There are several things to keep in mind when using MARS Radio:
Call on the primary frequency first. All MARS stations monitor the primary frequency both day and night. The secondary frequency is night US Time or when you are close to the MARS station and he can not hear you on the primary frequency. Some MARS station monitor the primary and secondary frequency at the same time.
Give your approximate location if not classified. The MARS station can often improve reception if the operator knows which way to aim the antenna. Having the antenna pointed correctly can make the difference between "Loud and Clear" and "Weak, Barely Readable". The location does not have to be specific. The state or country if not the US or Canada is sufficient. The MARS station might give his location and ask which direction you are from him.
Call multiple times. To avoid confusion, the only station that will answer you on the first call is the "Net Control" station. If "Net Control" does not hear you, other stations will respond after your second radio call. Also, if you are answered by an operator other than the net control, he will usually first contact the NCS to see who will handle your patch. Talk distinctly. Another station may be assigned to you based on your location and rotation of the operators.
EXAMPLE RADIO CALL:
"MARS RADIO. MARS RADIO, REACH 123, NORTH ATLANTIC, OVER"
If after calling several times you do not get any response, you may wish to try again in 30 minutes when propagation may be different or try the secondary frequency. You may be moved to another frequency for better communication or if there is active traffic on the primary.
Please pass this information on to other crews.