[Scan-DC] Re: Firefighter radios did not work in tunne l du r ing Metro smoke incident ·

[Jeff Krauss]

Tunnel antenna systems are complicated things.
See 
http://www.researchgate.net/publication/3156527_Measurements_and_Modeling_of_Distributed_Antenna_Systems_in_Railway_Tunnels
Maybe the antenna system was poorly designed, with large coverage gaps.
Maybe the antenna system introduces phase noise or group delay 
distortion that affects decryption capability.
Just saying "not working" may be insufficient.
Those are issues for the NTSB investigation.


At 04:53 PM 1/14/2015, Ed Tobias wrote:
>Yes, that's been reported by a number of news organizations. 
>However, if the tunnel repeaters weren't working, as has also been 
>reported, there would be a lack of comms to the command post, 
>whether encrypted or not.
>
>I spent 40 years in the DC news media and have been listening to 
>public safety radio for 50+ years. I firmly oppose encryption on 
>routine public safety channels. However, I have to wonder whether 
>news reports that are focusing on encrypted radios as a possible 
>cause of the comms problems are doing so because media members are 
>unhappy about the encryption and they're trying to make a case against it.
>
>The question that should be asked is "did the repeaters fail and, if 
>so, why?"  Maybe encryption is a factor, maybe not.
>
>Ed
>
>Sent from my iPhone
>
> > On Jan 14, 2015, at 3:34 PM, "Thomas J. Dalrymple" 
> <tjdalrymple at gmail.com> wrote:
> >
> > I heard this on WTOP around 2pm, but have not found it on their 
> website yet.
> >
> > Encrypted radios were not working in the tunnels, and firefighters
> > resorted to runners to deliver communications from the site to
> > firefighters outside.
> >
> > Tom D.
> >
> >> On Wed, Jan 14, 2015 at 10:02 AM, Ed Tobias <edtobias at comcast.net> wrote:
> >> The problem, (at least one of them), seems to have been that the 
> in-tunnel repeaters were out of service. That would have made it 
> difficult, if not impossible, to communicate from tunnel to command 
> post or along long stretches of tunnel.
> >>
> >> Montgomery used to send a Btl Chief to the Command Center at 
> Metro Hq to help coordinate incidents. Not sure if they still do or 
> if DC does that.
> >>
> >> The Rail70x units are, I believe, MCFD officers with specialized 
> training for Metro incidents.   Don't confuse them with NCR70x 
> units, who carry radio caches for use in major incidents involving 
> multiple jurisdictions.
> >>
> >> Ed
> >>
> >> Sent from my iPhone
> >>
> >>> On Jan 13, 2015, at 10:29 PM, Jeff Krauss <jeff at krauss.ws> wrote:
> >>>
> >>> After viewing the Fox5 piece by Paul Wagner, I'm sure you're correct.
> >>> He said that the units in the tunnel couldn't communicate with 
> the incident commander at street level.
> >>>
> >>> Which means that the DCFD command structure was deficient.
> >>>
> >>> If I recall, the Montgomery County FD procedure is to assign a 
> "Forward Incident Commander" (they don't use that term) at the 
> stationmaster's kiosk, whose job includes communications between 
> units in the tunnel and the command post upstairs.
> >>>
> >>> Also, when Montgomery County has a Metro incident, I hear units 
> come up on the air identifying themselves as "Rail 704" and similar 
> callsigns.  Not clear whether they are County FD employees or WMATA 
> employees.  At least some of them seem to carry caches of radios to 
> assist in radio communications between the fire department and 
> Metro dispatchers.
> >>>
> >>>
> >>>
> >>> At 08:07 PM 1/13/2015, djoneses wrote:
> >>>> I would think that this quote from the Fox5 story answers your question:
> >>>> "firefighters used line of sight communication in the 
> tunnel."  Presumably
> >>>> that means that simplex i.e. line of sight channels were used.
> >>>>
> >>>> -----Original Message-----
> >>>> From: Scan-DC [mailto:scan-dc-bounces at mailman.qth.net] On Behalf Of Jeff
> >>>> Krauss
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