TO: ALL WOOD COUNTY ARES MEMBERS (OFFICIAL)
ALL ARES AND NON-ARES AMATEURS ANYWHERE (INFORMATION)
FROM: KEN HARRIS WA8LLM ARRL DISTRICT 3
EMERGENCY COORDINATOR WOOD COUNTY EMERGENCY COMMUNICATIONS INC.
WOOD COUNTY ARES BULLETIN NR 21.02 DATE: January 10, 2021
SUBJECT: WHAT IS SIMPLEX?
Some people might be a little confused about the word SIMPLEX. In radio use, the word simplex means that only one frequency is involved. When operating on simplex, it means that you are transmitting and receiving on the same frequency.
When operating DUPLEX, your transmitter is transmitting on one frequency and your receiver is receiving on another. When you are operating on a repeater, you transmit on one frequency and you receive on another. The difference between the transmit frequency and receive frequency is called OFFSET. Depending on what band you are operating, the offset frequency can be 600 KHz above or below your transmit frequency. On some bands the offset frequency can also be 1 MHz, 5 MHz, 12 MHz or 25 MHz, and maybe others.
So when some one tells you to go simplex, and they tell you a frequency, you will know that you are transmitting and receiving on the same frequency, and you don't need to worry about an offset.
Ken Harris WA8LLM
Wood County WV