Sunday, November 28, 2010

Jam tomorrow

I have not been keeping up with the development of the controversial ROS digital mode as for reasons given in earlier posts I decided it was not something I wanted to use. However a recent post in the Yahoo digital modes group brought to my attention a development that seems rather alarming. The ROS software has recently included an anti-jamming switch the purpose of which is described as "improves rejection against strong CW and Beacons interferences."

Polite usage of the amateur bands require that you check the frequency is in use before making a call so no-one should be jamming anybody. Furthermore, no-one should be using ROS in the CW or beacon sub bands. So what exactly is the purpose of this switch and why should anyone need it?

Perhaps an inkling of what may be going to happen can be drawn from some of the comments relating to the performance of the anti-jam switch, for example:
  • "The New ROS/2000 passed the test successfully during the CW Contest last weekend."
  • "More test with the New ROS/2000 in other hostile environment. This time during a PSK63 Contest on Sunday."
As I said all along (indeed, this was my original objection to the use of this mode) ROS is just too wide for use in the narrow digital allocations of the HF bands. There just isn't the space for it, unless it remains a niche, occasionally used mode, which clearly its developer and supporters don't intend it to be. As another comment in the ROS forum states: "The bands will fill up once people realize how good this mode is."

The development of anti-jam techniques suggest that ROS is being readied to engage in war with users of other modes. When users can't find a clear frequency they will just operate on top of other modes. The principal claimed advantage of the wide ROS mode is that it enables contacts to be made under similar weak signal conditions to JT65A but that it permits keyboard chats to take place rather than the basic exchange of signal reports and locators. So it appears that a vast swathe of spectrum space is going to be made unusable for other modes simply so that people can exchange brag files.

We need strict regulation of digital modes on the amateur bands. The days of gentlemen's agreements are over. There are too many modes competing for limited spectrum space, and too many hams who aren't gentlemen.

6 comments:

PE4BAS, Bas said...

Hi Julian, I don't know what the switch is doing exactly. From the comments it has something to do with DSP? Anyway, it does mean that ROS is capable or going to be to trx over another mode without interference on its own system. The intention or invention is not that bad if you use ROS. But clearly for other users of HF it's trouble. Probabely this comment will not make Mr. Ros happy but if there is no room for it at the HF digital allocations may be there is place for this mode on the 11 Mtr band?? ;-)

73, Bas

Oops, this will get me a definite ban on the use of the ROS mode...

Julian said...

Curiously enough I saw that an 11m frequency has been suggested for ROS. I suppose that is for users of illegal (in EU) SSB. Actually there would be plenty of space on 10m but I can't imagine even ROS would make QSOs possible on 10m in current conditions.

PE4BAS, Bas said...

Hi Julian, you never know. A good friend of me operating 11 Mtr SSB did e-mail me 2 weeks ago telling me he made everyday QSO's to VK. He's only using a 3 elem. yagi on about 8 Mtrs and I guess 100W. So, any other mode would be possible...also on 10 and 12m. 73, Bas

Paul - PC4T said...

Hello Julian, I wish I had a anti jamming switch on my JT65-HF or Fldigi for PSK. We should respect the band-plans even when it's a gentlemen's agreement. This weekend it was not possible to do some PSK-ing or JT65 because of the CQ WW DX Contest. So, I joined the contest, what else could I do? 73 Paul

Julian said...

I agree, Paul, and it surprises me that you should need to make this comment because I would have thought CW operators were the most gentlemanly of all hams.

Do CW contesters stray into the digital modes segment because they never use digital modes and are unaware that the digital segment starts there, because they believe it is acceptable to ignore the band plan during a contest, or because they just don't care?

Paul - PC4T said...

Hi Julian, I hope that it will be that they are unaware, so I can forgive easily. ;-) 73 Paul