For improving cell reception this item by Wilson Electronics has been
recommended by Active Capitan -
http://www.amazon.com/Wilson-Electronics-Sleek-Kit-Packaging/dp/B00I9I67Z2
For a ground plane they suggested a 12" pizza pan and used the antenna's
magnetic mount to attach it. Note - for this to work the phone must stay
in the cradle so you would have to user it in speaker mode. It will also
work to increase Internet performance if using the phone as a WIFI hotspot.

It appears Wilson is selling a similar newer device -
http://www.amazon.com/weBoost-Drive-4G-S-Phone-Booster/dp/B00RHMFPCW/ref=dp_ob_title_wld

Also, if you don't want to leave the phone in the cradle they have items
like this but the price is about triple the Sleek 4G -
http://www.amazon.com/weBoost-Drive-4G-M-Phone-Booster/dp/B00RHMFPEU/ref=sr_1_1?s=wireless&ie=UTF8&qid=1428803776&sr=1-1&keywords=weBoost+Drive+4G-M+Cell+Phone+Signal+Booster+Kit

Here is the Active Capitan article -
https://activecaptain.com/newsletters/2014-11-12.php

And here is Wilson's web site -
http://www.wilsonamplifiers.com/amplifiers-4g/?sort=bestselling

I haven't personally tried any of these but think cradle weBoost 4G is
in the near future.

Ray Macke

Dennis, we use a Wilson 4G +50 cellular amp on our boat. The CRUCIAL factor
however is the proper antenna. There MUST be a ground plane design on the
antenna (unless you have a sailboat with the antenna atop the mast which is
not practical because of coax losses). Unless there is considerable
separation between the internal antenna and the outside antenna, there is a
strong chance of feedback oscillation which can destroy the amplifier or at
least disable it. We have a Shakespeare 2 foot cell antenna on a two foot
mast atop our hardtop. I do not have the model number before me, but the
unit has six ground plane spikes at the base of he antenna which forms a
virtual ground plane which keeps the amplified external signal from reaching
down into the cabin of the boat where the internal antenna is.

Most of the Wilson units are designed for cars with a magnetic mounted
antenna on the roof. However, the roof of the car then serves as the ground
plane and isolates the external signal from the internal antenna.

I then use my iphone in the cabin as a wifi hot spot and it works well, up
to 18 miles offshore. However, without the ground plane design antenna, the
internal amplifier will go into feedback oscillation and quite possibly burn
itself out.

Another caveat, there must be a line of sight to a distant cell tower for
the system to work. We boat primarily in the Apostle Islands on Lake
Superior and if an island is between us and a cell tower, there is no signal
to be amplified.

David Sorenson
Duluth, MN