Archive for September, 2008

NTIA/IAFC report reveals serious fire service concerns with digital-radio systems

Posted in Ham Radio, Law Enforcement, Radio Communications with tags , , , , , on September 10, 2008 by WA4ZKO

Fringe range performance and spectrum efficiency are often the only advantages to going digital.

A recent NTIA study concerning issues with digital 2-way radio usage in the fire service has revealed some very serious issues.  The study itself can be found here.  MRT’s article on it can be found here.  Some interesting comments on this topic can be found here, take ’em for what they’re worth.

For those that know me, know I’ve preached on this topic for about 2 years now. Just because something is “digital” doesn’t mean it’s automatically better. For sure, digital-radio has it’s place in communications, but it’s not without it’s own pros and cons. You have to weigh these factors in first and not just jump into the “latest and greatest” mindset that is so pervasive in our society today. Often the “latest” is just that and not the “greatest.” The often over-hyped marketing of this technology does not help folks/agencies make wise choices either.

I’ve personally heard vocoder performance failures outside of the fire service. A local city PD in Connecticut had a post vehicle pursuit incident where background noise created a communications mess. As the pursuit ended, they had several officers jumping out of cruisers quickly to contain the suspects. Several units still had their sirens running and you can probably guess what resulted on their UHF digital system.

Yes, the vocoders have come a long ways in the last few years. I’m sure they will improve things even further, but folks there are certain fundamental laws of physics that apply to audio and THEY ARE WHAT THEY ARE.  Without widening the bandwidth, there is only so much sampling and DSP work you can do and keep things contained in a few KHz of channel width. It will be interesting to see how the technology plays out, but for now it is what it is.

Yes user education/training is also needed. From my public safety background I’ve been on both ends of these communication circuits (dispatch & in the field). One of my big radio communication pet peeves is the trend toward “plain language” public safety radio communication techniques, the errors this introduces, and the negative radio discipline that often creeps in. If I had a dollar for every “repeat” or out right misunderstandings caused by poor radio discipline I’ve heard, I’d be retiring at age 40, grin. That’s true even considering I don’t listen to local public safety radio that much anymore as it’s too annoying to monitor daily.

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Solar history made – 1st spotless sun in about 100 years.

Posted in Ham Radio, Radio Communications on September 1, 2008 by WA4ZKO

Lot of history made in August 2008. This one will probably fly under the radar of most folks. For the first time in about 100 years, we have an entire month in which the sun was spotless. Safe to say we’re at the bottom of cycle 23 now, grin. Full article here.

Some interesting parts in the article, then some are questionable. This comment struck my eye….

“The event is significant as many climatologists now believe solar magnetic activity – which determines the number of sunspots — is an influencing factor for climate on earth.

Well? The sun and it’s cycles might be responsible for weather changes on earth?? Ah, you think? DUH!