[VAL] Re short range broadcasting

["David Josephson" <david@xxxxxxxxxxxxx>]

Indeed there are other broadcast engineers on this list, and a number 
who have Airstreams -- for a moment I thought that I was reading a 
different list!

I am here to add to the advice you've already read from Gerald Johnson 
and others. There is no legal, practical way to cover a rally area with 
a temporary FM broadcast transmitter. The legal, unlicensed transmitters 
cover about 100 feet at most. There have been FCC inquiries and 
petitions over many years to establish an "event radio" service as 
suggested here (and such a thing exists in Denmark, the UK and Canada) 
but it hasn't happened here. There are a number of possible options 
however, and this is from the perspective of someone who passed the FCC 
First Class test at age 16 -- rather more than 30 years ago -- and has 
been chief engineer and consultant for quite a few radio stations over 
the years. I should say too that I've been retained several times by 
groups trying to do just this sort of thing -- and have tried a number 
of approaches to get an official OK to do something along these lines. 
No luck yet.

The suggestions of "test" and "experimental" licenses have been brought 
before the FCC many times. Each time the petition is denied, because the 
justification for test, experimental or developmental operation is not 
present.

The reality of dealing with the FCC today is that it's grossly 
understaffed, and anything that takes licensing had better be quite 
lucrative (like the spectrum auctions that helped bankrupt early 
wireless internet efforts) or be nearly automatic, like GMRS and amateur 
licensing.

A number of music festivals and racing events operate totally illegal 
radio stations for short periods, under the concept that the FCC is 
unlikely to enforce the rules for a violation that causes no actual 
interference. As one FCC enforcement engineer told me many years ago, 
"we know who they are, they aren't bothering anybody, and they'll be 
gone on Monday." In some cases however (notably at racing events in 
cities) these stations

In truly extraordinary circumstances (the Olympics in Los Angeles and 
some Superbowls), the FCC has granted a one-time Special Temporary 
Authority for existing licensed broadcasters to operate low-power 
stations within a venue like a stadium. In each case this is built on 
the consulting engineering of the local chapter of the Society of 
Broadcast Engineers which does frequency coordination for all the 
wireless microphones, video and two-way at such events too. And the 
licensees need to be existing licensed broadcasters or networks.

If you are unwilling to sail under the pirate flag, however, there are 
still some alternatives.

One is doing a deal with a local station, most of whom are on very tight 
budgets and would be happy to work something out for a few days.

Another is to build a network of legal short-range stations linked 
together by wire. The rules permit much greater range on the AM band 
than on FM. You can operate transmitters intended for "carrier current" 
operation, which couples a small amount of radio frequency energy into 
the power lines. There is a company specializing in this equipment 
called LPB (www.lpbinc.com). You can also string "leaky" cable around a 
venue, and any radio within a few hundred feet of the cable can pick it 
up. This does require some engineering to set up and qualify, but it can 
be done.

Many local governments are licensed for "Travelers Information Stations" 
that can cover several miles on AM. It's up to them what programming 
they put on, within limits. If you can make a deal with the city where 
your rally is, TIS might be an option.

Yet another possibility is to stream audio over a local Internet 
connection using WiFi. It would require that everyone tune in with a 
laptop computer -- practical over a range of at least a mile, legally.

Finally there is another alternative that I have been working on for a 
couple of years, and if anyone wants to try this in any of the west 
coast states, my company holds blanket licenses that would permit it. 
(For the engineers on the list, these are Part 22 allocations licensed 
on a geographically exclusive basis, up to 600 watts ERP at any number 
of fixed locations without further FCC filing). There are former paging 
frequencies that the FCC has licensed for a wide range of common-carrier 
activities. Our test transmitters (one of which rides in my 1971 
Tradewind) cover more than 50 miles on 35 or 43 MHz. The only catch is 
that you need a special radio to pick up these transmissions. Most 
police scanners will work, and we can provide fixed-tuned receivers for 
about $10 apiece if the quantity is large enough. It's been a hard sell 
as people really would prefer to tune in to an event radio on their 
existing AM/FM receiver. We are interested only in providing the service 
as a common carrier. There is interest in doing this sort of thing at 
conventions, rallies and all sorts of other events. We have access to 
these channels through other licensees in much of the rest of the US as 
well. If there is a group interested in pursuing the business and 
financial aspects of this, the legal and technical part is already done 
... please contact me off list and we can discuss the details.

--
David Josephson