8. When using a doublet, we must consider its height above ground.
For a 0 to 25-mile circuit using sky wave, we must erect the antenna
We might have to
vary the height from 15 to 30 feet. For short distance sky wave, we
The highest frequency will determine our antenna
For example: A quarter wave at 12 MHz is 19 feet.
doublet antenna should not exceed 19 feet in height. As we lower the
Therefore, you might have to lengthen the antenna.
Your SWR meter
will indicate whether you need to lengthen it or not.
9. You're probably thinking, "Now wait a minute! I don't have a
choice of frequencies.
I use what is listed in the CEOI." You're
However, if those frequencies don't work, inform your
frequency manager at Division, Corps, Army, or Theater, and you will
be given additional frequencies. The bottom line is that you are not
stuck with any frequency that doesn't work. Remember also that there
is no such thing as a sole-user frequency.
You will share your
frequency with hundreds of users throughout the World. The following
or international broadcast stations located there:
2 - 3 MHz
4.75 - 4.95 MHz
5.95 - 6.2 MHz
9.50 - 9.77 MHz
11.70 - 11.97 MHz
15.10 - 15.45 MHz
17.70 - 17.90 MHz
21.45 - 21.75 MHz
25.60 - 26.10 MHz
These bands might seem to work during the day. At night, you might
experience interference submit a M1J1 report, then request another
frequency, until you get one that will work.
Don't keep using the
same frequency when you know it won't work. Keep reporting it until
you receive a better frequency. There are always spare frequencies.