USCG Advisory re: TV antennas affecting GPS
- Thread starter Doryman
- Start date
localboy":28y1m7nn said:
Mark, I'm thinking that I'll take advantage of this situation and install a "dummy" Marine Television Antenna and then when any boat sees that, they'll stay 2000 feet away from my vessel and I'll have the seas to myself......no more someone trying to play bumper boats with me.....
In the last year or so I have had two instances where my boats position on my GPS "moved erratically across large expanses of land." The first time that it happened, I thought that my GPS was going into a series of last gasp spasms before dying. It was very strange. I wish that I could recall if any other boats were in the area or not. It lasted for less than a minute, but I was zig zagging across large expanses of beach and forest. :shock:
Robbi
Robbi
The key word here is "active" TV antenna. This problem has been reconginzed for quite some time--and there are other specific areas of interference. The question I have is since this warning was posted in 2002, are these specific antennas even manufactuered currently--and has the problem been fixed?
The times we have lost GPS usually was near an active Military ship--talk about "Active Antennas!....
The times we have lost GPS usually was near an active Military ship--talk about "Active Antennas!....
Bob,
If I understand the FCC rules, a device such as these active antennas that causes interference to a service such as GPS that operates in an exclusive protected frequency space, would have to be removed from the market. There are permissible limits for interference, but the distances are meaured in inches or at most a foot or two. The best example of this is police radar detectors. Some of the early models generated frequencies in the 950-1450 MHz area that interfered with some cellular services as well as L-band satellite modems. The FCC forced the manufacturers to withdraw them from the market. It doesn't mean they all go away, it just means that they can no longer be sold.
My Lowrance GPS has always been sensitive to marine radar. They have since improved the shielding in the antenna electronics assembly, but on my current model, if I get too close to one of the Alaska ferries with its radar operating, the GPS goes off line.
If I understand the FCC rules, a device such as these active antennas that causes interference to a service such as GPS that operates in an exclusive protected frequency space, would have to be removed from the market. There are permissible limits for interference, but the distances are meaured in inches or at most a foot or two. The best example of this is police radar detectors. Some of the early models generated frequencies in the 950-1450 MHz area that interfered with some cellular services as well as L-band satellite modems. The FCC forced the manufacturers to withdraw them from the market. It doesn't mean they all go away, it just means that they can no longer be sold.
My Lowrance GPS has always been sensitive to marine radar. They have since improved the shielding in the antenna electronics assembly, but on my current model, if I get too close to one of the Alaska ferries with its radar operating, the GPS goes off line.