Masthead mobile internet/phone antennas

[LoudMusic]

Originally Posted by Jerry Woodward

Since cell towers are well, towers, and then generally mounted on hills at the highest point, I wonder whether you gain anything by mounting a cellular antenna at the top of the mast. I think the angle from the cell tower down to the boat would be pretty much the same whether to the top of the mast or to the stern rail. If you are far enough away to make the earths curvature come into play, I don't think you would be receiving a cell signal anyway. I have mine mounted on the stern rail and it has been working great off the west coast of Florida. Of course, I have never directly compared stern vs mast mount.

I am no expert and I would love to hear an expert discuss this issue.


I think the more important issue is that you get a MIMO omnidirectional antenna (two antennas inside a radome) and run two coax cables (they are pretty thin). Here is my antenna, very well made and works well.


https://www.semiconductorstore.com/c...dproduct=71870

Raising the antenna up the mast gets it over nearby obstructions such as landscape, buildings, and other vessels. Sometimes it only takes a few meters to make a big improvement. It certainly isn't a magic fix for long range cellular service, but it can help in the right conditions and personally I think it's worth the effort.

[BobFord]

I would recommend the ERICSSON router . With the antenna at mast head , I have surprising reception , phone and internet, in very remote places. I estimate a range of 35 to 50 n.m from transmitter. Antenna is 30 m above w/l and uses 40 m of cable, was installed at mast build ,6 yr ago.

[Jerry Woodward]

Originally Posted by LoudMusic

Raising the antenna up the mast gets it over nearby obstructions such as landscape, buildings, and other vessels. Sometimes it only takes a few meters to make a big improvement. It certainly isn't a magic fix for long range cellular service, but it can help in the right conditions and personally I think it's worth the effort.

Yes, I agree that would be important for a source at low level, like a marina WIFI. But aren't most cell towers located above these obstructions? Thats why I wonder whether these considerations are really as important for cellular signals.

[Snowpetrel]

Lots of very interesting stuff, thanks for all the input. I hadn't thought about the maximum range of the base systems.

What I do know is one of my favorite spots has pretty poor reception, it works just if I am outside, so maybe I really don't need to get any more fancy than a rail mount antenna.

Bob that ericsson router and antenna sounds perfect, if it can cope with 30 meters it should be fine for my 16 meter mast. It would be interesting to get some more details.

I remember my father had a masthead antenna on the fishing vessel he ran. I used to talk to him 60-70 miles offshore back in the 90's. Also heard a few Syd-hobart racing boats fitting something at the mast to give better reception offshore for weather files. From what I heard they were almost getting coverage over the whole route.

Ive also walked up plenty of hills to get reception. Used to be from deal Island in the middle of Bass strait you could get a signal from half way up the track, but not in the anchorage. Also coming back from antarctica on the icebreaker we all crowd up on the monkey island near Pedra Branca island south of tassie, and start getting signal, but you lose it lower down on the ship. So height definately seems to help.

But then for me cost is a big factor, I really can't justify spending lots of money on something that's not core to getting the boat back sailing again. If a simple, cheap antenna will work that would be fantastic. If it takes an expensive set of boosters and routers to make something effective these days I will leave it for now.

[Snowpetrel]

Originally Posted by Jerry Woodward

Yes, I agree that would be important for a source at low level, like a marina WIFI. But aren't most cell towers located above these obstructions? Thats why I wonder whether these considerations are really as important for cellular signals.

Down here in Tassie the terrain is quite hilly, so its pretty easy to lose line of sight in an anchorage. The coverage is much better than it used to be but no where near perfect once you get away from major cities.

[swampbush]

I use a black hawk antenna at the top of the mast. Cable losses can be huge if you don't use quality cable. I used lmr400, which is 10mm in diameter, and comes in a flexible version. Cable loss is lower at the lower frequencies that you will be using further from the coast. Optus and Telstra have a large amount of 700mhz 4G coverage. The antenna means I get coverage at more remote spots like Middle Percy and Island head creek, and Lady Musgrave. My portable antennas didn't get much if any signal at water level. Telstra coverage at more than 90km is easily achievable, particulary if the tower is elevated.

Originally Posted by Snowpetrel

Anybody used a masthead mobile phone antenna of any sort. What are the pitfalls?

I can see signal strength losses being a big one on a tall mast. Most antennas only seem to have 5 meters of cable. I guess I would plug it into a wifi router at the base of the mast. Not after super speeds, Just seems like a good way to reduce the black holes in enclosed bays and give extra range offshore. There are some very expensive units with amplifiers and the like at $1000 or so. and much cheaper $30 antennas.

Seems like a small antenna would beat the hastle of having to hoist the router or phone up the mast in a plastic bag, or climb up to the spreaders just to get a few bars of signal.

I am based in Aus and currently using the telstra network.

[Snowpetrel]

Thanks Swampbush. Sounds like a good and reasonably cost effective unit. Any issues with your masthead VHf antenna?

[swampbush]

No issue with the vhf, try to keep them a bit apart if possible I guess but they don't seem to interfere with each other.

Originally Posted by Snowpetrel

Thanks Swampbush. Sounds like a good and reasonably cost effective unit. Any issues with your masthead VHf antenna?

[Wotname]

Originally Posted by swampbush

No issue with the vhf, try to keep them a bit apart if possible I guess but they don't seem to interfere with each other.

Especially vertically!

[Snowpetrel]

Do you use the same sort of Coax wire for mobile antenna as the VHF?

Maybe a good compromise would be to run one excellant quality coax up the mast. This could be used for vhf or mobile services by swapping over the antenna. Most of the time the mobile antenna could be plugged in, but for racing where a masthead VHF is needed I can swap them over. This save the weight and cost of two coax cables up the mast. Id make sure there is space for another coax if I find it useful to have both up the mast.

[Wotname]

Originally Posted by Snowpetrel

Do you use the same sort of Coax wire for mobile antenna as the VHF?

Maybe a good compromise would be to run one excellant quality coax up the mast. This could be used for vhf or mobile services by swapping over the antenna. Most of the time the mobile antenna could be plugged in, but for racing where a masthead VHF is needed I can swap them over. This save the weight and cost of two coax cables up the mast. Id make sure there is space for another coax if I find it useful to have both up the mast.

In essence, yes, the coax is the same for mobile as the VHF. Connectors may be different but that is a very easy problem to solve with adaptors etc.

[hzcruiser]

Originally Posted by Snowpetrel

Do you use the same sort of Coax wire for mobile antenna as the VHF?

Maybe a good compromise would be to run one excellant quality coax up the mast. This could be used for vhf or mobile services by swapping over the antenna. Most of the time the mobile antenna could be plugged in, but for racing where a masthead VHF is needed I can swap them over. This save the weight and cost of two coax cables up the mast. Id make sure there is space for another coax if I find it useful to have both up the mast.

You want to go up the mast to switch from one to the other?



One coax (e.g. LMR400) would work if you had a bandpass filter on the mast that's connected to the VHF and a high-pass for the GSM/4G. Not sure if you can buy that off the shelve though. Maybe this one:


https://www.powertec.com.au/blackhaw...itter-698-2700



The same filter at the bottom and you could use both radios/phone simultaneously.

[Snowpetrel]

^^ a very clever idea. No way I have the electrical smarts to come up with that, but it seems like something along this line would be ideal. Maybe a clever RF engineer could even work out a way to make the one antenna do VHf and mobile, much like they use the same antenna for vhf, AM and FM radio? https://www.roadtechmarine.com.au/vh...itter/p/MDE126

[Wotname]

Almost anything is possible RF wise if you throw enough money at it .
However IMO, the above concepts (posts 27 & 8) are not practicable; too expensive, too large, too complex, anything but KISS.

IMO, the most complex solution should be nothing more than two coaxs and two antennas. Work backwards from there is you need something simpler or cheaper.

[Snowpetrel]

^^Cheap and simple appeals to me as well Wottie. Thanks for the touch of realism.