The Sulphurites take on the 2008 FA Cup winners once again, just over two years on from the clubs’ 2019 meeting at the first-round stage of the competition.
Pompey regularly attract home crowds in excess of 14,000, while by comparison, the gate of 8,199 at Swindon last weekend was the biggest Town have ever competed in front of.
“It will be hostile at Portsmouth, without a doubt,” Weaver said.
“When we drew them in the FA Cup two years ago, Paul Thirlwell and I travelled down to watch them play Southend and the atmosphere was something else. They’ve got a really partisan crowd and that bell. You certainly know that their supporters are there.
“But, we want our lads to embrace it. We deserve these moments and we want to give a good account of ourselves, prove we belong in stadiums like Fratton Park – and to enjoy it.
“The players need to settle down and try and carry out the game-plan. They did that fantastically well at Swindon at the weekend. They handled their crowd, who turned up thinking they were going to roll us over.
“Once they realised after the first 10 minutes that it wasn’t going to happen they became a bit frustrated and if you go about it the right way, and stay composed, you can turn a big home crowd against their own team.”
Town, currently 7th in League Two, set up their meeting with Portsmouth by beating National League Wrexham 2-1 last month, while League One Pompey edged out Harrow Borough of the Southern Premier League.