exist. The dishes/antennas already exist. Each station gets a receiver tuned to a special EAS only channel, which wouldn't take up any bandwidth unless it is being used. The receiver can pick up both Sirius and XM, so there is some redundancy in what satellites can be received. They're also the highest powered birds up there for any civilian uses, so they will cut through the snow and rain, unlike a normal Ku band dish.

There are multiple uplink stations for both services. I'm sure another one could be set up right from FEMA as well.
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You'd probably never get a signal from the satellite on those services, unless you are out in the hinterlands with a clear shot to the birds.
This guy calls them "Terrestrial Broadcasters with Satellite Fill-In":
http://www.cedmagazine.com/articles/2006/11/are-sirius-and-xm-radio-really-terrestrial-broadcasters?

I'd hate to think what happens to those high-powered Terrestrial "Repeaters" when the power goes off in the apartment building or office tower they lease space from.

Also, the individual channels of programming are not sent as separate carriers. They are sent as data within multi-channel carriers, all mixed together. You'd need to shut down one stack of, maybe a dozen channels of programming, to put up one alternate FEMA channel. Otherwise, you'd need to uplink it from a common uplink. The 12.5 MHz bandwidth of the satellite is already packed, full time.

FEMA has an existing network of HF stations, usually located at Emergency Operations Centers in major towns and cities. They use Automatic Link Establishment (ALE) links to establish communications on whatever frequency is deemed appropriate for propagation at the time. Those links can operate in a variety of modes, so Digital Audio (like DRM) would work fine for announcements.
There is an HF relay at Golden, Colorado. Utilizing a combination of short-range and long-range (different vertical take-off angles) antennas could allow several other sites to act as backup relays, or to create regional networks, as needed.

FEMA has commented to the FCC on the Broadband Over Power Lines (BPL) interference potential, though. Since the FCC didn't seem too concerned, maybe the FEMA sites would have to be declared "Quiet Zones" for BPL, at least on some frequencies. That might make for some happier Hams and Shortwave listeners nearby, too. ;D
 
I'm 60 miles outside of NYC, with not a terrestrial repeater in sight, and can get the signal fine from the satellite. My receiver (and research on the licenses for the repeater) shows that the full signal is coming off the bird. Why couldn't it easily be picked up on an urban rooftop? Especially if you take the usual puck and size it up to an 18" dish with a lot more gain, I really don't see why this wouldn't work. Most stations have a regular satellite dish somewhere with a clear shot to the sky anyway.

The data streams are fluid. It would be easy to set up a FEMA only channel, with about 16kbps on their codec that could come in unlocked to all receivers, just like the preview channel. The 16kbps would come out of the dynamically encoded streams. Shave 1kb off 16 channels when it is active, or .1kb off of 160 channels. However it is done, the way they are encoded, if there's no audio, there's almost no bandwidth being used. So only on those rare occasions would it use their bandwidth.

Make it part of their obligation to be the nationwide PEP.

Use the HF as a backup. But I would think that ALE/DRM etc could easily be jammed by a few terrorists with a few HF ham radios.

Or, how about instead of BPL, the signal is sent as a 150hz carrier on the powerlines themselves?
 
Yeah, I understood you saying you weren't getting it from a terrestrial repeater...but most city dwellers do.

They'd still have to stuff the signal in to the data stream at the XM and Sirius origination points, though. That would not be hard to do. Since SDARS has to do EAS anyway, it wouldn't hurt to make them one of the primary links. Don't know if I'd want them to be the ONLY one though, since satellites could be jammed as well.

The HF links could jump around to different frequencies to avoid jamming, but would be useless to anyone who is not set up to operate in that (FEMA/EAS) network.

As for LW radio, I doubt that most radios could receive it, unless it was almost "local", due to the Part 15 non-compliant noise.
 
WWVB is receivable almost 24 hrs a day in most of the CONUS.
But it might take some time to get a text message out unless they bumped up the data rate a bit.
 
I don't think we should use any one system to relay EAS. I think we should look at putting it up on several different technologies, and requiring stations to pick any two. Some options:

- Satellite radio.
- An audio-only program stream on a TV satellite feed.
- The Internet. (basically, what's happening for CAP)
- NOAA weather radio.
- A LP station.

Each of these schemes has its positives and negatives. Some are better for reliability in normal times and for audio quality; others are less susceptible to interference from natural disasters, intentional jamming, and everyday noise.
 
boiseengineer said:
WWVB is receivable almost 24 hrs a day in most of the CONUS.
But it might take some time to get a text message out unless they bumped up the data rate a bit.
Click to expand...

IIRC, their data rate is something like 60 Bps.
 
The Feds tested LF AM with 50 kW on 179 kHz. mid-70's on WGU-20. This was a direct to consumer receiver system with automatic alerts. If built, there would have been 8 or so of these around the country, triggered by two master stations on 61 kHz. The inexpensive receivers would have been embedded in all manor of devices.

I've come to think that's a pretty good way to distribute EAS too.
 
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