Emerg. Freq. Modes ?

[BOBRR]

Hello,

If this is the wrong Forum for this, I apologize. Just let me know, and I'll re-post.

I always have trouble in knowing the correct mode for an item.
Lots of databases, but almost none of them bother to state the mode to use for reception.

Will blame my ignorance on Sr. Citizen status now.

a. Anyone know the mode for: "Global Emergency Centers" frequencies (several, between 3.750 to 21.360) ?
(USB or AM ?)

b. Is there a really good composite list (I tried, really) of Emerg. Frequencies that also gives the correct reception mode for ?
Interested primarily in Land, Aero., and Federal

Or, might someone, please, if practical, list what, in general, are the modes used for the various emerg. freq's.

Much thanks,
Bob

 

[AK9R]

If this is the wrong Forum for this, I apologize. Just let me know, and I'll re-post.

Do not repost. Doing so would be known as "cross-posting" which is generally not allowed in the RadioReference Forums. If you want your post moved to a different forum, click the "Report" link at the bottom of your message and ask the moderators to move it.

 

[nd5y]

a. Anyone know the mode for: "Global Emergency Centers" frequencies (several, between 3.750 to 21.360) ?
(USB or AM ?)

I have never heard of a Global Emergency Center. What is that?
The frequencies you listed are for ham radio.

b. Is there a really good composite list (I tried, really) of Emerg. Frequencies that also gives the correct reception mode for ?
Interested primarily in Land, Aero., and Federal

What exactly do you mean by Emergency Frequency? Used by who?

Any organization that is authorized or licensed to use radio can assign one or more of its own frequencies for emergency use. There is not going to be a comprehensive list.

The only thing close would be the aviation emergency/guard frequencies 121.5 and 243.0 MHz both are AM. Military avation also has 40.5 MHz FM as a guard frequency. VHF marine radio distress/calling is CH 16 or 156.8 MHz FM.

 

[a417]

@BOBRR are you referring to this type of stuff? As @nd5y seemed to allude to, your question contains some fundamental misconceptions and might not be the easy answer you are looking for.

Considering that first page refers to SOLAS-(19)14 and SOLAS-29 era decisions, and this summarizes the early adoption of specific modes in radiotelephony...there apparently could be AM/FM or USB - depending on what was in vogue at the time.

 

[Blueliner]

This might not answer Bob's question unless he has an SDR. But, the new release of the SDR Connect's waterfall gives a pretty clear indication of the visible signal's mode. Example is LSB has a sharp right side signal limit with a bit of signal trailing off to the left. Select LSB and line it up with that right edge of the signal and you're spot on. Same with USB except the reverse, the sharp edge of the signal is on the left. The Connect seems to sense the signal and switches the mode to what's appropriate, but not always when looking for AM signals, there may be the odd USB or LSB or even CW nearby. The waterfall lets me usually select the correct mode.
Here is what I am referring to. Be aware, I am a total nugget on this and this may be common rudimentary knowledge but something I've come to notice.

 

[merlin]

Across all HF maritime frequencies, 2182 Khz is monitored for distress. Mode on that frequency is AM or DSB with carrier.
14300 Khz allows a mariner in distress to use any means or mode possible to attract attention.
4207.5, 6312, 8414.5, 12577, and 16804.5 use DSC (digital selective calling) This allows for GPS location.
4207.5 , DSC test calls will automatically acknowleged by all USCG stations except Guam.
All other maritime services use USB.
VHF distress channel is 16 and FM across the band.

HF Distress and USCG Contact Frequencies | Navigation Center

Frequencies for the Global Maritime Distress and Safety System (GMDSS). GMDSS Radio Survey Blog

Frequencies for the Global Maritime Distress and Safety System (GMDSS)

gmdsstesters.com

 

[hill]

Merlin,

The USCG hasn't had a watch on 2182 for many years. Many other countries also did away with watches on this frequency.

Also it had been USB and not AM.

See link below.

Coast Guard will stop using 2182 kHz as an international distress frequency

The U.S. Coast Guard has decided to terminate its use of radiotelephone Medium Frequency (MF) 2182 kHz, which was first designated more than 65 years ago,

www.fishingandboats.com

 

[merlin]

Merlin,

The USCG hasn't had a watch on 2182 for many years. Many other countries also did away with watches on this frequency.

Also it had been USB and not AM.

See link below.

Coast Guard will stop using 2182 kHz as an international distress frequency

The U.S. Coast Guard has decided to terminate its use of radiotelephone Medium Frequency (MF) 2182 kHz, which was first designated more than 65 years ago,

www.fishingandboats.com

That is what I had thought but wasn't certain. Thanks for the heads up. I know GMDSS is the current distress system and it is getting old.