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

Go to page:  1  2  3  4  5  6  Notes  Appendix

 Copyright 2018 by TIGHAR, a non-profit foundation. No portion of the TIGHAR Website may be reproduced by xerographic, photographic, digital or any other means for any purpose. No portion of the TIGHAR Website may be stored in a retrieval system, copied, transmitted or transferred in any form or by any means, whether electronic, mechanical, digital, photographic, magnetic or otherwise, for any purpose without the express, written permission of TIGHAR. All rights reserved. Contact us at: info@tighar.org  •   Phone: 610.467.1937   •   JOIN NOW