Download  Print this page

Honeywell KHF 1050 Pilot's Manual page 23

Hf communications system with ps440 control display unit
Hide thumbs

Advertisement

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.
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.
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.
Frequency (kHz)
4000
Propagation (Miles)
Min
Hours After Sunset
1
50
2
100
3
100
4
100
5
100
6
100
7
100
8
250
9
250
10
250
11
100
Hours After Sunrise
1
100
2
0
3
0
4
0
5
0
6
0
7
0
8
0
9
0
10
0
11
0
12
0
13
50
Table 1A - Typical Frequency Propagation Spring And Summer
Revision 0 Mar/2003
8000
Max
Min
Max
250
200
1000
600
250
1500
600
250
2000
800
250
2500
1000
250
2500
1500
400
3000
1500
500
3500
2000
750
4000
2500
750
4000
2500
750
4000
1000
500
2500
500
400
2000
100
400
2000
100
250
1500
100
250
1500
100
250
1500
100
250
1500
100
250
1500
100
250
1500
100
250
1500
100
250
1500
100
150
200
150
250
150
19
12000
Min
Max
500
3500
500
3500
500
3500
500
1000
500
1500
500
2500
500
3500
500
3500
500
3500
500
3500
500
500
3500
500
500
3500
750
500
3500
KHF 1050/PS440 Pilot's Guide
16000
Min
Max
750
6000
750
6000
750
4000
750
4000
750
4000
750
4000
750
4000
750
6000
750
6000
750
6000

Hide quick links:

Advertisement

Table of Contents
loading

  Related Manuals for Honeywell KHF 1050

This manual is also suitable for:

Primus hf 1050Ps440