TO: ALL WOOD COUNTY EMERGENCY COMMUNICATIONS AMATEURS
ALL NON-WOOD COUNTY EMERGENCY COMMUNICATIONS AMATEURS
FROM: KEN HARRIS WA8LLM
WOOD COUNTY EMERGENCY COMMUNICATIONS INCORPORATED
WOOD COUNTY BULLETIN NR 13.49 DATE: December 8, 2013
SUBJECT: STEP IT OFF
When erecting temporary antennas for communication activities such as Parades, Exercises, Field Day, or actual Disasters, it's best that you don't use any more coax, or transmission line then is necessary. The best way to keep from using more transmission line then is needed, is it step it off.
The average foot step is about three feet, so it's easy to estimate what length of coax is needed. Most of the time it's not critical to have the exact distance, so stepping it off is good enough.
There are times when old antenna systems are being taken out of service, and you might be able to acquire the old coax. Just because coax is old doesn't always mean it's not any good. Strip a short piece of the coax and look at the copper shield. If it's still shiny, there's a very good chance the coax will be good for many more years.
If the pieces of coaxes are 20 or more feet in length, that's okay. You may want to cut off the old connectors and replace them with new ones. Before installing new connectors place a piece of red heat shrink tubing over each end the coax, but don't shrink it yet. After installing new connectors and testing the coax, then shrink the heat shrink near the connector, measure the coax length, and mark the length on the heat shrink.
On one end of the coax place, and tighten, a double female, or barrel connector, and cover the connection with heat shrink, so they can't be taken apart. Now you have coax extension cables of various lengths, and you don't have to find a double female or barrel connector to splice them together.
When you get ready to install a temporary antenna, step off how many feet of coax you need, and use your various lengths. Example: If you need about 75 feet, and you have a 50 foot, and a 30 foot piece of coax, you're in business. It's nice to keep several coax extensions on hand for different temporary installations.
Ken Harris WA8LLM
WCEC
Wood County WV