The NAV6 or NAV6plus should give good Navtex reception within the published service area. Over a sea path, this can extend to as much as 200 – 300 nautical miles from the transmitting station during daylight hours. If the direct signal path crosses land to any significant extent however, attenuation may occur which could reduce the reception range to as little as 50 miles.
Navtex range increases significantly at night and can extend to as much as 1000 miles – sometimes more.
Background electrical noise in a marina, the presence of high cliffs and the masts of surrounding vessels can all contribute to poorer reception when in harbour, rather than at sea.
If you want to increase the sensitivity of your system and hence the range of reception, there are two things that can be done to optimise the installation. Either one of them can lead to a big improvement.
- Connect the screen of the interconnecting cable from the connecting block direct to a good electrical ground. This can either be a specially installed ground plate, or the keel bolts on a non-encapsulated keel.
- On a yacht, have the back stay insulated and connect it directly to the top of the NAV6 sensor, in place of the whip antenna.
For the ultimate in results, try both.
We would emphasise that in normal circumstances, none of these measures should be necessary. However, if you wish to frequently receive Navtex at extreme range, either may be worth trying.