The Maryland Senate today gave final approval to its own version of Gov. Harry Hughes' proposed $105 million capital construction budget, including money to build a new 720-bed prison at Hagerstown, the 12th major penal institution in Maryland.

With Hagerstown's favorite-son senator, Victor Cushwa (D-Washington County), rising as the lone voice of opposition, the Senate approved the budget by a vote of 38 to 1. Borrowing a phrase from Hughes' January State of the State speech, Cushwa declared that in faraway Washington County, "I want you to know its cold out there."

A House and Senate conference committee still must meet to settle key differences in the capital budget, including disagreement over how much money to spend studying the need for a 13th prison and where that prison should be located.

The House version of the capital budget includes $250,000 for a site-selection study for a new prison, with no location stated. The Senate has asked for $800,000 for that same site search, but prohibits the new prison from being built near any of the existing facilities at Hagerstown, Jessup or Baltimore City.

The senators also will ask for the three temporary huts used for prisoners at Hagerstown to be dismantled once the new 720-bed prison is built there in 1985. There are also disagreement on whether prison workers must be hired from unemployment-racked Washington County, or from any place in western Maryland.

The deals surrounding Gov. Hughes' attempt to get a one-year extension on a $22 million bond issue for Baltimore's Memorial Stadium continued today as another senator was persuaded to back off from a filibuster.

Sen. Howard A. Denis (R-Montgomery) agreed to end his 80-minute filibuster after receiving assurances that a bill to create community group homes for the mentally retarded would be moved out of committee Friday. That promise came after some frantic searching for money to pay for the homes by members of the Budget and Tax Committee, which had killed the funding mechanism for the group homes bill on Wednesday.

If the group homes bill, complete with financial backing, passes the Senate Friday, Denis said he would forgo another filibuster when the stadium bill comes up for final Senate passage. The stadium bill still must pass the House of Delegates before the session ends at midnight Monday.

Denis arrived on the Senate floor today equipped with aspirin and throat lozenges. He had been one of seven senators threatening to filibuster the extension on the bond issue, an issue that will otherwise die June 30. The other legislators agreed not to filibuster in return for the killing of four antibusiness bills.

One of the four bills was a windfall profits tax. Hughes had agreed to use the money from that tax to create the group homes.

"We're expected to vote for a bill so that millionaires can have luxury boxes at a football stadium when the truly needy are being ignored?" Denis asked. He also charged that Colts owner Robert Irsay "will never sign a long-term lease."

Irsay's refusal to sign a long-term lease is the reason that the stadium-improvement bonds, authorized by the legislature two years ago, have never been sold.

While Denis spoke, members of the Budget and Tax Committee were completing work on a compromise that would use several other bills to pay for the group homes. Each of the senators had been flooded by angry phone calls from members of the Association for Retarded Citizens of Maryland after voting 7 to 6 Wednesday to kill the windfall profits tax bill.

Hughes is scheduled to meet Friday with Del. Lorraine Sheehan (D-Prince George's), sponsor of the group homes bill, regarding financial commitments for the measure. "If they are firm, I won't filibuster," Denis said. "If not, I'm prepared to start again."

A referendum to put tiny Takoma Park in one county appeared dead today after Prince George's delegates rejected a compromise with neighboring Montgomery County.

The two counties have been feuding over which county would give up its share of the city. Takoma Park is about two-thirds in Montgomery and one-third in Prince George's.

Montgomery delegates last month passed a bill calling for a referendum asking the Prince George's residents to join Montgomery. The Prince George's delegates amended the bill to allow those in Montgomery County to vote to become Prince Georgians.

Last Saturday, in a conference committee held over beers at Harry Browne's restaurant, the two sides reached a compromise: Residents of each section of the city would be allowed to decide if they wanted to join the other.

Montgomery acccepted the conferees' suggestion, but Prince George's delegates rejected it by an unofficial tally of 14 to 5. "I guess they didn't want to give the people a chance to decide the issue for themselves," said Del. Stuart Bainum (D-Montgomery), author of the defeated bill.

A bill exempting localities from federal antitrust laws when they award exclusive cable television franchises was enacted today when it passed the Senate on a 40-to-1 vote. The bill, already approved by the House of Delegates, now goes to Gov. Hughes for signing. Hughes was a principal backer of the bill.

The legislation, approved by a 40-to-1 vote in the Senate, was needed because of a Jan. 13 U.S. Supreme Court decision declaring that localities are not immune from antitrust lawsuits when awarding cable or other exclusive franchises unless state legislatures vote to exempt them. In Montgomery County, which is scheduled to award its cable franchise this summer, the county attorney had recommended delaying the entire process unless this exemption bill passed this year.

A bill designed to force welfare recipients to work for their monthly checks was killed Wednesday by the Senate Finance Committee. By a 4-to-3 vote, the committee rejected a bill authorizing the state's Human Resources Department to establish "workfare" demonstration programs.

The measure was opposed strongly by social service advocates and by labor lobbyists, who argued that it would be ill advised to force welfare recipients to work at a time when Maryland is suffering record-high unemployment.