Seatty Decoder

[Saint]

First time decoding DCS System,

I have downloaded the Seatty decoder and have set it up to decode any DSC DISTRESS traffic on 2187.5 kHz, I want to see it I can receive any traffic on this frequency, I know there are several other frequencies that belong to the DSC system, I am wondering if I would have a better chance of picking up anything just sitting on 2187.5 or should I sit on another DSC frequency, any help appreciated,
Steve

 

[ka3jjz]

As with any HF application you need to consider the effects of propagation on the frequency. During the day, that frequency isn't going to propagate very well - the D layer of our ionosphere will absorb the signal, and the most you would get would probably be ground wave type coverage. The rules that govern propagation doesn't change just because the service does.

I would check the higher freqs (above 10 Mhz or so) during the day, lower at night. Mike

 

[Saint]

As with any HF application you need to consider the effects of propagation on the frequency. During the day, that frequency isn't going to propagate very well - the D layer of our ionosphere will absorb the signal, and the most you would get would probably be ground wave type coverage. The rules that govern propagation doesn't change just because the service does.

I would check the higher freqs (above 10 Mhz or so) during the day, lower at night. Mike

Thanks for the information, I will try different frequencies and see If I can pick up something on the DSC System, I am trying out Seatty Decoder and have been decoding Fax's and it works flawless, except when the signal gets weak but it works great.
Steve

 

[ka3jjz]

Saint, one other thing I didn't mention is the antenna. Sure even a 40-50 foot wire will hear something on 2 Mhz, but at freqs this low, it's rather inefficient.

If you want to go this low, a better antenna is in order. Otherwise, as I mentioned previously, stay up higher, considering the time of day and its effects due to propagation...Mike

 

[KK4LQX]

FYI

Effective 01 August, 2013, the U. S. Coast Guard will terminate its radio guard of the international voice distress, safety and calling frequency 2182 kHz and the international digital selective calling (DSC) distress and safety frequency 2187.5 kHz. Additionally, marine information and weather broadcasts transmitted on 2670 kHz will terminate concurrently.

The Coast Guard will continue to maintain a continuous watch on VHF FM channel 16 (156.8 MHz) and on existing voice and DSC frequencies in the 4/6/8/12 MHz bands as described in the Coast Guard Navigation Center website http://www.navcen.uscg.gov/?pageName=cgcommsCall.

This safety alert is provided for informational purposes only and does not relieve any domestic or international safety, operational or material requirement. Developed by the Spectrum Management and Telecommunications Policy Division (COMDT CG-652), USCG Headquarters, Washington, D.C..

 

[ka3jjz]

While it's true that the CG is no longer actively monitoring 2187.5, it remains one of the internationally-assigned frequencies, and several recent logs about odd traffic on this freq on the UDXF yahoo group bears this out. However, a longer antenna (up to a point, natch) will do better on receiving 2 Mhz signals. A 45 or 50 foot antenna (which is what many people start off with) will work but not particularly well on 2 Mhz. It's just too short to be electrically efficient

Mike