Offsets: where the repeater listens
Repeater offset is the difference between a repeater’s transmit and receive frequencies. You listen on its output and transmit on its input.
| Band | Common offset |
|---|---|
| 2 metres | ± 600 kHz |
| 70 centimetres | ± 5 MHz |
| GMRS | + 5.000 MHz, always |
Note that both amateur offsets can go either way: a repeater on 146.940 MHz uses a −600 kHz input at 146.340, while one on 147.150 uses +600 kHz at 147.750. The convention flips at 147.000 MHz on 2 metres, and modern radios set it automatically. The exam wants the magnitude, and that the sign varies.
Simplex means transmitting and receiving on the same frequency — no repeater involved.
Calling: three cases
You know who you want, on a repeater:
Say the station’s call sign, then identify with your call sign.
“W1ABC, this is KF1XXX.” No preamble, no “break”, no long CQ. Repeaters are shared and brevity is the courtesy.
You want anyone, on simplex:
Repeat “CQ” a few times, followed by “this is”, then your call sign, then pause to listen.
“CQ CQ CQ, this is KF1XXX, KF1XXX, listening.” CQ means “calling any station” — it is the one procedural signal everyone knows.
You want anyone, on a repeater:
Do not call CQ. The customary form is your call sign followed by the word “listening” — “KF1XXX listening.” A repeater is a small room; announcing your presence is enough.
Answering a CQ:
Transmit the other station’s call sign followed by your call sign.
“W1ABC, this is KF1XXX.” Same shape as calling. Their call first, then yours, so they know immediately the call is for them.
Band plans
What is a band plan, beyond the privileges established by the FCC?
A voluntary guideline for using different modes or activities within an amateur band.
Voluntary. A band plan is not a rule and cannot be enforced by the FCC. It is how amateurs agree, among themselves, that the bottom of 2 metres is for weak-signal work and a certain range is for FM repeaters, so that operators using incompatible modes are not sitting on each other.
Ignoring one is legal and antisocial, which is exactly the right way to think about it.
Frequencies worth memorising
146.520 MHz — the national FM simplex calling frequency on 2 metres. The single most useful number in VHF amateur radio: the frequency to try anywhere in the country when you have no other information, and the one to leave after making contact so others can use it.
Check yourself
- A repeater’s output is 146.940 MHz with a standard offset. Where does it listen?
- You want to find anyone at all on a local repeater. What do you say?
- Is a band plan enforceable?
Answers
- 146.340 MHz — a 600 kHz offset, negative on that part of the band.
- “KF1XXX listening.” Your call sign and the word “listening”. Calling CQ on a repeater marks you as new.
- No. It is a voluntary guideline. The FCC establishes privileges; amateurs agree band plans among themselves.