Honeywell International Inc. KHF1050 Manuel D’Utilisation
One feature that will be particularly useful when a trial and error method
is used to find an HF frequency which is working well. This is the sys-
tem’s capability to be programmed by the pilot with 100 channels using
the PS440 Control Display Unit. Rather than having to select the four to
six digits each time you want to try another frequency, you can prepro-
gram the frequencies you need to contact a particular ground station.
Then if you call and fail to get through, you just change to another chan-
nel.
is used to find an HF frequency which is working well. This is the sys-
tem’s capability to be programmed by the pilot with 100 channels using
the PS440 Control Display Unit. Rather than having to select the four to
six digits each time you want to try another frequency, you can prepro-
gram the frequencies you need to contact a particular ground station.
Then if you call and fail to get through, you just change to another chan-
nel.
NOTE: It is advisable to program at least three frequencies for each sta-
tion you plan to contact, in case one frequency suddenly becomes unus-
able. During times of solar disturbances, a useable frequency can fade
out in less than a minute. And the “window” of useable frequencies can
shift rapidly during solar disturbances or during sunset and sunrise when
the level of ionization in the ionosphere is changing rapidly.
tion you plan to contact, in case one frequency suddenly becomes unus-
able. During times of solar disturbances, a useable frequency can fade
out in less than a minute. And the “window” of useable frequencies can
shift rapidly during solar disturbances or during sunset and sunrise when
the level of ionization in the ionosphere is changing rapidly.
Tables 1A and 2A show typical propagation distances due to reflection
from the ionosphere for various frequencies during different hours of the
day and for different seasons of the year. It may prove helpful in select-
ing the optimum HF frequency for the communications distance your
operation requires.
from the ionosphere for various frequencies during different hours of the
day and for different seasons of the year. It may prove helpful in select-
ing the optimum HF frequency for the communications distance your
operation requires.
Revision 0 Mar/2003
KHF 1050/PS440 Pilot’s Guide
19
Table 1A - Typical Frequency Propagation Spring And Summer
Frequency (kHz)
4000
8000
12000
16000
Propagation (Miles)
Min
Max
Min
Max
Min
Max
Min
Max
Hours After Sunset
1
50
250
200
1000
500
3500
750
6000
2
100
600
250
1500
500
3500
750
6000
3
100
600
250
2000
500
3500
4
100
800
250
2500
5
100
1000
250
2500
6
100
1500
400
3000
7
100
1500
500
3500
8
250
2000
750
4000
9
250
2500
750
4000
10
250
2500
750
4000
11
100
1000
500
2500
Hours After Sunrise
1
100
500
400
2000
2
0
100
400
2000
3
0
100
250
1500
4
0
100
250
1500
500
1000
5
0
100
250
1500
500
1500
6
0
100
250
1500
500
2500
750
4000
7
0
100
250
1500
500
3500
750
4000
8
0
100
250
1500
500
3500
750
4000
9
0
100
250
1500
500
3500
750
4000
10
0
100
250
1500
500
3500
750
4000
11
0
100
150
500
500
3500
750
6000
12
0
200
150
500
500
3500
750
6000
13
50
250
150
750
500
3500
750
6000
KHF1050 PG R0 3/21/03 3:22 PM Page 19