| Business | Phone |
| American Microwave 4507 Metropolitan Ct, Frederick 21704 | (301) 874-3736 |
| Burlington Industries Frederick 21702 | (301) 473-9965 |
| Goodman Manufacturing 4959 New Design Rd, Frederick 21703 | (301) 631-2452 |
| Herley Industries 7435 New Technology Way, Frederick 21703 | (301) 662-8000 |
| Planar Filter Co 7311 Grove Rd # G, Frederick 21704 | (301) 662-0733 |