Great Barrier Island - Port Fitzroy
Here we take a trip to Great Barrier Island (Port Fitzroy Harbour) to show the coverage improvement with our Cellutronics AMA1-5 Marine antenna.
We are on board a 38 foot Yacht and have placed the antenna temporarily on top of the cabin. Better coverage improvement would be obtained with the antenna permanently mounted on the stern or mast
We use a Samsung Galaxy SII with a direct connection on the Vodafone network. Here are our results. The first screen shot measures a receive signal strength of -97dBm (which is on the edge (poor) of coverage)
With the antenna connected the signal increases from -97dBm to -83dBm. (So a 14dB signal improvement (over 20x signal level increase)).
What do these test results mean?
- We show that even with a temporary install of the Cellutronics Marine AMA1-5 antenna a significant coverage boost in signal level is achieved. In fact the signal level increases 14dB (over 20x).
- We would also expect if the antenna was mounted permanently and in a better position such as on top of the cockpit roof, or on a fly-bridge wing the signal level improvement would be even higher.
- For those of you that are not familiar with signal levels (dBm's), the first measurement of -97 is right on the edge of signal performance. Once the level gets into the -100's calls will drop, phone won't ring all the time (missed calls), garbled speech occurs, and very slow data speeds are obtained. If you compare this to the new signal of -83dBm - this is a significant improvement in signal level. With this signal level the phone will always ring, no garbled speech and high speed data services will be achieved.
- We often get asked why our antenna is not as long as a VHF marine antenna. VHF Marine operates in the mean of 150MHz. The lowest cellular bands that operate in NZ are a mean around 900MHz. The length of the antenna is related to the frequency of the antenna. The lower the frequency the longer the antenna. As you can see 900MHz is about 6 times the frequency of 150MHz so our antenna at 400mm long at 900MHz would be equivalent to a 2400mm 150MHz antenna. We have tested longer antennas at 900MHz and the performance decreases. It doesn't matter how many times we say it - don't be fooled by other suppliers telling you to get a longer antenna. Yes they may look better on your boat being longer, and they may cost more, but you won't get the same signal improvement. The signals coming into our location in Fitzroy harbour are non line of site, meaning they are coming off reflections at high elevation angles to the antenna. Therefore you don't want a longer antenna claiming to offer higher gain. Remember, the higher gain is only achieved in the bore sight of the antenna, and a so called higher gain omni antenna will actually have lower gain when not in the bore sight. Hence we get maximum results with this size antenna.