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AA5X
11-11-2005, 01:16 AM
Knowlegeable fellows,

As a relatively new ham, I have a question about acceptable usage of SSTV oh HF. Specifically, I would like a proper interpretation of the IARU Region II bandplan and and if certain frequencies are actually reserved for SSTV.

IARU (Reg. II) says that frequencies between 14.225 adn 14.235 Mhz are meant for CW, SSB, SSTV and FAX. There is no specific "calling frequency" mentioned in this band plan, at least none that I have found.

I'm curious about the proper and courteous use of this range of frequencies and for 14.232MHz in particular, a frequency that appears in some charts as the "SSTV Calling Frequency".

On that point, a "calling frequency" suggests to me that it is to be used only briefly to establish with your correspondent a specific time and frequency for a continued QSO, whether it be by SSTV or any other mode. Yet, I have heard many people transmit SSTV on 14.232, and I have even heard one "gentleman" proclaiming quite vigourously that 14.232 is reserved for SSTV transmissions only.

Is this correct? Or as I assume, do you use 14.232 simply to make plans with your contact to use another frequency (14.225 - 14.235) for the SSTV QSO?

What if any of these frequencies is already in use by another mode, such as SSB? Is someone justified in demanding that the SSB QSO cease in favour of another, presumably "preferred" mode, or should the person demanding the QSY simply wait until the SSB QSO is finished, like any other well mannered operator?

I'd appreciate any references to "formal" operating procedure, if there are any, so I can read for my own satisfaction. The IARU website doesn't say much about this.

Regards,
Mike
AA5X

WA9SVD
11-11-2005, 01:45 AM
You will get a gazillion answers, all different.
Firstly, the ITU determines the Amateur allocations in the various regions. The FCC or corresponding agencies can be more restrictive as to the frequency allocations and modes available to Amateurs in their own country. (Thus, Canadian and Mexican Amateurs may have 'phone access to portions of Amateur bands that are still CW only for U.S. Amateurs.) That's an oversimplification, but an example.
The "band plans" as you surmise, are "Gentleman's (and Ladies') Agreements" that are meant to make mere disorder out of chaos. Certain frequencies are "strongly recommended" for some modes, to reduce interference from incompatible modes, such as SSTV and SSB. At the present time, the band plans do not carry the weight of law, but we all should act courteously and considerately and try to adhere to the band plan. And although it doesn't carry the weight of law, there is also the concept of "Good Amateur Practice," which should be followed. And that would seem to include following the band plans whenever possible. While no one Amateur (or group of Amateurs) "own" any particular frequency, good Amateur Practice would seem to require some compromise when conflicts occur.
Others will have varying opinions, including total disregard for any "bandplan."

AG3Y
11-11-2005, 02:20 AM
I have been interested in expanding into SSTV modes, and have been doing a lot of preparation toward achieving that goal by the new year. This preparation consists of gathering and preparing pictures in suitable format for sharing on the band, and listening to see where all the activity is taking place, and by whom.

My personal observation has been that 14.230 is generally used for conventional analog SSTV, and is usually headed up by a few fellows who have been using the mode for many years, who get together and swap pictures on a "take turns" basis. However, in the background I often hear other SSTV signals that are coming from stations far weaker and less copyable.

14.233 Mhz is generally used by another group of guys that are trying out the new Digital SSTV modes, although at times it becomes the second frequency for ad hoc "nets" to start up.

Very occasionally I will hear yet other activity usually around 14.227 Mhz, but this is not nearly as common as the other two frequencies.

There is hardly any other SSTV activity on 20 meters that I can hear with my minimal wire antennas, and SSTV seems to be largely occupied by fellows with full gallon amplifiers and very large beams up many feet in the air. But, like EME operation, you can successfully share pictures with the bigger stations because they have a great ability to pull your signal up out of the noise, too !

I have questions, myself about the digital SSTV modes, and have been asking for someone to give me "chapter and verse" where it is OK to use Digital modes to send pictures, and if it is legal to do that, why isn't it legal to use those same digital modes elsewhere in the band? My point is that the mode is digital, not analog as SSTV was originally defined. But I do not want to hijack the thread ! I still would like someone to answer that question, however!

73, Jim

LB1UE
11-11-2005, 08:23 AM
You will not be able to use these frequencies for SSB, as soon as you start, some SSTV dude tell you to QSY, if you start a discussion or continue using SSB, they'll jam you with SSTV.

G8ADD
11-11-2005, 09:09 AM
There is a lot of European SSTV activity on 14.233 with much mutual QRM and SSTV can be heard from 14.220 to 14.240. There is also frequent activity on 3.73 and occasionally on 7.045. However there is also a great deal of activity on 144.500 to 144.600, which is where I often hang out!

The problem I find with digital SSTV is that it is not easy to set up and there seem to be a lot of incompatible modes. What is needed is a digital equivalent of the easy to use MMSSTV!

73

Brian G8ADD

LB1UE
11-11-2005, 09:17 AM
Quote[/b] (G8ADD @ Nov. 11 2005,04:09)]The problem I find with digital SSTV is that it is not easy to set up and there seem to be a lot of incompatible modes. What is needed is a digital equivalent of the easy to use MMSSTV!
Even with MMSSTV you have alot of options to fail.

I have tried SSTV but I'm very uncomfortable with the wide offer of options.

It seems to be that SSTV is not standarized and that many developers has introduced way to much instead of optimizing the protocol.

By now I'm experimenting with MFSK modes and the good old PSK31 and RTTY.

Chip-64 does not work as expected and SSTV is too dynamic for my taste.

G8ADD
11-11-2005, 09:59 AM
I agree there seems to be far too many modes available on SSTV, every man and his dog seems to have had a go. The joy of MMSSTV is that it automatically selects the correct mode on receive and stays there so that you can transmit back in the same mode. Its free, too! It would be nice to have the same facility on digital SSTV so that I could forget the nuts and bolts and concentrate on the pictures! (Just kidding!)

I think most exchanges are in Martin 1.

73

Brian G8ADD

WA2ZDY
11-11-2005, 11:12 AM
Ah but for want of the old days, Venus monitors with P5 scopes . . . or even the ultra modern, $1500 (in 1978) Robot 400 and only one mode: 8 second black and white. And everyone was on 14230; life was much simpler then.

N5RFX
11-11-2005, 11:56 AM
Quote[/b] (AG3Y @ Nov. 09 2005,20:20)]I have questions, myself about the digital SSTV modes, and have been asking for someone to give me "chapter and verse" where it is OK to use Digital modes to send pictures, and if it is legal to do that, why isn't it legal to use those same digital modes elsewhere in the band? #My point is that the mode is digital, not analog as SSTV was originally defined. #
Jim,

Lets use 20 meters as the example. Don't get stuck on whether a mode is digital or analog. That makes no difference. 14.230 and 14.233 are in the image/phone portion of the 20-meter band. Look at the table in 97.305© go down until you find 20 meters and 14.15-14.35. Look to the right and you will see phone, image. Since we are talking about image emissions, look at 97.3©(3) for a definition of image. If you look at the emissions designators listed, both analog and digital emissions are authorized. You will see that the common denominator is that the third symbol of the emissions designator is a C. C means facsimile. SSTV emissions both analog and digital are facsimile emissions. So all is well.

Why can't I send images in the 14.00-14.15 MHz part of the band? Well letís look at the table in 97.305© and look at the Emission Types Authorized column and you will see RTTY, data. Go to 97.3©(3) and look at the definitions of RTTY and data. Nowhere in those definitions will you find the letter C in the third symbol of the emissions designators. When you send pictures, digital or analog you are sending a facsimile.

You will probably want a definition of facsimile. Part 97 does not give a definition of facsimile, but part 2 does.

Facsimile. A form of telegraphy for the transmission of fixed images, with or without half-tones, with a view to their reproduction in a permanent form.

Sending an image is a facsimile, so you need to find a part of any band where you are authorized to send images and the 3rd symbol of the emissions designator is a C.

73,

Mark N5RFX

AA5X
11-11-2005, 02:33 PM
Quote[/b] ]Others will have varying opinions, including total disregard for any "bandplan." -- WA9SVD


Indeed. Thanks for yours. It is reasonable.


Quote[/b] ]My point is that the mode is digital, not analog as SSTV was originally defined. But I do not want to hijack the thread ! I still would like someone to answer that question, however! -- AG3Y


That's a good question and not at all a thread-hijacker.


Quote[/b] ]You will not be able to use these frequencies for SSB, as soon as you start, some SSTV dude tell you to QSY, if you start a discussion or continue using SSB, they'll jam you with SSTV. -- LB1UE


I've seen that happen already.
It is my understanding that unless a frequency or range of frequencies is specifically reserved for a particular mode by a regulating authority (i.e., CW & data portions of a band as opposed the the phone/image/CW portion of the band) , then SSTV or any other mode operators should wait until the QSO is finished before they start transmitting. Well, some of these, er, "individuals" seem to have a different opinion, evidently assuming they have an exclusive right to transmit over a different-mode QSO in progress.
In my short tenure, I have come to see Amateur Radio as a gentleman's sport. However, some of them don't seem to be much of a gentleman.

Thanks to all those who offer advice, information and opinion. Please continue to contribute as you see fit.

Mike AA5X

WA2ZDY
11-11-2005, 02:51 PM
RFX, I too have pondered that question only due to Jim's questions. The reference to Part 2 explains it. That was the missing piece - to me anyway. Jim, I think he's nailed it.

Thanks Mark.

AG3Y
11-11-2005, 03:02 PM
While I realize that SSTV operators jeolously guard "their" frequencies, I wonder if it is not "the lesser of two evils" as contrasted with the scenerio of SSTV QSOs taking place all up and down the "Phone/SSTV" portion of the band? A SSTV signal eminating from a full gallon rig pumping into a 6 element beam at 100 feet is going to cover up anything else on the air, and rather than having several guys popping up at random spots on the band ( kinda/sorta like the "QRMBots" of Winlink infamy ), it might be better to respect the few SSTV calling frequencies that have been established, and go elsewhere to make "regular" SSB QSOs. There can be as many as 4 or 5 guys sending pictures to one another on one frequency, and several others "copying the mail" , and virtually every time I have listened in, there is an ad hoc "net" doing this very thing. I know that no-one "owns" any specific frequency, but imagine all that activity spread out all over the phone band!

73, Jim

AG3Y
11-11-2005, 03:06 PM
Chris, I tried to send a private message to Mark, thanking him for his concise explaination to that question, too, but somehow it ended up in the "bit-bucket" !

I believe that with this information, I will carefully forge ahead, but be ready to explain why I am using a Digital signal in the "Phone/Picture" portion of the band, if anybody questions it! "I'm sending PICTURES ! "

73, Jim

N5RFX
11-11-2005, 03:13 PM
Quote[/b] (AG3Y @ Nov. 10 2005,09:06)]I believe that with this information, I will carefully forge ahead, but be ready to explain why I am using a Digital signal in the "Phone/Picture" portion of the band, if anybody questions it! #"I'm sending PICTURES ! "

73, Jim
A similar explaination exists for why digital phone is where it is at in the 80 through 10 meter bands. These bands are segregated by the CONTENT of the emission, not the nature of the signals modulating the carriers.

73,

Mark N5RFX

AA5X
11-11-2005, 03:24 PM
Quote[/b] ]A SSTV signal eminating from a full gallon rig pumping into a 6 element beam at 100 feet is going to cover up anything else on the air, and rather than having several guys popping up at random spots on the band ( kinda/sorta like the "QRMBots" of Winlink infamy ), it might be better to respect the few SSTV calling frequencies that have been established, and go elsewhere to make "regular" SSB QSOs.


I agree completely! However, if an SSB or CW QSO is already in progress, even if it is on a "recommended" frequency, then the SSTV operator should wait until the QSO if finished before he blasts out his image.
In a recent event that I overheard, the SSTV fella did just that. First he got rather agitated over a DX pileup and claimed that 14.232 (specifically) was "an SSTV frequency by IARU gentleman's agreement", then in rather un-gentlemanly fashion declared that he would begin transmissions anyway ... and he proceded to do so.

I realise that this kind of behaviour is not exclusive to SSTV operators or any other modes, for that matter. I simply wonded if the guy had a valid, documented case for his claim, or if he was merely indulging the more common part of his personality.

I couldn't find a reference from IARU or any other organisation that specified any frequency in the 160, 75, 40, 20 and 15 meter bands as exlusive to, or even "strongly recommended" for, SSTV _OR_ phone.

Mike -- AA5X

AG3Y
11-11-2005, 03:32 PM
Digital SSTV has basically become transmission with two protocols, RDFT, which stands for Redundant Digital File Transfer, and DRM, which stands for Digital Radio Mondiale. Like so many other digital processes we use, these have been adapted from commercial developments, and a lot of information is available on the net, especially concerning DRM.

Although RDFM is a fine mode, I have seen almost all the stations that I can monitor switching to DRM. RDFM can be sent and received with an older sub-Ghz machine, but DRM needs computing power in excess of 1 Ghz and Win XP in order to work well, if at all ! I have not been successfull in getting DRM to work on my 400 Mhz machine, for instance.

The main frequency I have heard digital SSTV on is 14.233, with some very rare excursions away from that frequency.

The two programs I have seen being used the most are Digtrx and HamPAL. Digtrx will work with both protocols, but HamPAL is DRM only.

I'm just getting started in this myself, but these are some of the facts I've learned. Hope it helps!

73, Jim

AG3Y
11-11-2005, 03:43 PM
Mike, I'm not taking sides here, because I am basically a digital keyboard ragchewer, but I've heard it go both ways. I have heard numerous SSB operators, especially on contest weekends, hop right on top of a SSTV transmission in progress, and start yelling "CQ contest" without even acknowledging an existing transmission on the frequency!

Analog SSTV is 100% duty-cycle FSK, and nearly 3Khz wide ! Anybody trying to "argue" with the big boys using that mode are sure to lose!

Just as some people believe you can't legislate morality, I believe you can't legislate civility, either ! You either are a gentleman, or you are not. Unfortunately, there seem to be less and less gentlemen around, and the number seems to be shrinking almost daily!

73, Jim

AA5X
11-11-2005, 04:31 PM
Quote[/b] ]Mike, I'm not taking sides here, because I am basically a digital keyboard ragchewer, but I've heard it go both ways. I have heard numerous SSB operators, especially on contest weekends, hop right on top of a SSTV transmission in progress, and start yelling "CQ contest" without even acknowledging an existing transmission on the frequency! -- AG3Y


So have I! As for contests, much civility seems to get put aside for the sake of one more QSO. Oh, well. That's people for ya! As I mentioned before, this kind of behaviour is NOT exclusive to operators of any particular mode, band or region.

By the way, I'm not at all pursuing an "us against them" theme, nor do I see that anyone else in this thread has done so. All I've seen so far are reasonable opinions and good information. Hope it stays that way. In fact, I'm interested in SSTV myself, although it may be some time before I can translate interest into practice.


[QUOTE]Just as some people believe you can't legislate morality, I believe you can't legislate civility, either ! You either are a gentleman, or you are not. -- AG3Y
QUOTE]

I will admit to indulging in a wee whine about someone else's (naturally) misbehaviour. However, my goal is to gather information that guides the only behaviour that I can change: my own.

I use SSB exclusively, at the moment, and I have no problem avoiding the frequencies in question. I will take some satisfaction in having learned that transgressions from either "side" are issues of civility, not regulation.

Mike -- AA5X

VE7NOT
11-12-2005, 02:43 AM
I'll tell you whats not gentlemenly. I got a sstv signal on 40m push my needle to s-9 or more. I was supposed to meet a skid right there.

W5ALT
11-12-2005, 02:53 AM
That's why when we make skeds, we usually say "XXXX kHz and go up (or down) from there until there's a clear frequency."

W6TMI
11-12-2005, 05:40 AM
Quote[/b] (AG3Y @ Nov. 11 2005,08:02)]There can be as many as 4 or 5 guys sending pictures to one another on one frequency, and several others "copying the mail" , and virtually every time I have listened in, there is an ad hoc "net" doing this very thing. I know that no-one "owns" any specific frequency, but imagine all that activity spread out all over the phone band!
I've done that, leave the computer & radio on, you come back to all kinds of pictures. Seems later at night they get a little more racey too.

WA9SVD
11-12-2005, 09:00 PM
Quote[/b] (VE7NOT @ Nov. 11 2005,19:43)]I'll tell you whats not gentlemenly. I got a sstv signal on 40m push my needle to s-9 or more. I was supposed to meet a skid right there.
No offense, but the rest of the world isn't aware of your schedule, nor does it have to be. IF the frequency is already in use, the proper procedure is (by previous agreement for the schedule) to move up or down until you find a clear frequency. You and/or the other station need to agree on this in advance, but should be able to find each other if you just turn the VFO.

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