Question E2C12:
What indicates the delay between a control operator action and the corresponding change in the transmitted signal?  

Choices:  
A: Jitter  
B: Hang time  
C: Latency  
D: Anti-VOX    

Correct Answer is  C: Latency  

Correct answer: C — Latency

1) Why “Latency” is correct
- Latency is the time delay between an input action by the operator (PTT, keying, changing frequency, etc.) and the resulting change at the transmitter output.
- It is literally the “control-to-RF” delay, often measured in milliseconds.

2) Why the other choices are incorrect
- Jitter: Variation in latency over time. It describes how the delay fluctuates, not the delay itself.
- Hang time: A repeater’s intentional transmit “hold-on” time after input drops (to avoid choppy audio). It’s not the control-to-signal response delay to an operator action.
- Anti-VOX: A feature that prevents the VOX from being triggered by the station’s own speaker audio. Not a timing/delay metric.

3) Useful formulas and rules of thumb
- One-way propagation delay for distance $d$ (in meters):
  $$t = \frac{d}{c}, \quad c \approx 3 \times 10^8\ \text{m/s}$$
  - Rule of thumb: $1\ \text{km} \approx 3.3\ \mu\text{s}$; $1\ \text{mile} \approx 5.4\ \mu\text{s}$; $1\ \text{ms} \approx 186\ \text{miles}$ one-way.
- Jitter measures the variation of latency, e.g.:
  $$J_{\text{pp}} = t_{\max} - t_{\min}$$
  
Remember: latency = the delay; jitter = how that delay varies; hang time and anti-VOX are specific repeater/VOX features, not delay metrics.