posted 03-14-2007 10:29 PM ET (US)
I recommend you follow the manufacturer's instructions. gss036 writes:
quote:
must be too close on the Megahertz for the transducers.
SONAR devices do not operate in the Megahertz frequency range. Most SONAR transducers operate around 50-kilohertz to 200-kilohertz. If you pick up the transmissions from other boat's SONAR transducers, it is probably because they are on the same frequency or just a few kilohertz away, not Megahertz away.
In contrast to the very low frequency of the SONAR, the GPS antenna is trying to receive signals which are in the L1 frequency range of 1,575.42 MHz.
The suggestion to locate the GPS antenna at least three feet from the GPS unit itself may be related to the design of the GPS unit being insufficiently shielded. The unit may be emitting some radio frequency noise which could interfere with its own antenna. The SONAR transmitter generally excites its transducer with a sharply rising pulse of current which may contain a broad radio frequency component.
The best thing to do is to try the antenna location on a temporary basis and see how it works out.