April 2012 Inbox
Friday, April 13, 2012 | Comments
LTE, P25 Public-Safety Networks Contribute to RNC Communications, Security
FirstNet Listens to States in RFP, Offers Vendors ‘Golden Opportunity’
Following are comments we’ve received from readers about recent online and print news and articles. If you’d like to comment on an article, email edit@RRMediaGroup.com.
In response to “APCO Asks for T-Band Narrowbanding Break, L.A. and Chicago Seek Guidance” from April 16
I would like to add my comments on the FCC mandated narrowbanding. Just what separation distances are coordinators and the FCC going to use when adjacent channels become 12.5 kilohertz and assignments are made with this doubled number of channels?
Most newer radio equipment can be reprogrammed to the 12.5-kilohertz channel spacing and lower modulation bandwidth (deviation) but will suffer degradation if there are new assignments of high-power base stations or repeaters in the area. My experience with 25-kilohertz spacing is that adjacent frequencies cause
interference at distances of up to 75 miles away (mountaintop to mountaintop or other line-of-site situations). I have used the 12.5-kilohertz splits, and even with the lower modulation, have had interference problems.
Maybe if all industrial/business users were able to afford brand new digital radios specifically designed for this narrow spectrum, then there might not be as much concern. However, business organizations do not have the benefit of deep pocket federal assistance/grants or taxpayer money to purchase new systems and the infrastructure needed to support the narrowing channel bandwidths. Not
only is the T-band spectrum feeling the financial pinch, but those of us using VHF and UHF for public safety and business uses do not have the financial resources to throw away perfectly good older radio equipment that can’t be reprogrammed to the lower modulation requirements and then have to add more radio equipment to recover the lost areas of coverage.
Again, the assignments of new stations that are only 6.25- and 7.5-kilohertz away from present assignments are already causing interference issues and more efforts to have coordinators resubmit licenses for new frequency assignments. I have VHF repeaters on mountaintops with only a few kilohertz separation on the input side from digital stations 25 – 30 miles away. Even with narrowbanding, the audio is in the band pass and blocks the repeater. In some parts of the country, we are blessed with the high hills to extend our coverage with a single repeater, where as in the flat lands, this can’t be accomplished without the use of multiple repeaters and high towers. I just do not see the advantage of the narrowbanding and the future of narrowing the channels again unless the technology keeps up and the funding is available to all users of the spectrum.
In response to “Your Guide to the UHF T-Band Giveback “ from March 14
In your last two articles, you refer to additional channels being available in VHF and UHF as a result of narrowbanding. I don't know where you are getting your information, but it is misleading to say the least. All the 12.5-kilohertz splits in UHF and 7.5-kilohertz splits in VHF have been loaded, at least in the New York/Philadelphia corridor and surrounding areas. I venture to say the same is true in all the metropolitan areas.
Here's a question to which I haven't seen any answer. With a federal government so far in debt and budget, grants and services support cuts coming, how can anyone say the feds will ever fund this? Everything is pie-in-the-sky at this point. Who is to say any money from the auction of channels will not be diverted to other needs? I am willing to bet that in eight to 10 years this whole thing may die because of lack of funding.
In response to “9 Insights into Spectrum Management” from April 10
Just read your spectrum insight article and as (unlike in your piece) silence can also sometimes be taken to mean disinterest, then I thought I would speak up in support.
It should be considered reading for all senior users of critical communications systems who believe that they need a service similar to those provided by the mobile network operators (MNOs) to their many users.
Head of Future Networks
Head of Country (Norway)
Congratulations to David Lum on an excellent introduction to the issues, expectations and responsibilities of spectrum management.
In order to brief my clients, I have linked to it from the Spectrumwise website.
In response to “FCC Requests Information on Amateur Radio Service in Emergencies” from April 3
As radio systems get more technical and emergency response agencies struggle to keep up and maintain or recover interoperable communications, one group is ahead of the curve and available to fill gaps — the Amateur Radio Operators of America. They consistently use proven technology to back up fancy new gizmos that powerful sales organizations foist upon some unsuspecting response agencies. Without them, I think we would be more at risk from communications failure than we are now. It is important that these folks are appreciated and incorporated in emergency planning.
Ouray County, Colo.
In response to “Inside Washington” titled “FCC Adopts New TV Loudness Rules” in the March issue
I was happy to read the article about controlling the loudness of TV commercials. I would like to go one step further. Because programming is being brought in my house on my television, I think I should have total control over its use.
Because we now live in the world of digital I would like to see every commercial have a "start" and "stop" digital word that would allow me to set in my television and mute commercials if I so desire. Operation of my TV would now allow for me to set the volume for the program I am watching and mute all commercials if I desire not to listen to commercials.
I know this is a revenue stream for the broadcasters, however, that commercial is coming into private property, and I should have the right to mute the set when I so desire. It's amazing how we have digital and yet when this idea, I am sure, would be brought up to broadcasters, the response will be, "Oh, that can't be done; we have no way of doing that."
Well, I just want to go on record as saying, "Phooey on that!" Today I use the mute button all the time on my remote controller. Let's take it to the next level and allow the user to set up a "mute all commercials" in a set-up menu in the TV receiver.
Donald Backys, P.E.
RF Communications Consulting Engineer
Click here for the March 2012 Inbox.
Click here for the February 2012 Inbox.
Click here for the January 2012 Inbox.