Storm aftermath - were you out of service? [Telecom]

Bill Horne wrote in news:DrSdnZ8slL59-tvUnZ2dnUVZ snipped-for-privacy@speakeasy.net:

Cable

Stratham, NH

50 hours electrical, about 70 hours phone-TV-HSI

Comcast

Yes; electrical power came back first, but cable is routed differently from the electrical feeds, so it took another day for the electricity to be restored to the areas with the cable amplifiers, etc.

Verizon wireless phones; VHF to local FD was available (to us as VFD members) in case of emergency.

Fairpoint (formerly) POTS customers did not have much better luck with phones, since the batteries at the SLC installations kept running down. More and more, POTS is no longer POTS.

The utilities, especially Unitil (electric) are still working around the clock, since the outages were extensive.

Bill

During our summer storm season a citizen on a road near me ran a ten gage cord over the street between two power poles and hooked it into the Controlled Environment Vault (CEV) generator connection. He had connected it to an outlet on the generator that is also connected to his home through a transfer switch. The cop shop types had to be persuaded by us hose jockeys to not force him to take it down. His arrangement worked very well. It kept the telephones working to a recreation center that is used as a special needs shelter for asthmatics and a police sub station together with the rest of the neighborhood. The sub station does all its emergency communications by radio but the Recreation Centers Radios are portable amateur radio stations set up when needed. I'll never figure out why the cop shop feels they have to mess with stuff like that. Good judgment would seem to suggest that the basic rule of the Wicca religion; "And it harm none, do as you will"; should apply to such situations.

This brings up an interesting point. I note that Providence Police Dept. has bought the Motorola radios for 800MHz trunked systems hook, line and sinker.

Curiously the repeaters for the system are all over the city, supplied by the commercial power grid with no backup power supplies at all.

So if there's ever a citywide power failure they're screwed.

Got to love poor planning. Not to mention that their MESH data network will go belly up too.

Great, the service was kep up, but what would have happened if his hookup had damaged the CEV or sent unfiltered noise over the line which could have damaged the cards in the CEV?

Bill Horne wrote in news:DrSdnZ8slL59-tvUnZ2dnUVZ snipped-for-privacy@speakeasy.net:

In Nova Scotia, the ice seems to have turned to harmless rain.

On a relevant note, however...

The NS power service was privatized a decade or so ago. Before that time, the powerco routinely cut trees and branches that threatened rural power lines and cleared underneath them. After privatization, that seems to have stopped nearly completely, at least in my largely rural county.

The result is that every major wind-, wet-snow- or ice-storm produces wide-spread power outages. Then, repair crew respond promptly. I can only guess that the out-of-pocket cost to the powerco is less to put repair crews out in nasty weather than it is to put maintainance crews out all the time in good weather, but at the expense of wide and sometime prolonged outages where people increasingly depend on electricity for water, heat and cooking. "Externalize internal diseconomies", eh? MBA-ese for "Let somebody else eat it."

The POTS and cable come off a better -- notably fewer outages -- because (I'm guessing) the phone and cable lines are lower on the (same) poles.

FWIW,

I'm in Nashua, NH, in a heavily settled reagion. Power was out for

4 1/2 days. Although all of the areas around me had power, we were affected by a lot of downed trees, and it took a while for all of the power lines to be put back in place. At first I thought we were being overlooked, until I found out where the damage was and how extensive it was.

Telephone service to my home worked for two days, then died. The probable cause was that the backup battries in one of the telephone "boxes" ran down. Service was restored when the power came back on.

I saw a portable power generator sitting at the bottom of a pole with an extension cord running up to a box. It was probably put there for either Cable TV or for Fiber. I don't have either, so I don't know what effect it had.

Unfiltered noise would damage the cards? Anyone else here see that as a real possibility? I've seen the portable generators that Verizon uses at CEVs if they can withstand the power provided by those they should be able to take anything.

Just trolling for a quarrel I guess.

Bill has already warned you that I'm no fan of trunked radio for emergency services work ([BTW,] cell phones are a form of trunked radio). One of the recently discovered problems is that the vocoder used in digital trunked radios will transmit the loudest sound present and filter out the rest, [so] your [gasoline powered] roof saw will be heard, but what you are reporting to command ... will not be heard.

Then there is the issue of robustness of the system as a whole. We had a shrew chew up a fiber optic cable and put the entire county radio dark for several hours: all of the old jokes about the difference between the demonstrator software and what actually gets installed can be easily reworded to apply to trunked radio systems. [The vendor] will tell you all the marvelous stuff that the system can do for you, but when it comes down to signing a contract, what they will *guarantee* it will do for you is always much less.

So have I, I have hooked them up to CEVs and RSUs, and they are not just your run of the mill generators. In most cases the batteries will filter most noise, but with a home type generator anything can happen. I have a Honda generator that I bought many years ago, and it works really [nicely]: it is hooked up [to] a bypass so in a power failure I can run most of the house on it. [After] having solar installed last year I have gone though [two] brown outs last summer with no losss of power from the batteries.

Why would that vocorder issue be specific to "trunked" digital systems rather than just any digital encoding?

And similarly, would it be a problem for analog trunked systems? Yes, there are quite a few.

That's simply an issue of non-redundancy. If there was a secod fiber path, the signals could have been rerouted either automatically or within a few minutes.

The same thing would have happened if the system was designed with just a 250 pair set of copper wires and no redundant loop.

Danny

Read the National Fire Protection Association (NFPA) standard on Fire Department Communications and then find me one trunked radio system that is actually in compliance. If you find one I will be appropriately amazed. The Nun that strove in vain to teach me grammar said many times that "should" and "should be" were "conditions contrary to fact". She said that meant that the moment you said "should", "won't" was implied: likewise, "should be" implied "wouldn't be".

Of course, these new communications systems should be robust and redundant. But building them that way would reduce the profitability of the project and as any capitalist will tell you profit is god. If I remember correctly you are in the business, so you ought to know these things much better then I do. The only way you will get a fully redundant system is by paying an independent radio engineering firm to audit the project every step of the way. I've never heard of that actually happening. Have you?

On the vocoder issue you are correct that it is not unique to trunked radio but rather to digital radio in general. The fact is that no one is currently installing analog trunked radio systems but analog fixed frequency installations are still rather common because they are backwards compatible with existing mobile and portable equipment and cost much less.

Here's a quiz question for you: why has the FAA clung to AM radio, and it's successor SSB, and disdained both digital and FM for aircraft communication? I do not know of my own direct experience (not having ever been involved), but people I trust on such issues tell me that it is because when two aircraft double (i.e., talk at the same time), parts of both transmissions can usually be made out by the air traffic controllers. They may need fills but they can generally tell if one of those transmissions was a declaration of emergency. With digital and analog FM radio that simply isn't so.

It's not, but just about all digital voice land-mobile systems are trunked. I have never seen one that is not.

No, it's not.

Right, but the beauty of conventional land-mobile radio is that it does not require any infrastructure. Even if the repeater is down, everyone can move to a simplex frequency and talk with one another if they are within range.

Current trunking systems do not allow this, although there are military digital radio systems with reconfigurable networks that do.

--scott

There actually ARE some digital communications modes in which two talkers can step on one another and both be received properly. I believe this even includes PSK31 as well as Hellschreiber.

--scott

I know a lot that claim to be in compliance....

NYC's system is way behind schedule and has missed lots of pricing targets, but it's getting there. Part of the deal is that it's a combination of traditional vhVHF and UHF, with crossover to both trunked and untrunked 800. Oh, and throw in data capability on the city's own WLAN (or would that be a MLAN) with mesh tranceivers on lots of gov't buildings and lamposts - which also allows for voice.

Again, way, way, behind schedule, etc., but there are enough professionals pushing it behind the scenes that it's getting there.

That's what I've read and heard as well, but I've got to wonder about it a bit. In theory FM has a "capture" issue where the stronger signal completely wipes out/steps over the weaker one, blocking anyone from hearing that second pilot who's callign for help.

But when I listen to standard FM broadcasts using regular consumer equipment, I often hear both the powerful, nearby station, and also a weaker one.

It's possible that the capture issue is, indeed, real and that I'm only hearing, say, five percent of that secondary signal compared to what I'd hear if it was AM. (Pretty much by definition I don't know what I'm missing...).

I'd love to hear from anyone with direct experience with this stuff.

Eyup. Ye Olde "get a half dozen folk in pickup trucks, station them every couple of miles on the road, and have them play 'telephone' as needed".

(replace "pickup truck" with police cars, ambulances, fire engines, utility workers, etc., as available).

- It actually works reasonably well provided you've got the people and they've had a bit of practice.

It's part of the spec for NYC's system as well as the larger, and cross-linked, NY State-wide arrangement. I don't know how far they are into implementation.

(Various audits of the the NYS one have been devastating).

In our case just talking out less than a half dozen repeater sites would darken the entire trunked radio system in Providence. I know where three of them are and it wouldn't be such a stretch to find the other three. There are five hills in Providence so there's one for each and then a final at HQ.

But as I said, none of the repeaters have backup power.

It seems to be a common theme with public service agencies. The city of Providence has the largest police and fire departments in the state.

The police department got wined and dined by HTE (A criminal info system vendor) but HTE wouldn't interface with the Attorney General's Rhode Island Criminal History (RICH) system. All the other departments used IMC and IMC could scale for Providence but they wouldn't hear of it.

This was back under the watch of Urbano Prignago as Chief. Good friend of mine was the IT director under Prignano and he used to tell me the horror stories of corruption in the department.

Now we have supposed professionals (Dean Esserman), but they still buy the Motorola line.

Sounds like you're listening to an intermodulation product generated by your regular consumer equipment's internal preamp. Much of today's "regular consumer equipment" has horrible front-end filtering, but really sensitive detectors, which allows you to tune intermod all across the dial.

-GAWollman

The LAPD radio system is the best known example of a non-trunked APCO-25 format digital system.

Santa Clara County (Ca) Sheriff uses APCO-25 on 3 of their VHF channels, but not on all frequencies. They use it on the west side dispatch, but not on the primary dispatch channel. They also use it on the detective channel, and court security.

San Jose, Ca has at least one APCO-25 channel within their UHF conventional system. I believe it is used by the narcotics unit.