Poate left Gosport Borough by mutual consent earlier in the week after nine years with the National League South club.
Moneys boss Carter wasted little time in capturing the experienced defender.
Poate was wanted by several clubs but he has chosen the switch to Dover Road.
He views the 33 year old as another important piece of the jigsaw in their bid for the league title.
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Carter said: ‘We managed to beat off a number of other clubs to capture his signature.
‘He is vastly experienced with more than 600 Conference South games under his belt.
‘Though we already have a pretty good defensive record he can give us something extra.
‘At this stage of the season it is great to be able to freshen things up a little.
‘He is a great defender and knows what it takes to be a winner.
‘At Gosport he won a number of promotions and also played at Wembley in the FA Trophy final.
‘He is happy to drop down three levels and play his football locally for the rest of this season.’
Poate is Carter’s third big signing recently having already landed Dan Wooden, from Gosport, and goalkeeper Steve Mowthorpe, from AFC Totton.
With Moneyfields 10 points clear at the top the manager is keen to maintain that advantage.
The Dover Road club are targeting a move up to the Southern League and know the only way of making sure of that is to win the league.
Carter believes the big signings are a statement of the club’s ambitions.
‘The Wessex premier is not an easy league to get out of,’ said Carter.
‘Usually there is only one place up for grabs.
‘We have got ourselves in the driving seat and want to make sure we stay there.
‘With the new arrivals we have now got a good spine running through the team.’
Eighth placed Alresford are also on a good run.
They will be tricky customers on their relatively small pitch.
Carter is without Lewis Fennemore and Alex Sheppard, who are both suspended.
Their captain and striker Steve Hutchings, however, is back and available.
Carter is looking for a big improvement on their last outing when his side were held to a 2-2 draw by lowly Fareham Town.
‘They were two points dropped against Fareham but fortunately the other results went for us on the day,’ said Carter.
‘That won’t always happen so I don’t want us to be dropping any more in this game.
‘We have to make sure we get ourselves up for all the games and approach them the right way.’
Moneyfields: Mowthorpe, Bailey, Spurway, Austin, Poate, Hayes, Da Costa, Giddins, Woodward, Martin, Wooden, Raine, Paxton, Hutchings, Guthrie, Tigwell, Howes