Cellular / VHF Antenna Separation

Product Discussion
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In my continuing dilemma for antenna placement in a sailboat marine application, I am giving serious thought to mounting a pair of cellular antennas at the mast head, and placing a the Peplink device as close to the mast head as possible. Obviously POE is ideal in this scenario, and this is supported by the BR1 Mini. I am assuming that the Mini has the same performance and the BR1 MKII and other units.

This brings up the issue of separate between the cellular antennas and the VHF antenna on the boat. From the diagrams I included in my other thread, Cellular / WiFi Antenna Separation, there is recommended horizontal/vertical separation between VHF and cellular antennas of 2’. I have illustrated that in the diagram below.

So this would be the ideal situation, to minimise interference even when the VHF radio is transmitting. However, given the the VHF radio (25W) only transmits very rarely, can these distances be reduced so that the only concern is ensuring the metal aspects of the antenna don’t interfere with each other? There is an AIS transponder transmitting on the antenna, which is a small burst at 2W every 10s.

Thanks,

Allan.

ant2
ant2539Ă—734 12.7 KB

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Yes. I think so. A Class B AIS TX will definitely cause no issues and I think it unlikely your 25W TX will either. And, you are not going to experience a harmonic from cel to marine freqs. Further (and importantly) you have the rad center of the marine antenna well above the rad centers of the cel antennas. (Nice diagram, BTW – really helps! :+1:)

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@Rick-DC et al,

Specifically, could the distances be reduced to something like this? 90cm was the Poynting ideal minimum recommended separation for their antennas.

Thanks,

Allan.

ant3
ant3911Ă—946 44.5 KB

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Hi. While I’ll leave a definitive answer to others who have marine experience, my quick answer is “it’s OK.” Had you not raised the 2-way/AIS antenna the way you have I’d be slightly uncomfortable with this because its mast is right about 1/4-lamda at those freqs from the cel antennas. But my gut is the proposed scheme is fine. A few inches more separation wouldn’t hurt, however.

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