Expedition Expedition Navigation Software

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8/08/2019 4:48 am  #1


GSM / UMTS / LTE antenna

Hello,
I wonder if anyone in this forum made good experience with installing a GSM / UMTS / LTE antenna for -basically unlimited- data download during offshore races that stay at least part of the time relatively close to the coast (like Fastnet, Middle Sea Race, Carribean 600 etc.).
Any models to recommend?

 

8/09/2019 5:15 pm  #2


Re: GSM / UMTS / LTE antenna

Nav
I think this might be a much more complicated question than you have asked.  For example, we dramatically improved 4G reception by moving the modem/router within 1 m of the 4G aerial.  So toplogy has a profound impact; signal loss due to co-ax length is one key factor.  Also the physical geography of where you are - the higher that mobile phone tower, the longer the range you can expect offshore.  I suspect choice of carrier might also make a difference (tower height and density etc).
And so on .....

 

8/09/2019 9:59 pm  #3


Re: GSM / UMTS / LTE antenna

The cheapest and easiest way to get extended 4G range is to use a spare halyard to hoist a mobile phone with a wifi hotspot enabled into the top of the mast.  I haved used this once and it worked perfectly.

 

8/10/2019 7:53 am  #4


Re: GSM / UMTS / LTE antenna

I've a MiFi type router in the nav station, with one of it's two external LTE antenna connections connected via very heavy coax (RG-12?) to a masthead antenna. It works quite well: the router/LTE transceiver is well protected and accessible down below, but reception isn't as good as I'd hope - more than 5 nm off reception is patchy. My guess is coax length and losses are the issue. I can't recommend the hardware strongly enough, it's reliable and reasonably sophisticated whilst quite easy to set up. I use a Teltonika RUT550, which has now been superseded by the 9xx series. It also is possible to configure it so that it uses the mobile data as an automatic back up to some other WAN connection, such as marina WiFi. I guess I'll replace it with a 5G device in the next year or two, and then the debate will be over the relative merits of a similar arrangement vs a closely coupled/integrated antenna transceiver at the masthead. 

 

8/10/2019 1:21 pm  #5


Re: GSM / UMTS / LTE antenna

Tom, the coax cable length will kill it every time.  With a stern mounted aerial and adjacent modem, I get reception 18-20 miles offshore.  Call a manufacturer and hear what they says about maximum coax cable length.

 

8/11/2019 12:20 pm  #6


Re: GSM / UMTS / LTE antenna

Duncan,

Thanks, that confirms my guess. The question then becomes if it's worth putting the whole lot up the rig or just have it at deck level. If you're getting up to 20nm, then it sounds as though antenna height might not be that critical - though that rather flies against ZeeZee's experience from housing a phone up the rig - unless he was even further off. Though I guess the relatively poorer antenna gain of a phone's antenna would be a factor too. As you observed at the outset there are lots of variables in here.

Tom

 

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