Harold A. Dawson of Atlanta was installed recently as president of the National Association of Real Estate Brokes, the predominantly minority professional trade association whose members call themselves "realtists." Dawson succeeds John D. Thompson of Washington as head of the 3,000-member group.

Carrolltowne, a 135-acre development in Eldersburg, Carroll County, Md., is under way with the start of construction on a group of house by Washington Homes, Inc. The first section of traditional, single-family houses will be located off Ridge Road, south of Routes 26. Commercial Credit Development Corp. is the developer. The first houses will be priced in the $45,000 range.

The fourth national conference on community associations will be held Oct. 2-5 at the Capital Hilton Hotel by the Community Associations Institute. For information, call 3931000.

The Northern Virginia Board of Realtors will hold its annual awards luncheon Thursday at Vale's Steak House in Springfield, Va.

The Octagon, the historic residence on the property of the American Institute of Architects at 18th Street and new York Avenue NW, will be close Oct. 24 through Nov. 10 while a Dolley Madison exhibit is installed.

The Property Management Exposition will begin Oct. 5 at the Captial Center, where more than 130 booths will feature goods and services used by managers and operators of multi-family residential and commercial buildings. The show is sponsored by the Property Management Association and the Apartment and Office Building Association.

Written examinations for real estate brokers and sales agents in the District will be held Tuesday at the Quality Inn at 415 New Jersey Ave. NW.

Effective Oct. 1, the office of the Suburban Maryland Home Builders Association will be at 1717 Elton Rd, Silver Spring; phone 434-68000.

A one-day workshop on solar energy for beginners will be held next Saturday at the Londoun campus of the Northern Virginia Community College. For information, call 323-4551.

Two workshops for buyers or owners of old houses have been scheduled by the Preservation Resource Group, Inc., of Springfield, Va. One will be held Oct. 15 at St. James Episcopal Church in Warrenton and the other on Oct. 22 at the Columbia Historical Society in D.C. For information, call 323-1407.

Carl Golberg Real Estate, Inc., was the listing broker in the state of a five-acre tract in the Bel Pre area of Silver Spring to the National Capital Housing Foundation of B'nal B'rith. The foundation plans to build 134 apartments for elderly persons.