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Old 29-06-2013, 23:40   #31
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Re: USA Coastguard to stop monitoring 2182 and 2187.5

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so is a SSB useless now?
No...but there are useless people using it. I'm just bummed out that mini-skirts are out of style
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Old 30-06-2013, 04:01   #32
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Re: USA Coastguard to stop monitoring 2182 and 2187.5

SSB is not useless !
A good SSB installation with a Pactor Modem allows you to send email for almost no cost, plus you can get weatherfaxes for nothing, cruiser nets and so on.
I just installed an ICOM 710 with a Pactor Modem in my new boat, and put the Iridium phone in a cupboard.
It works very well...I wouldn't be with out it...
Remember when you call on the radio anyone can hear you, when you call on a sat phone, if no -one answers, no-one hears you !
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Old 08-07-2013, 01:47   #33
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Originally Posted by ka4wja View Post
Mark,
Sorry I didn't see this question earlier... 1) 2182khz was really never a good choice....well maybe in the 1950's....but since the late 60's/early 70's, most users found the HF freqs (the new "Hi-Seas" channels) to be much more useful....and in the 1970's there was a steady, and rapid, decline in use of the 2mhz/MF freqs, 2182khz, etc...

And, since January 1999, there has been NO requirement for VOICE radio watch / monitoring of 2182khz...by vessels at sea nor coast stations...
And, further, even years before that most merchant vessels and coast stations (except for the USCG), used "2182 watch receivers" which did NOT listen for "voice" signals, but rather for the "two-tone alarm signal", and only when they received this "alarm signal" did they un-squelch and then the watchstander could hear the vessel calling (although most of the time there was plenty of static as well!!!)

2) Since vertical antennas are/were required (by rule)on vessels for MF/2mhz, to maximize their groundwave communications abilities, for all practical purposes this also reduces the effectiveness of Near Vertical Incident Skywave (NVIS) communications...
And unfortunately, these vertical antennas are also very "noisy" receive antennas...

"Ground wave" communication range is very similar on 2mhz and 4mhz, and with 4mhz being much quieter AND usually having better NVIS signal strength, especially daytime...4mhz soon took over the functions of the old 2mhz MF maritime channels...

Overall daytime 2mhz (2182khz) communications, especially in tropical areas (with many hours of sunshine and hence high ionospheric "D" layer absorption...AND with scattered T-Storm activity on a regular basis), has always been poor, with ranges of usually 100 miles....
{In the mid/late 60's, I remember my Dad NEVER being able to raise "Miami" from the Exumas (200 - 250 miles away), nor even Nassau on some days...on 2mhz, using 150 watts and a 23' whip w/ a metal hull ground/counterpoise....and in 40 years of my own sailing/radio career, I've only tried 2mhz ONCE....and unsuccessfully...}

3) The GMDSS rules require vessels at sea to maintain a DSC radio watch on 2187.5, 8414.5khz, and "one other DSC frequency" (to be determined by the vessel's master, based on vessel location, route, time-of-day, radiowave propagation, weather, etc.)....
However, in actual practice all the GMDSS gear (and even the M-802) has six-channel DSC scanning receivers, so vessels that comply with GMDSS rules are monitoring/scanning all six DSC freqs (2187.5, 4207.5, 6312.0, 8414.5, 12577.0, and 16804.5), so if I were in need of assistance and desired to raise help, etc. from vessels in my area, I'd be sending out a 6-channel DSC distress...(but if I had to pick only one channel, it would 8414.5khz first, and then 4207.5 second....and if then no joy, I'd send out a 6-channel DSC distress signal...)

So, here it's 8mhz first, 4mhz second, and then probably 6mhz third...

4) As for recommendations for what HF frequencies to monitor, that's actually an easy answer!!!

For local/regional coverage...typically from 25/30 miles to 500 miles daytime, and longer ranges at night....
For VOICE monitoring:
8291khz, 4125khz, 6215khz....(these are 3 of the 6 GMDSS Voice Distress, Urgency, and Safety channels)

For DSC monitoring:
8414.5khz, 4207.5khz, 6312khz....(these are 3 of the 6 GMDSS DSC Distress, Urgency, and Safety channels)

Although exact ranges and communications capabilities (radiowave propagation) vary with time-of-day, time-of-year, solar flux, sun-spot activity, earth's magnetic field activity, etc....as well as local/regional T-storm activity affecting receive noise, etc....here are the typical ranges/capabilities...

Daytime should yield excellent coverage out to ~ 500 (or more) with fairly low-noise, on 8mhz....and from 100 - 2000 miles at night...
Daytime should yield good coverage out to 100 - 200 miles, with some noise, on 4mhz....and usually 25/30 miles - 1000 miles at night....
Coverage on 6mhz, typically falls in the middle between 4mhz and 8mhz....

5) My advice:
a) Make SURE that whatever your committee recommends, it INCLUDES DSC-watchkeeping....
This is not only part of the GMDSS (unlike voice radio watchkeeping) and will move whatever island is considering this into the 21st century!!
But is also increasingly being equipped on pleasure boats and is actually being understood and used by them!!!

And, depending on where the actual receiver is, it can allow even busy administrative staff / bureaucrats in an office to maintain a DSC watch, as the radio is silent until it gets a DSC message...

b) If there are budget concerns, an Icom M-802/At-140, with a 250' loop of wire for the main antenna (strung up horizontally, about 50' - 60' above ground, in a square or triangle shape), with one end of loop to "antenna" terminal on the AT-140 and the other end of the loop to the "ground" terminal...will work fine for this application....

And, a second similar loop antenna, just fed directly with coax, for the DSC receive antenna...is a great idea.....or, if space (and/or money) is at a premium a short, 40' sloping single wire antenna (fed directly with coax), is a good second choice for a DSC receive antenna....

This set-up allows 24/7 monitoring of all 6 Int'l DSC channels as well as whatever HF channels they choose to "Scan"....

c) If budget allows the Sailor / Thrane & Thrane series 6300 HF radios are really great...The 500 watt model 6350 is a super radio, but will set them back about $15,000 USD...
And they can put together complete GMDSS consoles and coast stations, etc...including antennas....
Loops, LPDA's, verticals, etc...all have their place/application....all it takes is money!!!

6) Have a look at the thread I started, a week ago, on the USCG and MF/2mhz comms on the SSCA disc boards...
http://www.ssca.org/forum/viewtopic.php?f=5&t=15726

Even years before this:

The USCG (and many others) has been discouraging the use of MF/2mhz maritime frequencies for many years now....

BTW, Mark, I envy you....being in on the ground floor of such a useful and humanitarian project, and dealing with RADIO at the same time!!!
How cool is that!!!

If you need more help, please let me know...
Fair winds...

John
s/v Annie Laurie
This is. Dummy question, but I. Am hoping you can help. How do I ensure if I push the distress DSC button on my icom 802 it transmits on all six DSC.channels? Or does it do this automatically?
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Old 08-07-2013, 15:20   #34
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M-802 DSC-Distress Signaling Information

Bazzer,
In my opinion, the only dumb questions are the ones not asked....

As for your specific questions...
Quote:
Originally Posted by bazzer View Post
This is. Dummy question, but I. Am hoping you can help. How do I ensure if I push the distress DSC button on my icom 802 it transmits on all six DSC.channels? Or does it do this automatically?
1) The M-802's manual leaves a lot to be desired, and I think I have referred to it as "crap" in the past...
But, if you read thru the manual with the radio in front of you, you can usually find out the answers....that is except when the manual and actual radio operations are 100% contradictory...



2) I did give a brief description of the M-802's DSC-Distress operation in the SSCA Disc Board thread that I referenced and provided a link to, above in this thread...
Quote:
Coincidently, this re-enforces the Icom M-802's default "simple-DSC-Distress" (activated by simply pressing and holding the red DISTRESS button for 5 seconds), which sends the DSC-Distress on 8414.5khz, and then switches to 8291.0khz USB for voice communications (contrary to what early versions of the manual state about it tuning to 2182khz)....
Although, I'd probably be making a "6-frequency DSC-Distress Call" (a bit more complex to activate....push DSC button, select Distress in the DSC Menu, press ENTER 3 times and then press-and-hold the red DISTRESS button for 5 seconds), which then sends a generic / undefined DISTRESS on each of the six international GMDSS DSC freqs....
But, I understand that many don't follow the links, nor read the reference material....





3) So, with the above in mind, here are the answers to your questions...
a) A "Simple" DSC-Distress Call is transmitted by simply pressing (and holding for 5 seconds) the red DISTRESS button (under the spring-loaded cover)...
The "Simple" DSC-Distress Call (with your MMSI # and position) is transmitted on 8414.5khz, and switches the radio to 8291.0khz (contrary to the manual) for Voice "traffic"....
This is "automatic", but is NOT a "six-freq DSC-Distress call...


b) A "Six-Frequency" DSC-Distress Call is selected using the DSC Menu...
You Push DSC to select DSC watch mode, push MODE to select the DSC menu, rotate the channel knob to select DISTRESS and then push ENTER three times....and then press (and hold for 5 seconds) the Red DISTRESS button (under the spring-loaded cover)...
After sending on all 6 freqs, it switches to 2182khz while waiting for an ACK and I assume the radio will then switch to the appropriate freq (corresponding the frequency your ACK is received on), although the manual isn't clear on that...


c) As you can see the "Six-Frequency DSC-Distress Call" is not automatic, unlike the "Simple DSC-Distress Call" you must select it....
And, as you can see 8mhz is the "default" for DSC and Voice "Distress Signaling" ("simple distress"), unless you select the "Six-Frequency" option...

While some may find this surprising, I do NOT....
As, for the past 40+ years the USCG (and others) have been discouraging the use of 2182khz (and other 2mhz/MF maritime freqs)....
Ever since I can remember, at least as far back as the early 1970's (my experience in HF maritime comms go back to 1973, and for 2mhz/MF maritime comms to the mid 60's), 8mhz has been used as a "default" day and night HF maritime band, with both USCG and other coast stations finding decent daytime coverage and excellent nighttime coverage (although noise-level limited at night)....and with the implementation of "2182 Alarm Receivers" nobody had to listen to 2mhz/MF anymore....so most (everyone in the developed / 1st World) seemed to move their focus to a quieter and more effective frequency band (8mhz)....although allowing 2mhz/MF to be used to fulfill the Sea Area A2 requirement, gave many 2nd / 3rd world nations the ability to participate in the GMDSS, most of the developed world was using higher (HF) frequencies...
(Australia was the one developed/1st world nation that specifically never deployed a 2mhz/MF system, and covered Sea Area A2 with HF stations from the outset...)
And, for many many years, those plying the Atlantic had the HF coast stations NMN (USCG, in Virgina) and GKA (Portishead Radio, in the UK), both of which were assigned ITU channel 816.... found they were usually within range of either (or both) day or night on 8mhz....
{Note, that while the USCG still uses their ITU duplex channels as their "working" channels and for weather broadcasts, they do NOT monitor these channels, but rather monitor the International GMDSS Voice and DSC Frequencies....my above ramblings about "816" are just for historical reference...}

Also, please understand that 8mhz is NOT always the "best" frequency band, and I hope you do NOT take this as what is implied here...
It is just that IF you cannot choose (or do not know how to choose) the most appropriate frequency for your maritime comms (at the specific time of day, time of year, sunspot cycle, T-storm activity, etc.), the 8mhz is a "default" band to work from....
AND, don't forget that while decent comms from 1000's of miles away is nice, what you may in fact be needing is to contact with someone CLOSE to you (within a few hundred miles) and this is where 8mhz daytime will be a good choice....(and not bad at night, but I'd probably also want to use 4mhz, etc. in case we have a skip zone on 8mhz at night...so if I have the time, I would select a "six-frequency DSC-Distress message"....


Follow this link for details of current USCG watchkeeping/monitoring....
MF/HF Distress and Safety Watchkeeping Schedule




Perhaps more detail than you expected, but I do hope this helps...

John
s/v Annie Laurie
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Old 08-07-2013, 16:31   #35
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Quote:
Originally Posted by ka4wja View Post
Bazzer,
In my opinion, the only dumb questions are the ones not asked....

As for your specific questions... 1) The M-802's manual leaves a lot to be desired, and I think I have referred to it as "crap" in the past...
But, if you read thru the manual with the radio in front of you, you can usually find out the answers....that is except when the manual and actual radio operations are 100% contradictory...

2) I did give a brief description of the M-802's DSC-Distress operation in the SSCA Disc Board thread that I referenced and provided a link to, above in this thread...But, I understand that many don't follow the links, nor read the reference material....

3) So, with the above in mind, here are the answers to your questions...
a) A "Simple" DSC-Distress Call is transmitted by simply pressing (and holding for 5 seconds) the red DISTRESS button (under the spring-loaded cover)...
The "Simple" DSC-Distress Call (with your MMSI # and position) is transmitted on 8414.5khz, and switches the radio to 8291.0khz (contrary to the manual) for Voice "traffic"....
This is "automatic", but is NOT a "six-freq DSC-Distress call...

b) A "Six-Frequency" DSC-Distress Call is selected using the DSC Menu...
You Push DSC to select DSC watch mode, push MODE to select the DSC menu, rotate the channel knob to select DISTRESS and then push ENTER three times....and then press (and hold for 5 seconds) the Red DISTRESS button (under the spring-loaded cover)...
After sending on all 6 freqs, it switches to 2182khz while waiting for an ACK and I assume the radio will then switch to the appropriate freq (corresponding the frequency your ACK is received on), although the manual isn't clear on that...

c) As you can see the "Six-Frequency DSC-Distress Call" is not automatic, unlike the "Simple DSC-Distress Call" you must select it....
And, as you can see 8mhz is the "default" for DSC and Voice "Distress Signaling" ("simple distress"), unless you select the "Six-Frequency" option...

While some may find this surprising, I do NOT....
As, for the past 40+ years the USCG (and others) have been discouraging the use of 2182khz (and other 2mhz/MF maritime freqs)....
Ever since I can remember, at least as far back as the early 1970's (my experience in HF maritime comms go back to 1973, and for 2mhz/MF maritime comms to the mid 60's), 8mhz has been used as a "default" day and night HF maritime band, with both USCG and other coast stations finding decent daytime coverage and excellent nighttime coverage (although noise-level limited at night)....and with the implementation of "2182 Alarm Receivers" nobody had to listen to 2mhz/MF anymore....so most (everyone in the developed / 1st World) seemed to move their focus to a quieter and more effective frequency band (8mhz)....although allowing 2mhz/MF to be used to fulfill the Sea Area A2 requirement, gave many 2nd / 3rd world nations the ability to participate in the GMDSS, most of the developed world was using higher (HF) frequencies...
(Australia was the one developed/1st world nation that specifically never deployed a 2mhz/MF system, and covered Sea Area A2 with HF stations from the outset...)
And, for many many years, those plying the Atlantic had the HF coast stations NMN (USCG, in Virgina) and GKA (Portishead Radio, in the UK), both of which were assigned ITU channel 816.... found they were usually within range of either (or both) day or night on 8mhz....
{Note, that while the USCG still uses their ITU duplex channels as their "working" channels and for weather broadcasts, they do NOT monitor these channels, but rather monitor the International GMDSS Voice and DSC Frequencies....my above ramblings about "816" are just for historical reference...}

Also, please understand that 8mhz is NOT always the "best" frequency band, and I hope you do NOT take this as what is implied here...
It is just that IF you cannot choose (or do not know how to choose) the most appropriate frequency for your maritime comms (at the specific time of day, time of year, sunspot cycle, T-storm activity, etc.), the 8mhz is a "default" band to work from....
AND, don't forget that while decent comms from 1000's of miles away is nice, what you may in fact be needing is to contact with someone CLOSE to you (within a few hundred miles) and this is where 8mhz daytime will be a good choice....(and not bad at night, but I'd probably also want to use 4mhz, etc. in case we have a skip zone on 8mhz at night...so if I have the time, I would select a "six-frequency DSC-Distress message"....

Follow this link for details of current USCG watchkeeping/monitoring....
MF/HF Distress and Safety Watchkeeping Schedule

Perhaps more detail than you expected, but I do hope this helps...

John
s/v Annie Laurie
John, thanks for the detailed reply, I will read carefully again and try to get to grips with it.
It seems to me that the 802, being a common tx/rx, should be able to be programmed to be able to transmit a six freq. dsc message. But it is not so we have to live with that.
Thanks again
Bazzer
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Old 08-07-2013, 17:38   #36
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ITU guidelines , say that where possible the 8mhz distress channel should be used, hence why the 802 is programmed. This is to avoid multiple parallel acknowledgment issues with multi channel DSC HF distress working. Its also the reason HF DSC mayday relaying is banned

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Old 02-09-2013, 15:15   #37
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Re: M-802 DSC-Distress Signaling Information

Quote:
Originally Posted by ka4wja View Post
Bazzer,
In my opinion, the only dumb questions are the ones not asked....

As for your specific questions... 1) The M-802's manual leaves a lot to be desired, and I think I have referred to it as "crap" in the past...
But, if you read thru the manual with the radio in front of you, you can usually find out the answers....that is except when the manual and actual radio operations are 100% contradictory...



2) I did give a brief description of the M-802's DSC-Distress operation in the SSCA Disc Board thread that I referenced and provided a link to, above in this thread...But, I understand that many don't follow the links, nor read the reference material....





3) So, with the above in mind, here are the answers to your questions...
a) A "Simple" DSC-Distress Call is transmitted by simply pressing (and holding for 5 seconds) the red DISTRESS button (under the spring-loaded cover)...
The "Simple" DSC-Distress Call (with your MMSI # and position) is transmitted on 8414.5khz, and switches the radio to 8291.0khz (contrary to the manual) for Voice "traffic"....
This is "automatic", but is NOT a "six-freq DSC-Distress call...


b) A "Six-Frequency" DSC-Distress Call is selected using the DSC Menu...
You Push DSC to select DSC watch mode, push MODE to select the DSC menu, rotate the channel knob to select DISTRESS and then push ENTER three times....and then press (and hold for 5 seconds) the Red DISTRESS button (under the spring-loaded cover)...
After sending on all 6 freqs, it switches to 2182khz while waiting for an ACK and I assume the radio will then switch to the appropriate freq (corresponding the frequency your ACK is received on), although the manual isn't clear on that...


c) As you can see the "Six-Frequency DSC-Distress Call" is not automatic, unlike the "Simple DSC-Distress Call" you must select it....
And, as you can see 8mhz is the "default" for DSC and Voice "Distress Signaling" ("simple distress"), unless you select the "Six-Frequency" option...

While some may find this surprising, I do NOT....
As, for the past 40+ years the USCG (and others) have been discouraging the use of 2182khz (and other 2mhz/MF maritime freqs)....
Ever since I can remember, at least as far back as the early 1970's (my experience in HF maritime comms go back to 1973, and for 2mhz/MF maritime comms to the mid 60's), 8mhz has been used as a "default" day and night HF maritime band, with both USCG and other coast stations finding decent daytime coverage and excellent nighttime coverage (although noise-level limited at night)....and with the implementation of "2182 Alarm Receivers" nobody had to listen to 2mhz/MF anymore....so most (everyone in the developed / 1st World) seemed to move their focus to a quieter and more effective frequency band (8mhz)....although allowing 2mhz/MF to be used to fulfill the Sea Area A2 requirement, gave many 2nd / 3rd world nations the ability to participate in the GMDSS, most of the developed world was using higher (HF) frequencies...
(Australia was the one developed/1st world nation that specifically never deployed a 2mhz/MF system, and covered Sea Area A2 with HF stations from the outset...)
And, for many many years, those plying the Atlantic had the HF coast stations NMN (USCG, in Virgina) and GKA (Portishead Radio, in the UK), both of which were assigned ITU channel 816.... found they were usually within range of either (or both) day or night on 8mhz....
{Note, that while the USCG still uses their ITU duplex channels as their "working" channels and for weather broadcasts, they do NOT monitor these channels, but rather monitor the International GMDSS Voice and DSC Frequencies....my above ramblings about "816" are just for historical reference...}
...
John
s/v Annie Laurie
John, this is just the information I was searching for. I had been urging the USCG to issue a Marine Safety Alert regarding the IC-M802's default to 2187.5 kHz, but if they truly do default to 8414.5 kHz as you say, would could have been a legitimate safety problem now longer is. Six frequency would have been a better default, but this is good enough, much better than 2MHz.

Can you confirm the change? Any idea when it occurred? (I noticed the currently posted instruction manual was copyrighted over a decade ago).

Thanks for posting this excellent background and information. Very helpful.

--joeh
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Old 02-09-2013, 15:50   #38
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Of course Portishead is long gone.


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Old 02-09-2013, 16:22   #39
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Re: USA Coastguard to stop monitoring 2182 and 2187.5

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No...but there are useless people using it. I'm just bummed out that mini-skirts are out of style
I've noticed that the online impression of SSB is seriously out of whack from its real world usage. If you're in "cruiser haunts" with 3g/4g access then SSB becomes a big klunky piece of gear. But for prolonged periods of off-the-grid and especially in tropical cyclone areas or other foul-weather conditions it can be downright critical.

Myself and another person on here both had our Iridium phone providers, two different companies, screw up our phones via billing or accounting bs while offshore or near offshore.

Being in a tropical cyclone area and not being able to get a forecast for a few days is spooky as all hell.
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