New DigiMode — ROS. 1st QSO this evening.

...snip...

 

I guess you haven't noticed that ROS has two outstanding characteristics that brought on the discussion you do not want to allow others to have:

1. ROS is another ultra-wide digital mode. ( 2.2kHz. ) - Which means that it is far too wide for responsible, regular or widespread use on HF frequencies.

2. ROS is a spread-spectrm mode, which means that it is not legal for US operators to use on HF in the first place.

Note that the USA provides world leadership with its PART97 regulations. The fact that some other countries with smaller amateur radio populations do not follow that lead is not a good reason to abandon reason.

In the world of digital amateur radio, the worst lids on the planet are those who insist upon using ultra-wide signals on HF where there simply isn't enough room to use them without causing harmful interference. Note that these lids are also the only group in amateur radio who propound transmitting without listening first as being acceptable operating procedure.

All other amateurs have too much common sense and good character to have anything to do with that kind of behavior.

- Just as most participants in internet forums know better than to try to tell other folks what they can and cannot talk about. - Get the picture?

 

So where i can meet ROS comunity on 20 and 40m band ?
it's sound interesting to test

 

I'm not sure what 48KHz bandwidth modems have to do with ROS, which is 2.2KHz bandwidth, but whatever, I have to disagree with you. The 15m and 12m bands have been opening up recently, as I'm sure you've noticed, and it won't be long before 10m does too. The trouble is that once established these wideband modes won't go away when people want to start using these bands for SSB, CW, PSK31 etc.

Whilst I'm sure the point you made about ROS being described as a spread spectrum mode is valid, surely this is an issue you should be taking up with your regulatory authorities? Perhaps if your ARRL was less intent on turning ham radio into an emergency service it might do something about lifting some of the restrictions hams in the land of the free have to work under?

I think the biggest problem facing a 2.2kHz wide weak signal mode on just about any HF band is not regulatory. I was listening on 80m last night and I heard a W, a TF, two Gs and two DLs all calling at more or less the same time. I heard the W reply to two stations, and I heard one of those stations call CQ again half way through his call to them. I did not hear anyone actually complete a contact during the time I was listening.

The mode does work and I have completed 3 contacts so far but the more people use it the more space they will need and I don't think there is enough space for many people to be using 2.2KHz wide digimodes on any of the HF bands, with the possible exception of 10m. The trouble is, as WSPR has already shown, when 10m is dead it is dead to any form of long distance propagation and therefore not very interesting.

 

I gave the ROS mode a blast at 16 baud on 40m and found it virtually impossible to resolve strong signals due to the nearby CW signals.
The 1 baud did the trick but it cleared the CW operators from the ROS bandwidth (Not good at all) this is a mode that will cause mayhem on HF if it is used IMO

I made 2 contacts using ROS and wasn't really impressed, it's pleasant to listen to its melodic tones but that's as far as it goes with me.

I'll stick to BPSK

 

IANAM (I am not a moderator). It was obvious they have a beef going way back. As I look back it was probably better just to fogettaboutit and watch them dig themselves deeper.

 

This issue DOES warrant discussion. There are a number of modes that use close to ROS's bandwidth, including MT63/2000 (2Khz), Winmor, MFSK/64 (1.4Khz), Pactor and others.

Andy K3UK has come up with a proposal that is fairly accommodating to various bandplans already in use:

http://www.obriensweb.com/bandmap.html

Bandwidth-heavy modes are already an issue, and segmenting band plans into segments that are defined by a mode's bandwidth would go a long ways into helping reduce stomping of narrow modes. A digital bandplan would be the best way in my opinion to not only reduce narrowband/wideband congestion, but also further experimentation. Wide-band mode programmers would have a "sandbox" to experiment with new modes, like ROS without the added issue of bandwidth coming up.

In regards to "ultra-wide bandwidth" modes, I don't see them having much room when the band is full. The amateur code requires one to "listen" before transmitting, and so ultra-wide bandwidth modes could still work on the band in question if the two operators scan the band segment in question before initiating a QSO. It could be accomplished when bands are in little use and they follow procedure. However as the sun cycle reignites higher frequencies, it will be more and more difficult to find a band segment that isn't crowded!

 

This is precisely why I think a digital bandplan that brings the wideband modes into their own segment is worth pursuing, like K3UK's proposed plan. It would reduce accidental stompings!

The "Spread Spectrum" issue is a valid one, and in my opinion (and many on the digitalradio yahoo group) strictly a Part 97 legalese issue. ROS performs frequency hopping within its 2.2Khz bandwidth, meaning it won't jump all around the band like some SS techniques.
Also, the "hopping code" is a public one. The only real difference between ROS and other digital modes like OLIVIA, MT63, FSK16 and others is that the chosen frequency to be transmitted is chosen by an independent math formula, rather than just the message. In practice, decoding any of them is exceedingly difficult unless you know the documentation behind them.

As such, the label "Spread Spectrum", although technically it may apply to ROS, it shouldn't be an issue given the mode's similarities to many digital modes already in existence. There has already been a petition sent to the FCC to reform this issue. Hopefully the "Spread Spectrum" legalese will be pushed aside and a more reformed language will be included to allow open, published amateur experimentation of different digital modes without un-necessary legalese stumbling blocks.

 

I'm not a lawyer, and I haven't even read about the modem in question.

However, as a practical matter, it is not called spread-spectrum, if the bandwidth is the size, or smaller than an SSB bandwidth signal.

The FCC could care less. There are other modes that fall into this same category.

Spread-Spectrum is a mode, where the signal is spread across multiple SSB type bandwidths. For example, the modem we use in our station, frequency hops across 3 MHz of bandwidth in the HF spectrum, or 10's of MHz in the VHF/UHF spectrum, and 300 MHz in the L-band.

Spread-Spectrum techniques used inside a SSB bandwidth signal are not included in the definition of Spread-Spectrum the FCC uses.

 

I am inclined to agree with K5OKC on this matter. To take it a step further even, FHSS is a misnomer for this mode. FHSS relies on rapidly switching a carrier among many frequency channels. In ROS the carrier is not switching at all; rather, it is using a modulation shift based on an algorithm rather than an ascii or baudot code. To my reading of part 97, it seems the issue revolves on whether there is sufficient public documentation of the data encoding, at this time.

 

FHSS still obeys the Shannon limit. FHSS does not increase the bit rate. It merely allows multiple stations to share a portion of the RF spectrum while minimizing collisions via pseudo-random carrier frequency hopping sequences.

 

Well, I looked at the web page. There's a couple PDF files, but neither say anything about what is going on, or outline the coding scheme. I don't think this thing will progress much until they describe the mode better.

It's also rather obsolete, with VB6 used to build it.

I had to download a RAR extractor, and what I got could easily fit in a ZIP. I don't know why europeans like to pay money for an archiver, but they do.

Finally, I don't really like files sending emails. This thing has a lot of bloat for a proof of concept.

I'll have to wait for more docs before I let it run on my network.

 

In that case it isn't working, because if another station starts up while you are half way through receiving something being sent to you the program starts decoding the newcomer - result no QSO.

 

I don't know why they switched to a .rar file. All the previous versions were .zips. A lot of users last night were complaining about corrupted .zips. Perhaps that's why they switched. Here's some info on how to open .rar files if anyone needs it. I don't think you need to buy any program just to extract it.

Personally I'm passing on that version too, but not because of the archive format. I think there are quite a few problems to be resolved with the use of this mode, and with the software. It's great that hams are experimenting and developing new modes. But I think it has been released to the public prematurely.

 

Very good point. In PSK31 you choose a frequency, or frequencies inside the audio passband that you want to communicate with.

If you have 20 FH stations inside the audio passband, you can't select the one you want by frequency. You need to select a hop code.

Thus, as a minimum, each user needs to select a hop code from a selection, and then other users would see which hop codes are active, and be able to select the ones they want to communicate with.

The hop codes being a virtual audio frequency in the passband.