RDF Analysis, page 2
Compilation of Potential Signal Sources
The potential signal sources are compiled in Table 1.

Table 1: Voice (A3) Capable Stations Within 15 kHz of 3105 kHz.

Station (Call Sign)
Freq kHz
Power watts
Latitude
Longitude
Function
Winslow, Arizona (KGTA)
3088
400
35-00 N
110-59 W
FA
Voronej, USSR (RFQH)
3090
250
51-17 N
38-53 E
FX
King Cove, Alaska (KMS)
3092.5
100
55-04 N
162-19 W
FC
Quarry Heights, Panama Canal Zone (WVL)
3100
75
8-57 N
79-33 W
FA
Melbourne, Australia (3AR) {5 x 620 kHz}
3100
70
38-47 S
144-58 E
BC
Navarin Mys, USSR (UGU1)
3100
40
62-17 N
179-04 E
FC
Stalino, USSR (RW26) {4 x 776 kHz}
3104
600
47-59 N
37-48 E
BC
Gardner Island (KHAQQ)
3105
50
4-40 S
174-32 W
aircraft
Oust-Kiakhta, USSR (UTC)
3105
60
50-13 N
106-17 E
FC, FX
San Diego area aircraft
3105
50
32-48 N
117-06 W
aircraft
Los Angeles area aircraft
3105
50
34-06 N
118-24 W
aircraft
San Francisco area aircraft
3105
50
37-48 N
122-24 W
aircraft
Seattle area aircraft
3105
50
47-47 N
122-18 W
aircraft
Billings, USSR (UQP1)
3110
40
69-53 N
176-05 E
FC
Oufa, USSR (UTP)
3110
15
54-43 N
55-37 E
FC
Anadyr, USSR (UIF1)
3120
150
64-50 N
177-22 E
FC
Nijne-Angarsk, USSR (UMA)
3120
100
55-46 N
109-35 E
FC
Oulan-Oude, USSR (UTR)
3120
150
50-00 N
107-35E
FC

Functions: BC: Broadcast station; FA: Aeronautical support station; FC: Coast station, providing communication with ships at sea or on inland waterway system; FX: Fixed point -to-point communications.

Each source in Table 1 was tested using the method described in Appendix A, to determine the feasibility of reception at each DF site under hypothetical ideal propagation conditions. This test provides a conservative basis for deciding whether the source can be ruled out as the potential origin of signals at a given DF site. If the source signal could not produce the required receiver input SNR under the ideal conditions of the test, then it could not do so under realistic propagation conditions. The test results are shown in Table 2.

Table 2: Signal Source Reception Feasibility Test Results

Rcvr Dist nmi
Source
Freq
kHz
Rcvr
Sel
Atten
dB
Mokapu
Midway
Wake
Howland
Dist
nmi
FS
SNR
dB
Dist
nmi
FS
SNR
dB
Dist
nmi
FS
SNR
dB
Dist
nmi
FS
SNR
dB
Winslow 3088
110
2615
-36
3384
-39
4401
-41
4194
-40
Voronej 3090
103
6364
-39
5712
-38
5781
-38
7205
-40
King Cove 3092
92
2040
-22
1765
-21
2613
-24
3371
-27
Quarry Hts 3100
23
4583
38
5566
37
6533
36
5709
37
Melbourne 3100
23
4803
38
4499
39
3642
41
3133
42
Navarin Mys 3100
23
2637
40
2097
43
2659
41
3704
38
Stalino 3104
0
6555
68
5852
69
5923
69
7369
67
Gardner Island 3105
0
1815
68
1941
43
1810
68
350
68
Oust-Kiakhta 3105
0
4645
60
3653
63
3408
63
4883
60
San Diego acft 3105
0
2303
66
3105
63
4138
61
3853
61
Los Angeles acft 3105
0
2228
66
3021
63
4053
61
3848
61
San Fran acft 3105
0
2081
67
2775
64
3825
61
3697
62
Seattle acft 3105
0
2325
66
2791
64
3805
61
3954
61
Billings 3110
23
3062
39
2539
41
3079
39
4179
39
Oufa 3110
23
5939
29
5175
31
5176
31
6612
28
Anadyr 3120
103
2777
-34
2226
-32
2797
-34
3865
-41
Nijne-Angarsk 3120
103
4415
-40
3500
-38
3364
-38
4826
-41
Oulan-Oude 3120
103
4571
-39
3604
-36
3349
-36
4825
-39

The receiver selectivity attenuation corresponding to the source frequency is shown, together with the source distance from each DF site, and the free-space SNR resulting from the test. Recalling that the threshold input SNR, for detecting the presence of an A3 signal without distinguishing any words is 41 dB for this analysis, the results shown in Table 2 can be sorted into three categories. The SNR for signals from some sources robustly exceed the threshold at some or all DF sites; some marginally exceed or fall below the threshold; and some fall far below the threshold.

Retaining the first two categories and deleting the third yields the following table of potential sources retained for further consideration in the analysis.

Table 3: Signal Sources Retained for Further Analysis

Source
Freq
kHz
Rcvr
Sel
Attend
dB
Mokapu
Midway
Wake
Howland
Dist
nmi

FS
SNR
dB
Dist
nmi

FS
SNR
dB
Dist
nmi

FS
SNR
dB
Dist
nmi

FS
SNR
dB
Quarry Hts
3100
23
4583
38
5566
37
6533
36
5709
37
Melbourne
3100
23
4803
38
4499
39
3642
41
3133
42
Navarin Mys
3100
23
2637
40
2097
43
2659
41
3704
38
Stalino
3104
0
6555
68
5852
69
5923
69
7369
67
Gardner Island
3105
0
1815
68
1941
43
1810
68
350
68
Oust-Kiakhta
3105
0
4645
60
3653
63
3408
63
4883
60
San Diego acft
3105
0
2303
66
3105
63
4138
61
3853
61
Los Angeles acft
3105
0
2228
66
3021
63
4053
61
3848
61
San Fran acft
3105
0
2081
67
2775
64
3825
61
3697
62
Seattle acft
3105
0
2325
66
2791
64
3805
61
3954
61
Billings
3110
23
3062
39
2539
41
3079
39
4179
39


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