[digitalradio] Re: Try some JT65A
I keep returning to DM780 as my main digi mode program. It does NOT support Olivia 32/500 or 64/500. I'm running v5.0 beta. I think one of the older releases had an option to set the tones/baud parameters separately. I think MixW will work on these Olivia sub modes. Are these sub modes are slower than the staple 16/500? 73, Steve N6VL --- In digitalradio@yahoogroups.com, sholtofish sho...@... wrote: Andy, Another very sensitive mode to try is Olivia 32/500 or even 64/500. Tony and I managed perfect copy at QRP levels with a very poor path. Bit faster than JT65 too. 73 Sholto
[digitalradio] Re: KH6TY's Post
Skip, The problem with ROS is that the frequency shift is by a method too similar to that used in VFO-shifting spread spectrum (frequency hopping) transceivers so to the observer, there is no difference. Could you elaborate on this please? Tony -K2MO - Original Message - From: KH6TY To: digitalradio@yahoogroups.com Sent: Sunday, February 21, 2010 10:14 PM Subject: Re: [digitalradio] FCC Technology Jail: ROS Dead on HF for USA Hams RF is RF and the FCC does not care how the frequency expansion is done, whether by VFO shift or supressed carrier tone shift. I am shocked that Bonnie does not understand that simple principle. For example, true FSK is done by VFO shift, but FSK is also done on SSB by tone shift. The result is identical, the only difference being that the transceiver does not have to be linear with FSK shift, but it does with tone frequency shift to prevent splatter. The problem with ROS is that the frequency shift is by a method too similar to that used in VFO-shifting spread spectrum (frequency hopping) transceivers, so to the observer, there is no difference. It is the frequency hopping that makes ROS spread spectrum, and unfortunately, that is against the FCC regulations. If it were not, there could possibly be spread spectrum transceivers using tone shifts much wider than an IF bandwidth, even using soundcards, just like SDR's spectrum displays use. In that case, more than one voice channel would be taken up for the benefit of the SS user, to the detriment of adjacent stations, or even those farther away, if there were no other limitations on bandwidth utilized. 73 - Skip KH6TY W2XJ wrote: Bonnie you have a Ham unfriendly addenda. Say what you like but at the end of the day it is BS. From: expeditionradio expeditionra...@yahoo.com Reply-To: digitalradio@yahoogroups.com Date: Mon, 22 Feb 2010 01:09:14 - To: digitalradio@yahoogroups.com Subject: [digitalradio] FCC Technology Jail: ROS Dead on HF for USA Hams Given the fact that ROS Modem has been advertised as Frequency Hopping Spread Spectrum (FHSS), it may be quite difficult for USA amateur radio operators to obtain a positive interpretation of rules by FCC to allow use of ROS on HF without some type of experimental license or waiver. Otherwise, hams will need an amendment of FCC rules to use it in USA. Sadly, this may lead to the early death of ROS among USA hams. If ROS Modem had simply provided the technical specifications of the emission, and not called it Spread Spectrum, there would have been a chance for it to be easily adopted by Ham Radio operators in USA. But, the ROS modem designer is rightfully proud of the design, and he lives in a country that is not bound by FCC rules, and probably had little or no knowledge of how his advertising might prevent thousands of hams from using it in USA. But, as they say, You cannot un-ring a bell, once it has been rung. ROS signal can be viewed as a type of FSK, similar to various other types of n-ary-FSK presently in widespread use by USA hams. The specific algorithms for signal process and format could simply have been documented without calling it Frequency Hopping Spread Spectrum (FHSS). Since it is a narrowband signal (using the FCC and ITU definitions of narrowband emission = less than 3kHz) within the width of an SSB passband, it does not fit the traditional FHSS description as a conventional wideband technique. It probably would not have been viewed as FHSS under the spirit and intention of the FCC rules. It doesn't hop the VFO frequency. It simply FSKs according to a programmable algorithm, and it meets the infamous 1kHz shift 300 baud rule. http://www.arrl.org/FandES/field/regulations/news/part97/d-305.html#307f3 This is a typical example of how outdated the present FCC rules are, keeping USA hams in TECHNOLOGY JAIL while the rest of the world's hams move forward with digital technology. It should come as no surprise that most of the new ham radio digital modes are not being developed in USA! But, for a moment, let's put aside the issue of current FCC prohibition against Spread Spectrum and/or Frequency Hopping Spread Spectrum, and how it relates to ROS mode. Let's look at bandwidth. There is the other issue of bandwidth that some misguided USA hams have brought up here and in other forums related to ROS. Some superstitious hams seem to erroneously think that there is an over-reaching bandwidth limit in the FCC rules for data/text modes on HF that might indicate what part of the ham band to operate it or not operate it. FACT: There is currently no finite bandwidth limit on HF data/text emission in USA ham bands, except for the sub-band and band edges. FACT: FCC data/text HF rules are still mainly based on content of the emission, not bandwidth. New SDR radios have the potential to transmit and receive wider bandwidths than the traditional 3kHz SSB passband. We will
[digitalradio] Re: Considerate Operation: CW and JT65A
Andy I am both frequent another forum that is CW based. The subject came up over the weekend about a two tone mode in the vicinity of 14077 kHz. Andy pointed out it was probably JT65A. The other commenter found it annoying with two other CW signals in the bandpass. I almost jumped into the discussion, but held back. I think the commenter was inferring the digital signal was interfering with the CW signals. It all depends on who was there first. Also it wasn't certain that the two CW ops and the digital ops could hear each other, although the commenter could hear all three. I think sound card mode ops can easily look for nearby signals, on the waterfall, for the period of a few minutes to get an idea of the activity. The same is not true for CW ops if they have narrow filters. Some rigs have dual peak filters for RTTY. There could be a signal in between the filter peaks and the op could never hear a signal in between. A couple years ago, I answered a local buddy calling CQ on 40 meter PSK31. After the QSO, one op made a scathing comment about his qso in progress being qrm'ed. I didn't reply. From my perspective, I had heard a CQ and answered it. My local buddy should have heard the other qso as well. I did email the guy and apologized. It is much easier for the CW op to hear other signals when they are running full or semi breakin. Digital ops don't have that luxury, as we transmit a few minutes on and few minutes, depending on the speed. Perhaps TOR mode ops could hear other signal between the bursts, if they are not automated. CW ops usually call QRL? to see if the frequency is in use. How do digi ops do that? How does the digi op reply to a CW QRL? query? There will always be QRM, even with the best of intentions. We should try to minimize as much as possible. I operate both digital and CW and don't see an easy answer. 73, Steve N6VL
Re: [digitalradio] Re: Try some JT65A
Steve wrote: I keep returning to DM780 as my main digi mode program. It does NOT support Olivia 32/500 or 64/500. I'm running v5.0 beta. I think one of the older releases had an option to set the tones/baud parameters separately. Version 4.1 of DM780 does allow these Olivia modes to be selected. That's what I use if I'm going to use Olivia. Dave (G0DJA)
Re: [digitalradio] Re: Considerate Operation: CW and JT65A
Steve wrote: The same is not true for CW ops if they have narrow filters. On all the rigs I've owned the filters are selectable. Are there any radios that have only very narrow CW filters, or are the 'on/off' buttons difficult to operate? ;-) Taking tongue out of cheek, as I do enjoy CW as well, saying that people with digital modes can, and should, listen 1st and look at the frequencies around them, the same should be true for CW operators. In my opinion. Dave (G0DJA)
Re: [digitalradio] Re: KH6TY's Post
The comment was made that ROS is different from a FFSS mode that accomplishes the spreading by shifting the VFO frequency. The point is that in a SSB transmitter, the RF frequency is equal to the suppressed carrier frequency plus (USB) or minus (LSB) the tone frequency. So it does not matter how the RF frequency gets moved, either by VFO shift of a carrier, or by tone shift on a SSB transmitter. Unfortunately, Jose went to great lengths to establish that ROS is a FHSS mode. He does this by using different tone frequencies but the result is the same as shifting a VFO frequency in a traditional FHSS transmitter. The RF is still shifted according to a pseudo-random code in both cases. To the observer, there is no difference except perhaps in the degree of spreading used. It is just unfortunate that the FCC regulations were undoubtedly written in order to keep really wide FHSS transmissions from covering all of a band, and in the aggregate, have a multitude of stations seriously interfering with many narrow bandwidth modes. By keeping the spreading within the bandwidth of a SSB phone signal, Jose sidesteps the problem, but it still takes a clarification, or exemption, or modification, of the rules as written to make it possible for us to use ROS on HF. In other words, the FCC could say that as long as the spreading is no wider than a phone signal, it is legal to use SS on HF, but this would have to be done in advance of regular use. If not, I could use a SDR with FHSS capability and spread over 100 KHz for whatever benefit that might bring and if others did that, seriously interfere with the use of the band by many other stations on a different base frequency. Since there is lots of room on UHF compared to HF, FHSS is already legal there and a reasonable degree of spreading is not of so much importance. This is why ATV is only allowed on UHF. It is so wide that it takes a wide band to leave room for others to share and operate. 73 - Skip KH6TY Tony wrote: Skip, The problem with ROS is that the frequency shift is by a method too similar to that used in VFO-shifting spread spectrum (frequency hopping) transceivers so to the observer, there is no difference. Could you elaborate on this please? Tony -K2MO - Original Message - From: KH6TY To: digitalradio@yahoogroups.com Sent: Sunday, February 21, 2010 10:14 PM Subject: Re: [digitalradio] FCC Technology Jail: ROS Dead on HF for USA Hams RF is RF and the FCC does not care how the frequency expansion is done, whether by VFO shift or supressed carrier tone shift. I am shocked that Bonnie does not understand that simple principle. For example, true FSK is done by VFO shift, but FSK is also done on SSB by tone shift. The result is identical, the only difference being that the transceiver does not have to be linear with FSK shift, but it does with tone frequency shift to prevent splatter. The problem with ROS is that the frequency shift is by a method too similar to that used in VFO-shifting spread spectrum (frequency hopping) transceivers, so to the observer, there is no difference. It is the frequency hopping that makes ROS spread spectrum, and unfortunately, that is against the FCC regulations. If it were not, there could possibly be spread spectrum transceivers using tone shifts much wider than an IF bandwidth, even using soundcards, just like SDR's spectrum displays use. In that case, more than one voice channel would be taken up for the benefit of the SS user, to the detriment of adjacent stations, or even those farther away, if there were no other limitations on bandwidth utilized. 73 - Skip KH6TY W2XJ wrote: Bonnie you have a Ham unfriendly addenda. Say what you like but at the end of the day it is BS. From: expeditionradio expeditionra...@yahoo.com Reply-To: digitalradio@yahoogroups.com Date: Mon, 22 Feb 2010 01:09:14 - To: digitalradio@yahoogroups.com Subject: [digitalradio] FCC Technology Jail: ROS Dead on HF for USA Hams Given the fact that ROS Modem has been advertised as Frequency Hopping Spread Spectrum (FHSS), it may be quite difficult for USA amateur radio operators to obtain a positive interpretation of rules by FCC to allow use of ROS on HF without some type of experimental license or waiver. Otherwise, hams will need an amendment of FCC rules to use it in USA. Sadly, this may lead to the early death of ROS among USA hams. If ROS Modem had simply provided the technical specifications of the emission, and not called it Spread Spectrum, there would have been a chance for it to be easily adopted by Ham Radio operators in USA. But, the ROS modem designer is rightfully proud of the design, and he lives in a country that is not bound by FCC rules, and probably had little or no knowledge of how his advertising might prevent thousands of hams from using it in USA. But, as they say, You cannot un-ring a bell, once it has been rung.
Re: [digitalradio] Re: Considerate Operation: CW and JT65A
Now Dave, C'mon I have the narrow cw filter on my 706mk II The on / off button is a challenge. Loljust messing with you now. No offence. On a serious note though, even with my limited cw surely it is possible to answer a QRL back in cw, providing you at least have 2 wires and a paper clip to slap together if no key hi hi. (I do have some keys now, but I used a paper clip on the desk for my 1st cw qso ) Also isn't there something about sending your ID in SSB /CW anyway. I also read this and thought, hey most digi mode software will send an cw id and or you could use computer generated cw to check if the frequency is in use. I am so desperate to get my cw receiving up to scratch so I can use it freely, I wish we had still had to take the test back in 2004 to be honest. Maybe we could sked a qrs contact some afternoon / evening. Toby MM0TOB ---Original Message--- From: Dave Ackrill Date: 22/02/2010 11:00:08 To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Re: Considerate Operation: CW and JT65A Steve wrote: The same is not true for CW ops if they have narrow filters. On all the rigs I've owned the filters are selectable. Are there any radios that have only very narrow CW filters, or are the 'on/off' buttons difficult to operate? ;-) Taking tongue out of cheek, as I do enjoy CW as well, saying that people with digital modes can, and should, listen 1st and look at the frequencies around them, the same should be true for CW operators. In my opinion. Dave (G0DJA)
Re: [digitalradio] Re: Considerate Operation: CW and JT65A
I often look at the CW signal on the waterfall when I hear one close to me. My view is...if his signal is not exactly on the same part of the waterfall as mine, we are OK. I can notch him out and he can do the same to me. A couple of hundred Hz separation should be all we need. On Mon, Feb 22, 2010 at 6:14 AM, Toby Burnett ruff...@hebrides.net wrote: Now Dave, C'mon I have the narrow cw filter on my 706mk II The on / off button is a challenge. Loljust messing with you now. No offence. On a serious note though, even with my limited cw surely it is possible to answer a QRL back in cw, providing you at least have 2 wires and a paper clip to slap together if no key hi hi. (I do have some keys now, but I used a paper clip on the desk for my 1st cw qso ) Also isn't there something about sending your ID in SSB /CW anyway. I also read this and thought, hey most digi mode software will send an cw id and or you could use computer generated cw to check if the frequency is in use. I am so desperate to get my cw receiving up to scratch so I can use it freely, I wish we had still had to take the test back in 2004 to be honest. Maybe we could sked a qrs contact some afternoon / evening. Toby MM0TOB *---Original Message---* *From:* Dave Ackrill dave.g0...@tiscali.co.uk *Date:* 22/02/2010 11:00:08 *To:* digitalradio@yahoogroups.com *Subject:* Re: [digitalradio] Re: Considerate Operation: CW and JT65A Steve wrote: The same is not true for CW ops if they have narrow filters. On all the rigs I've owned the filters are selectable. Are there any radios that have only very narrow CW filters, or are the 'on/off' buttons difficult to operate? ;-) Taking tongue out of cheek, as I do enjoy CW as well, saying that people with digital modes can, and should, listen 1st and look at the frequencies around them, the same should be true for CW operators. In my opinion. Dave (G0DJA)
Re: [digitalradio] Re: Considerate Operation: CW and JT65A
Toby Burnett wrote: Now Dave, C'mon I have the narrow cw filter on my 706mk II The on / off button is a challenge. Loljust messing with you now. No offence. On a serious note though, even with my limited cw surely it is possible to answer a QRL back in cw, providing you at least have 2 wires and a paper clip to slap together if no key hi hi. (I do have some keys now, but I used a paper clip on the desk for my 1st cw qso ) Also isn't there something about sending your ID in SSB /CW anyway. I also read this and thought, hey most digi mode software will send an cw id and or you could use computer generated cw to check if the frequency is in use. Yes, I had an IC706MKIIG for a long while. Maybe it was the poor location of the filter button that made me get rid of it? HI. Here in the UK the requirement for CW ID was removed several years ago and the latest UK licence is a much simpler and very cut down document. There's not even a legal requirement to keep a logbook anymore and the /M or /A or /P suffixes are 'recommendations' that people 'may' use. These are mentioned in the notes to the licence, not even in the main body... If anyone wants to see a modern UK licence, a draft copy is available on the OFCOM website, go to http://www.ofcom.org.uk/radiocomms/ifi/licensing/classes/amateur/Licences/samplelicence07.pdf Dave (G0DJA)
Re: [digitalradio] Re: Considerate Operation: CW and JT65A
Dave, I knew about the logbook but not the cwid or /m /p etc hmm. I am getting out of touch. The only time I can see not using a log book though is when /m but that's just me. I love looking back over the past 6 years at old qso's and seeing if I have a (new one hi hi ) When I was first licensed March the 5th 2004 everything was a new one and I think for the new breed of M6 / M3's etc it would be a shame for them to not keep a log. Ok I don't log every single net on 160m or VHF for example, but pretty much every contact still goes in the log, I bet you are the same. VHF is such a shame up here in the outer Hebrides, took the puppy for a walk yesterday and up the hill I can see most of the isle of Lewis for 2m, not a single reply even through GB3IG which I though was quite sad for a Sunday afternoon. There must be at least 25 operators on the island and the repeater can work some distance out to the NW Scotland. I don't have a 2m antenna up at the MO and this was quite sad to not make a single contact. Oh well. Toby Desperate for CW. lol ---Original Message--- From: Dave Ackrill Date: 22/02/2010 11:34:35 To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Re: Considerate Operation: CW and JT65A Toby Burnett wrote: Now Dave, C'mon I have the narrow cw filter on my 706mk II The on / off button is a challenge. Lol just messing with you now. No offence. On a serious note though, even with my limited cw surely it is possible to answer a QRL back in cw, providing you at least have 2 wires and a paper clip to slap together if no key hi hi. (I do have some keys now, but I used a paper clip on the desk for my 1st cw qso ) Also isn't there something about sending your ID in SSB /CW anyway. I also read this and thought, hey most digi mode software will send an cw id and or you could use computer generated cw to check if the frequency is in use. Yes, I had an IC706MKIIG for a long while. Maybe it was the poor location of the filter button that made me get rid of it? HI. Here in the UK the requirement for CW ID was removed several years ago and the latest UK licence is a much simpler and very cut down document. There's not even a legal requirement to keep a logbook anymore and the /M or /A or /P suffixes are 'recommendations' that people 'may' use. These are mentioned in the notes to the licence, not even in the main body... If anyone wants to see a modern UK licence, a draft copy is available on the OFCOM website, go to http://www.ofcom.org uk/radiocomms/ifi/licensing/classes/amateur/Licences/samplelicence07.pdf Dave (G0DJA)
Re: [digitalradio] Re: Considerate Operation: CW and JT65A
Toby Burnett wrote: Dave, I knew about the logbook but not the cwid or /m /p etc hmm. I am getting out of touch. The only time I can see not using a log book though is when /m but that's just me. I love looking back over the past 6 years at old qso's and seeing if I have a (new one hi hi ) I do tend to keep a record of stations that I work, but I no longer log every CQ call, as we used to have to do. I guess it's a case of not being a legal requirement, but a nice record to have. OK on 2M, it can be the same down here at times. 2M SSB only seems to get going in the summer and those of us that prefer CW tend to have to wait for Aurora and Meteor Scatter to really kick in. Anyway, I think were getting off topic for this thread now. Dave (G0DJA)
Re: [digitalradio] Re: Considerate Operation: CW and JT65A
I agree with that, and I see modern day rigs have a tremendous amount of filtering capability. I'm talking about the likes of the 756 pros / FT1000 s / ts2000's etc etc and other such radios that would take a small mortgage for me. I notice that these have variable band pass filters and the like that could probably narrow the pass band to a few 10's of hertz enough for a single cw or bpsk31 signal. I suspect that these work on TX also ? Like me and many many others who run older equipment without all the bells and whistles though, as you say. I was always taught to listen first and then listen again. Although just remember that we don't all have the super dsp and notch filters on our radio's. Out of interest, do common filters work on TX or just rx, and if not why?? ---Original Message--- From: Andy obrien Date: 22/02/2010 11:32:36 To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Re: Considerate Operation: CW and JT65A I often look at the CW signal on the waterfall when I hear one close to me My view is...if his signal is not exactly on the same part of the waterfall as mine, we are OK. I can notch him out and he can do the same to me. A couple of hundred Hz separation should be all we need. On Mon, Feb 22, 2010 at 6:14 AM, Toby Burnett ruff...@hebrides.net wrote: Now Dave, C'mon I have the narrow cw filter on my 706mk II The on / off button is a challenge. Loljust messing with you now. No offence. On a serious note though, even with my limited cw surely it is possible to answer a QRL back in cw, providing you at least have 2 wires and a paper clip to slap together if no key hi hi. (I do have some keys now, but I used a paper clip on the desk for my 1st cw qso ) Also isn't there something about sending your ID in SSB /CW anyway. I also read this and thought, hey most digi mode software will send an cw id and or you could use computer generated cw to check if the frequency is in use. I am so desperate to get my cw receiving up to scratch so I can use it freely, I wish we had still had to take the test back in 2004 to be honest. Maybe we could sked a qrs contact some afternoon / evening. Toby MM0TOB ---Original Message--- From: Dave Ackrill Date: 22/02/2010 11:00:08 To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Re: Considerate Operation: CW and JT65A Steve wrote: The same is not true for CW ops if they have narrow filters. On all the rigs I've owned the filters are selectable. Are there any radios that have only very narrow CW filters, or are the 'on/off' buttons difficult to operate? ;-) Taking tongue out of cheek, as I do enjoy CW as well, saying that people with digital modes can, and should, listen 1st and look at the frequencies around them, the same should be true for CW operators. In my opinion. Dave (G0DJA)
Re: [digitalradio] ROS Advantage?
Aside from the legal aspect, does anyone have an opinion as to whether the limited hopping (within the 3khz that it hops) helps the robustness of the waveform? If it makes a tremendous difference, maybe we should all work to get it accepted. Howard K5HB From: J. Moen j...@jwmoen.com To: digitalradio@yahoogroups.com Sent: Sun, February 21, 2010 9:13:50 PM Subject: Re: [digitalradio] FCC Technology Jail: ROS Dead on HF for USA Hams Bonnie's note describes the US/FCC regulations issues regarding ROS and SS really well. It's the best description of the US problem I've seen on this reflector. After reading what seems like hundreds of notes, I now agree that if ROS uses FHSS techniques, as its author says it does (and none of us has seen the code), then even though it 1) uses less 3 kHz bandwidth, 2) does not appear to do any more harm than a SSB signal and 3) is similar to other FSK modes, it is not legal in FCC jurisdictions. As Bonnie points out, ROS doesn't hop the VFO frequency, but within the 2.5 bandwidth, it technically is SS. This would be true if ROS used 300 Hz bandwidth instead of 2.5 kHz, but hopped about using FHSS within the 300 Hz bandwidth. So I have to agree the FCC regs are not well written in this case. Regarding the corollary issue of US/FCC regulations focused on content instead of bandwidth, I'm not competent to comment. Jim - K6JM - Original Message - From: expeditionradio To: digitalradio@ yahoogroups. com Sent: Sunday, February 21, 2010 5:09 PM Subject: [digitalradio] FCC Technology Jail: ROS Dead on HF for USA Hams Given the fact that ROS Modem has been advertised as Frequency Hopping Spread Spectrum (FHSS), it may be quite difficult for USA amateur radio operators to obtain a positive interpretation of rules by FCC to allow use of ROS on HF without some type of experimental license or waiver. Otherwise, hams will need an amendment of FCC rules to use it in USA. Sadly, this may lead to the early death of ROS among USA hams. If ROS Modem had simply provided the technical specifications of the emission, and not called it Spread Spectrum, there would have been a chance for it to be easily adopted by Ham Radio operators in USA. But, the ROS modem designer is rightfully proud of the design, and he lives in a country that is not bound by FCC rules, and probably had little or no knowledge of how his advertising might prevent thousands of hams from using it in USA. But, as they say, You cannot un-ring a bell, once it has been rung. ROS signal can be viewed as a type of FSK, similar to various other types of n-ary-FSK presently in widespread use by USA hams. The specific algorithms for signal process and format could simply have been documented without calling it Frequency Hopping Spread Spectrum (FHSS). Since it is a narrowband signal (using the FCC and ITU definitions of narrowband emission = less than 3kHz) within the width of an SSB passband, it does not fit the traditional FHSS description as a conventional wideband technique. It probably would not have been viewed as FHSS under the spirit and intention of the FCC rules. It doesn't hop the VFO frequency. It simply FSKs according to a programmable algorithm, and it meets the infamous 1kHz shift 300 baud rule. http://www.arrl. org/FandES/ field/regulation s/news/part97/ d-305.html# 307f3 This is a typical example of how outdated the present FCC rules are, keeping USA hams in TECHNOLOGY JAIL while the rest of the world's hams move forward with digital technology. It should come as no surprise that most of the new ham radio digital modes are not being developed in USA! But, for a moment, let's put aside the issue of current FCC prohibition against Spread Spectrum and/or Frequency Hopping Spread Spectrum, and how it relates to ROS mode. Let's look at bandwidth. There is the other issue of bandwidth that some misguided USA hams have brought up here and in other forums related to ROS. Some superstitious hams seem to erroneously think that there is an over-reaching bandwidth limit in the FCC rules for data/text modes on HF that might indicate what part of the ham band to operate it or not operate it. FACT: There is currently no finite bandwidth limit on HF data/text emission in USA ham bands, except for the sub-band and band edges. FACT: FCC data/text HF rules are still mainly based on content of the emission, not bandwidth. New SDR radios have the potential to transmit and receive wider bandwidths than the traditional 3kHz SSB passband. We will see a lot more development in this area of technology in the future, and a lot more gray areas of 20th century FCC rules that inhibit innovation and progress for ham radio HF digital technology in the 21st century. Several years ago, there was a
[digitalradio] Re: Considerate Operation: CW and JT65A
Hi Andy et al., I agree with your statement. On 80m I observe some stupid fellow trying to QRM with carrier howling and cw-dots on 3576 kHz when there is JT65 ,mainly between 18z and 21z. I have suffered absolutely no broken QSO even if that QRM was in the middle of the signal or spot on the guide tone, but I can imagine that a less experienced CW-op could get confused by jt65 or similar mode overlaying his QSO. vy73 Fred DL6XAZ --- In digitalradio@yahoogroups.com, Andy obrien k3uka...@... wrote: I often look at the CW signal on the waterfall when I hear one close to me. My view is...if his signal is not exactly on the same part of the waterfall as mine, we are OK. I can notch him out and he can do the same to me. A couple of hundred Hz separation should be all we need. On Mon, Feb 22, 2010 at 6:14 AM, Toby Burnett ruff...@... wrote:
Re: [digitalradio] ROS Advantage?
Howard, After monitoring 14.101 continuously for two days, I find the following: 1. CW signals (of narrow width, of course) during this past weekend contest often disrupted decoding, and it looks like it was not desensitization due to AGC capture, as the ROS signals on the waterfall did not appear any weaker. 2. Pactor signals of 500 Hz width, outside the ROS signal, that capture the AGC, do desensitize the receiver and cause loss of decoding, as expected. Passband tuning takes care of that problem however. 3. Pactor signals which have the same degree of darkness as the ROS carriers, and occur within the upper third of the ROS signal, cause loss of decoding, and it is not possible to fix the problem with passband tuning, as trying to do that appears to take away enough of the ROS signal that the degree of frequency hopping used is insufficient to overcome. Receiver is the IC-746Pro. 4. If more than one ROS signal is present on the frequency, ROS will decode one of them - apparently the strongest one - and the weaker one is blanked out until the stronger one goes away and the the weaker one is decoded. 5. Compared to Olivia 16-500, for example, the width of the ROS signal seems to be a disadvantage as far as handling QRM is concerned. Five Olivia 16-500 signals will fit in the same space as one ROS signal needs, so QRM, covering the top 40% of the ROS signal, for example, would probably not disrupt any of three Olivia signals in the bottom 60% of the ROS signal bandwidth. In other words, the wide bandwidth required for ROS to work is a disadvantage because IF filtering cannot remove narrower band QRM signals that fall within the area of the ROS signal, but IF filtering can remove the same QRM from the passband that has been narrowed to accept only an Olivia signal. A much wider expansion or spectrum spread might reduce the probability of decoding disruption, but that also makes the signal wider still and more susceptible to additional QRM. The advantage of FHSS appears to be more in favor of making it hard to copy a traditional SS signal unless the code is available, than QRM survival, but on crowded ham bands, it looks like a sensitive mode like Olivia or MFSK16, because it is more narrow, and filters can be tighter, stands a better chance of surviving QRM than the ROS signal which is exposed to more possibilities of QRM due to its comparatively greater width. The mode sure is fun to use and it is too bad it does not appear to be as QRM resistant as hoped, at least according to my observations. Another problem is finding a frequency space wide enough to accommodate several ROS signals at once so there is no cross-interference. It is much easier to find space for five Olivia or MFSK16 signals than for even two ROS signals. These are only my personal observations and opinions. Others may find differently. I still plan to find out if ROS can withstand the extreme Doppler shift and flutter on UHF which just tears up even moderately strong SSB phone signals. Olivia appears to be the best alternative mode to SSB phone we have found so far and sometimes provides slightly better copy than SSB phone, but for very weak signals, CW still works the best. Even though the note is very rough sounding, as in Aurora communications, CW can still be copied by ear as it modulates the background noise. 73 - Skip KH6TY Howard Brown wrote: Aside from the legal aspect, does anyone have an opinion as to whether the limited hopping (within the 3khz that it hops) helps the robustness of the waveform? If it makes a tremendous difference, maybe we should all work to get it accepted. Howard K5HB *From:* J. Moen j...@jwmoen.com *To:* digitalradio@yahoogroups.com *Sent:* Sun, February 21, 2010 9:13:50 PM *Subject:* Re: [digitalradio] FCC Technology Jail: ROS Dead on HF for USA Hams Bonnie's note describes the US/FCC regulations issues regarding ROS and SS really well. It's the best description of the US problem I've seen on this reflector. After reading what seems like hundreds of notes, I now agree that if ROS uses FHSS techniques, as its author says it does (and none of us has seen the code), then even though it 1) uses less 3 kHz bandwidth, 2) does not appear to do any more harm than a SSB signal and 3) is similar to other FSK modes, it is not legal in FCC jurisdictions. As Bonnie points out, ROS doesn't hop the VFO frequency, but within the 2.5 bandwidth, it technically is SS. This would be true if ROS used 300 Hz bandwidth instead of 2.5 kHz, but hopped about using FHSS within the 300 Hz bandwidth. So I have to agree the FCC regs are not well written in this case. Regarding the corollary issue of US/FCC regulations focused on content instead of bandwidth, I'm not competent to comment. Jim - K6JM - Original Message - *From:*
[digitalradio] 15m
cq/qrv 21.111 usb ROS david/wd4kpd
[digitalradio] Re: Try some JT65A
Steve, Yes, MixW allows these sub-modes as does the excellent free FLDigi program. 73 Sholto --- In digitalradio@yahoogroups.com, Steve n...@... wrote: I keep returning to DM780 as my main digi mode program. It does NOT support Olivia 32/500 or 64/500. I'm running v5.0 beta. I think one of the older releases had an option to set the tones/baud parameters separately. I think MixW will work on these Olivia sub modes. Are these sub modes are slower than the staple 16/500? 73, Steve N6VL --- In digitalradio@yahoogroups.com, sholtofish sholto@ wrote: Andy, Another very sensitive mode to try is Olivia 32/500 or even 64/500. Tony and I managed perfect copy at QRP levels with a very poor path. Bit faster than JT65 too. 73 Sholto
Re: [digitalradio] FCC Technology Jail: ROS Dead on HF for USA Hams
The 300 baud limit applies only to the HF RTTY/data segments. In the phone/image segments below 29 MHz there s no baud rate limit but the bandwidth is limited by the following parts of 97.307(f). (1) No angle-modulated emission may have a modulation index greater than 1 at the highest modulation frequency. (2) No non-phone emission shall exceed the bandwidth of a communications quality phone emission of the same modulation type. The total bandwidth of an independent sideband emission (having B as the first symbol), or a multiplexed image and phone emission, shall not exceed that of a communications quality A3E emission. Given the width of some amateur AM signals on 80 meters, this limit seems to be 10 kHz below 29 MHz. 73, John KD6OZH - Original Message - From: Trevor . To: digitalradio@yahoogroups.com Sent: Monday, February 22, 2010 09:18 UTC Subject: Re: [digitalradio] FCC Technology Jail: ROS Dead on HF for USA Hams However, there may be scope in interpretation of the regs. Up until a few years ago many US amateurs were under the impression that you could only send a maximum of 300 bits per second on HF. What the rules actually specified was a maximum symbol rate of 300 Baud and, probably because no had thought to do so, there was no limit specified on the number of carriers you could transmit. That's how these days US hams can run digital voice/sstv.
Re: [digitalradio] Winlink and Regulation by Bandwidth
Pactor was FSK with a 100% duty cycle (or peak to average power ratio - PAPR), but Pactor-III is OFDM which has a PAPR similar to SSB and much less than SSB with RF clipping so I don't see how its any worse than digital voice or SSTV. Were the two stations in the automated segments fighting or just transferring data in both directions? I just don't see the threat from automated Pactor stations as they are legal on every amateur frequency outside the U.S. and they haven't taken over there. 73, John KD6OZH - Original Message - From: KH6TY To: digitalradio@yahoogroups.com Sent: Monday, February 22, 2010 00:04 UTC Subject: Re: [digitalradio] A closer look at ROS]] John, The principle of regulation by bandwidth that was fostered by Winlink through the ARRL was that any mode would be allowed in a particular segment of bandwidths as long as the bandwidth was the same or similar. No restriction on content or operating methods.This would have meant that the messaging stations would have full access to all of the phone bands with no restrictions. For example, Pactor-III which has about 100% duty cycle (modulation), compared to 30% average for uncompressed phone, could easily displace any phone QSO and the phone operator would not even be able to identify the interfering station because he would not be operating Pactor-III. The result would have been dominance by messaging systems with no place left to have phone QSO's without the possiblity of being interfered with by an automatic messaging station. Messaging stations are run with ARQ so they fear competition of their own kind and you can often see two automatic stations battling automatically for a frequency. As a result they want to spread out over the band as much as possible to avoid interference from each other instead of sharing frequencies on a first-come-first-served basis like everyone else.
Re: [digitalradio] ROS Advantage?
I would have to agree with Andy's observation that the 1 baud mode is as good as using JT65a With the advantage of being able to send more text in one transmission. It is a very slow throughput though. Very 73, Glenn (WB2LMV) From: Howard Brown k...@yahoo.com To: digitalradio@yahoogroups.com Sent: Mon, February 22, 2010 9:55:11 AM Subject: Re: [digitalradio] ROS Advantage? Aside from the legal aspect, does anyone have an opinion as to whether the limited hopping (within the 3khz that it hops) helps the robustness of the waveform? If it makes a tremendous difference, maybe we should all work to get it accepted. Howard K5HB From: J. Moen j...@jwmoen.com To: digitalradio@ yahoogroups. com Sent: Sun, February 21, 2010 9:13:50 PM Subject: Re: [digitalradio] FCC Technology Jail: ROS Dead on HF for USA Hams Bonnie's note describes the US/FCC regulations issues regarding ROS and SS really well. It's the best description of the US problem I've seen on this reflector. After reading what seems like hundreds of notes, I now agree that if ROS uses FHSS techniques, as its author says it does (and none of us has seen the code), then even though it 1) uses less 3 kHz bandwidth, 2) does not appear to do any more harm than a SSB signal and 3) is similar to other FSK modes, it is not legal in FCC jurisdictions. As Bonnie points out, ROS doesn't hop the VFO frequency, but within the 2.5 bandwidth, it technically is SS. This would be true if ROS used 300 Hz bandwidth instead of 2.5 kHz, but hopped about using FHSS within the 300 Hz bandwidth. So I have to agree the FCC regs are not well written in this case. Regarding the corollary issue of US/FCC regulations focused on content instead of bandwidth, I'm not competent to comment. Jim - K6JM - Original Message - From: expeditionradio To: digitalradio@ yahoogroups. com Sent: Sunday, February 21, 2010 5:09 PM Subject: [digitalradio] FCC Technology Jail: ROS Dead on HF for USA Hams Given the fact that ROS Modem has been advertised as Frequency Hopping Spread Spectrum (FHSS), it may be quite difficult for USA amateur radio operators to obtain a positive interpretation of rules by FCC to allow use of ROS on HF without some type of experimental license or waiver. Otherwise, hams will need an amendment of FCC rules to use it in USA. Sadly, this may lead to the early death of ROS among USA hams. If ROS Modem had simply provided the technical specifications of the emission, and not called it Spread Spectrum, there would have been a chance for it to be easily adopted by Ham Radio operators in USA. But, the ROS modem designer is rightfully proud of the design, and he lives in a country that is not bound by FCC rules, and probably had little or no knowledge of how his advertising might prevent thousands of hams from using it in USA. But, as they say, You cannot un-ring a bell, once it has been rung. ROS signal can be viewed as a type of FSK, similar to various other types of n-ary-FSK presently in widespread use by USA hams. The specific algorithms for signal process and format could simply have been documented without calling it Frequency Hopping Spread Spectrum (FHSS). Since it is a narrowband signal (using the FCC and ITU definitions of narrowband emission = less than 3kHz) within the width of an SSB passband, it does not fit the traditional FHSS description as a conventional wideband technique. It probably would not have been viewed as FHSS under the spirit and intention of the FCC rules. It doesn't hop the VFO frequency. It simply FSKs according to a programmable algorithm, and it meets the infamous 1kHz shift 300 baud rule. http://www.arrl. org/FandES/ field/regulation s/news/part97/ d-305.html# 307f3 This is a typical example of how outdated the present FCC rules are, keeping USA hams in TECHNOLOGY JAIL while the rest of the world's hams move forward with digital technology. It should come as no surprise that most of the new ham radio digital modes are not being developed in USA! But, for a moment, let's put aside the issue of current FCC prohibition against Spread Spectrum and/or Frequency Hopping Spread Spectrum, and how it relates to ROS mode. Let's look at bandwidth. There is the other issue of bandwidth that some misguided USA hams have brought up here and in other forums related to ROS. Some superstitious hams seem to erroneously think that there is an over-reaching bandwidth limit in the FCC rules for data/text modes on HF that might indicate what part of the ham band to operate it or not operate it. FACT: There is currently no finite bandwidth limit on HF data/text emission in USA ham bands, except for the sub-band and band edges. FACT: FCC data/text HF rules are still mainly based on content of the emission, not bandwidth. New SDR radios have the potential to transmit and receive wider
[digitalradio] Re: FCC Technology Jail: ROS Dead on HF for USA Hams
Trevor, I sure hope we do not go down that road again! Seems that every time we as a group go ask the FCC to make a definite decision on an issue that is being discussed, we get a forced answer we don't really want to hear, and then we start yet another discussion as to the appropriateness of their decision. A very prominent recent example was the use of amateur radio to train for emergencies by employees of emergency service providers such as hospitals, police, fire departments, etc. What a bag of worms this one stirred up. Or, how about the discussions about the no-code license ramifications. The self proclaimed experts of every field seem to materialize out of nowhere. I am NOT an expert by any stretch of the imagination, but have been on these reflectors long enough to see what generally happens. Let's hope calmer, cooler heads prevail to determine the facts of this new mode, not try to find other thi8ngs to fit them in to make certain points one way or the other. My earlier point was, I do not know how to tell the difference with a receiver as to what a given mode is. In the nature of how SSB works, any modulation could be considered spread spectrum, even voice, if only viewed from the purely emission standpoint. One could even show cause to identify an SSB signal as FM in some viewpoints. Don't misunderstand me, I am not making this proclamation, just indicating there are ways to view it that don't necessarily follow generally accepted definitions of things (sort of like saying FSK, PSK, etc. could be considered SS). I have had this very conversation with folks at the FCC on more than one occasion, and was told they are really only interested in what gets emitted into the ether. I suspect that basic premise has not really changed in the time after Riley left. John KE5HAM --- In digitalradio@yahoogroups.com, Trevor . m5...@... wrote: So it's down to interpretation and it'll hinge on the FCC's formal definition of Spread Spectrum with luck ROS will fall outside of it. Does anybody plan to contact the FCC this morning to get their view ? 73 Trevor M5AKA
Re: [digitalradio] ROS Advantage?
Hi, You must not filter anything in the transceiver. You must pass all bandwith in your receiver because filter are doing by the PC better than you transceiver. De: KH6TY kh...@comcast.net Para: digitalradio@yahoogroups.com Enviado: lun,22 febrero, 2010 18:31 Asunto: Re: [digitalradio] ROS Advantage? Howard, After monitoring 14.101 continuously for two days, I find the following: 1. CW signals (of narrow width, of course) during this past weekend contest often disrupted decoding, and it looks like it was not desensitization due to AGC capture, as the ROS signals on the waterfall did not appear any weaker. 2. Pactor signals of 500 Hz width, outside the ROS signal, that capture the AGC, do desensitize the receiver and cause loss of decoding, as expected. Passband tuning takes care of that problem however. 3. Pactor signals which have the same degree of darkness as the ROS carriers, and occur within the upper third of the ROS signal, cause loss of decoding, and it is not possible to fix the problem with passband tuning, as trying to do that appears to take away enough of the ROS signal that the degree of frequency hopping used is insufficient to overcome. Receiver is the IC-746Pro. 4. If more than one ROS signal is present on the frequency, ROS will decode one of them - apparently the strongest one - and the weaker one is blanked out until the stronger one goes away and the the weaker one is decoded. 5. Compared to Olivia 16-500, for example, the width of the ROS signal seems to be a disadvantage as far as handling QRM is concerned. Five Olivia 16-500 signals will fit in the same space as one ROS signal needs, so QRM, covering the top 40% of the ROS signal, for example, would probably not disrupt any of three Olivia signals in the bottom 60% of the ROS signal bandwidth. In other words, the wide bandwidth required for ROS to work is a disadvantage because IF filtering cannot remove narrower band QRM signals that fall within the area of the ROS signal, but IF filtering can remove the same QRM from the passband that has been narrowed to accept only an Olivia signal. A much wider expansion or spectrum spread might reduce the probability of decoding disruption, but that also makes the signal wider still and more susceptible to additional QRM. The advantage of FHSS appears to be more in favor of making it hard to copy a traditional SS signal unless the code is available, than QRM survival, but on crowded ham bands, it looks like a sensitive mode like Olivia or MFSK16, because it is more narrow, and filters can be tighter, stands a better chance of surviving QRM than the ROS signal which is exposed to more possibilities of QRM due to its comparatively greater width. The mode sure is fun to use and it is too bad it does not appear to be as QRM resistant as hoped, at least according to my observations. Another problem is finding a frequency space wide enough to accommodate several ROS signals at once so there is no cross-interference. It is much easier to find space for five Olivia or MFSK16 signals than for even two ROS signals. These are only my personal observations and opinions. Others may find differently. I still plan to find out if ROS can withstand the extreme Doppler shift and flutter on UHF which just tears up even moderately strong SSB phone signals. Olivia appears to be the best alternative mode to SSB phone we have found so far and sometimes provides slightly better copy than SSB phone, but for very weak signals, CW still works the best. Even though the note is very rough sounding, as in Aurora communications, CW can still be copied by ear as it modulates the background noise. 73 - Skip KH6TY Howard Brown wrote: Aside from the legal aspect, does anyone have an opinion as to whether the limited hopping (within the 3khz that it hops) helps the robustness of the waveform? If it makes a tremendous difference, maybe we should all work to get it accepted. Howard K5HB From: J. Moen j...@jwmoen.com To: digitalradio@ yahoogroups. com Sent: Sun, February 21, 2010 9:13:50 PM Subject: Re: [digitalradio] FCC Technology Jail: ROS Dead on HF for USA Hams Bonnie's note describes the US/FCC regulations issues regarding ROS and SS really well. It's the best description of the US problem I've seen on this reflector. After reading what seems like hundreds of notes, I now agree that if ROS uses FHSS techniques, as its author says it does (and none of us has seen the code), then even though it 1) uses less 3 kHz bandwidth, 2) does not appear to do any more harm than a SSB signal and 3) is similar to other FSK modes, it is not legal in FCC jurisdictions. As Bonnie points out, ROS doesn't hop the VFO frequency, but within the 2.5 bandwidth, it technically is SS. This would be true if ROS used 300 Hz bandwidth instead of 2.5 kHz, but hopped about using FHSS within the
Re: [digitalradio] ROS Advantage?
KH6TY wrote: 2. Pactor signals of 500 Hz width, outside the ROS signal, that capture the AGC, do desensitize the receiver and cause loss of decoding, as expected. Passband tuning takes care of that problem however. As with many other digital modes, I've been using it with AGC switched off. Dave (G0DJA)
Re: [digitalradio] ROS - make it legal in USA
Dave wrote: The closest you get to a true definition in Part 97 is in section 97.3 Definitions, Para C, line 8: /(8) SS/. Spread-spectrum emissions using bandwidth-expansion modulation emissions having designators with A, C, D, F, G, H, J or R as the first symbol; X as the second symbol; X as the third symbol. I disagree, that's not a definition of Spread Spectrum, it's a restriction on spread spectrum. And not a very useful one, as in it's not specific enough to entirely limit the (presumably) bad SS, and yet it may disallow modes which are not the target. All due to poor wording. You have to define bandwidth expansion. I'm rusty, but it's normally when the impacted bandwidth (think footprint) used exceeds the information bandwidth. Which itself is usually something less than the Shannon limit. What they are really saying is bandwidth expansion *factor* greater than one, and for nearly all traditional spread spectrum (Frequency Hopping direct sequence) that is a factor of 20 to 250 or more. We could argue whether mode X is legal or not, but if you are going to be legalistic, then modulated CW is illegal as well as it's bandwidth is greater than the information bandwidth. (bandwidth expansion 1) And even regular CW, PSK, and others when the gear is not operated correctly. Bandwidth information bandwidth is a harsh measure! Even some SSB voice stations could be at risk! :-) Realistically, many modems use spread spectrum type approaches to spread randomize the energy inside the typical voice/SSB bandwidth. The FCC cares about bandwidth. We know from the symbol rate rulings that they are not inclined to deal with overly strict legal interpretation on wording. The symbol rate restriction is used as a (bad) analog for bandwidth, as it's what was used when the regs were made. So the same type arguments surfaced around symbol rate (real vs theoretical, etc). And we know from all the Pactor 3 on the air how that ended up! So at the risk of being an armchair lawyer as well, I do think you have to apply some rule of reason. What's the intent of the restriction? To not allow direct or random sequence spread spectrum on the lower bands. Largely defined by DS-CDMA FS-CDMA approaches used as the classical spread spectrum modes. This is what the military uses, what the VHF/UHF devices use, etc. And they have much larger footprints (bandwidth expansion of 20 or more), so should not be allowed on HF. Really what we are talking about is an afsk'ish soundcard mode that stays in one SSB bandwidth slot or less. Is it classical spread spectrum? Clearly not. Is it technically spread spectrum? Would depend on exact semantic definitions. But since the implied dial/carrier frequency does not move, is detectable without extreme measures, and is not going to effectively raise the noise floor of the entire HF band, I would be very surprised to see the FCC wade in and say it's spread spectrum. ROS uses SSB so the first designator is J (this meets the definition) and it uses bandwidth-expansion. (this meets that definition as well) Thus, taking this definition literally, it is indeed Spread Spectrum and is thus illegal below 222MHzat least that the conservative interpretation that I'll stick with until we get a ruling otherwise. So using your literal test, modulated CW is not legal, as it's J and has bandwidth expansion factor 1 in the real world. You could question several AFSK modes as typically used by hams. (artifacts and all). Each time we go to the FCC for things like this it's like small children going to the teacher and asking is this allowed?. There is a certain amount of impatience, and based on past discussions/interpretations the FCC will lean toward common sense interpretations. Largely defined by bandwidth, crypto definitions and not obscure technical definitions. Ideally, we'd have a reasonable approach to using our spectrum. I think there is 2-3 options in use in other countries we could adopt that would simplify this type issue and result in no net loss for current legacy modes. Yet they always dies with FUD from the broader community without being debated on their merits. There is no option to rationally discuss, it's all or nothing. So we get to pay the price with digital definitions based on 30's (or older) technology. Just about all the modes which achieve good weak signal performance do so by trading off effective throughput for bandwidth. Some are more efficient than others in this regard. Do I think the FCC cares about another soundcard mode that lives politely in a single SSB width signal? Nope, as long as it's not encrypted. But that's just my read. I'm sure we'll have many others! :-) Have fun, Alan km4ba
Re: [digitalradio] ROS Advantage?
Hi Jose, Of course we start that way (using a SSB filter), but then a Pactor station will come on, cover the upper fourth of the ROS signal, and decoding becomes garbage until it leaves. With a more narrow mode, the Pactor station can just be filtered out at IF frequencies and not affect either the AGC or the decoding of something like MFSK16 or Olivia 16-500, as long as those signals are sufficiently away from the Pactor signal (even if they are still within the bandwidth of a ROS signal). In the case of CW stations, during the contest, they just appeared in the SSB filter bandwidth, and therefore among the ROS tones, and some of those also stopped decoding until they left. Let's say a MT63-500 signal appears at 2000 Hz tone frequency (i.e. covering from 2000 to 2500 Hz) at the same signal strength as the ROS signal. Will ROS stop decoding? If a MT-63-1000 signal appears at 1500 Hz tone frequency, will ROS stop decoding? If this happens and there is a more narrowband signal like MFSK16, for instance, covering from 500 Hz to 1000 Hz, the MFSK16 signal can coexist with the MT63 signal unless the MT63 signal has captured the AGC and cutting the gain. If it has, then passband tuning can cut out the MT63 signal, leaving only the MFSK16 signal undisturbed and decoding. In other words, there is less chance for an interfering signal to partially or completely cover a more narrow signal that there is a much wider one, unless the wider one can still decode with half or 25% of its tones covered up. The question posed is how well ROS can handle QRM, and that is what I tried to see. If ROS can withstand half of its bandwidth covered with an interfering signal and still decode properly then I cannot explain what I saw, but decoding definitely stopped or changed to garbage when the Pactor signal came on. 73 - Skip KH6TY jose alberto nieto ros wrote: Hi, You must not filter anything in the transceiver. You must pass all bandwith in your receiver because filter are doing by the PC better than you transceiver. *De:* KH6TY kh...@comcast.net *Para:* digitalradio@yahoogroups.com *Enviado:* lun,22 febrero, 2010 18:31 *Asunto:* Re: [digitalradio] ROS Advantage? Howard, After monitoring 14.101 continuously for two days, I find the following: 1. CW signals (of narrow width, of course) during this past weekend contest often disrupted decoding, and it looks like it was not desensitization due to AGC capture, as the ROS signals on the waterfall did not appear any weaker. 2. Pactor signals of 500 Hz width, outside the ROS signal, that capture the AGC, do desensitize the receiver and cause loss of decoding, as expected. Passband tuning takes care of that problem however. 3. Pactor signals which have the same degree of darkness as the ROS carriers, and occur within the upper third of the ROS signal, cause loss of decoding, and it is not possible to fix the problem with passband tuning, as trying to do that appears to take away enough of the ROS signal that the degree of frequency hopping used is insufficient to overcome. Receiver is the IC-746Pro. 4. If more than one ROS signal is present on the frequency, ROS will decode one of them - apparently the strongest one - and the weaker one is blanked out until the stronger one goes away and the the weaker one is decoded. 5. Compared to Olivia 16-500, for example, the width of the ROS signal seems to be a disadvantage as far as handling QRM is concerned. Five Olivia 16-500 signals will fit in the same space as one ROS signal needs, so QRM, covering the top 40% of the ROS signal, for example, would probably not disrupt any of three Olivia signals in the bottom 60% of the ROS signal bandwidth. In other words, the wide bandwidth required for ROS to work is a disadvantage because IF filtering cannot remove narrower band QRM signals that fall within the area of the ROS signal, but IF filtering can remove the same QRM from the passband that has been narrowed to accept only an Olivia signal. A much wider expansion or spectrum spread might reduce the probability of decoding disruption, but that also makes the signal wider still and more susceptible to additional QRM. The advantage of FHSS appears to be more in favor of making it hard to copy a traditional SS signal unless the code is available, than QRM survival, but on crowded ham bands, it looks like a sensitive mode like Olivia or MFSK16, because it is more narrow, and filters can be tighter, stands a better chance of surviving QRM than the ROS signal which is exposed to more possibilities of QRM due to its comparatively greater width. The mode sure is fun to use and it is too bad it does not appear to be as QRM resistant as hoped, at least according to my observations. Another problem is finding a frequency space wide enough to accommodate several ROS signals at once so
Re: [digitalradio] ROS Advantage?
That is good, Dave, except for receivers that distort heavily when the AGC is disabled. If you just use manual gain control, and reduce the gain for strong signals, the effect is the same, only manual. You will lose the weak station because you have reduced the gain and the sensitivity. The only way to still copy your weak station and get rid of the strong one is to filter at IF frequencies, which is what fixed filters or passband tuning does. IF DSP will do it also these days, but it needs to be at IF frequencies and not audio frequencies if you are going to prevent AGC capture by an unwanted stronger signal. 14.101 is adjacent to Pactor activity and if you monitor it long enough, you will see the Pactor station stop decoding of ROS. However, most of the automatic Pactor activity we hear is in the US, so the problem may not be as big on the other side of the big pond. 73 - Skip KH6TY Dave Ackrill wrote: KH6TY wrote: 2. Pactor signals of 500 Hz width, outside the ROS signal, that capture the AGC, do desensitize the receiver and cause loss of decoding, as expected. Passband tuning takes care of that problem however. As with many other digital modes, I've been using it with AGC switched off. Dave (G0DJA)
Re: [digitalradio] FCC Technology Jail: ROS Dead on HF for USA Hams
I am not going to wade back into part 97 for this, but I believe 5 khz audio is beyond the scope of being communications quality. I know a number people who have a lot of rebuilt broadcast audio gear and are also audiophiles, many in the pro audio business and they are really in to this. Regardless, more than 3 khz if not blatantly illegal is certainly not what the FCC intended. From: John B. Stephensen kd6...@comcast.net Reply-To: digitalradio@yahoogroups.com Date: Mon, 22 Feb 2010 20:27:41 - To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] FCC Technology Jail: ROS Dead on HF for USA Hams The 300 baud limit applies only to the HF RTTY/data segments. In the phone/image segments below 29 MHz there s no baud rate limit but the bandwidth is limited by the following parts of 97.307(f). (1) No angle-modulated emission may have a modulation index greater than 1 at the highest modulation frequency. (2) No non-phone emission shall exceed the bandwidth of a communications quality phone emission of the same modulation type. The total bandwidth of an independent sideband emission (having B as the first symbol), or a multiplexed image and phone emission, shall not exceed that of a communications quality A3E emission. Given the width of some amateur AM signals on 80 meters, this limit seems to be 10 kHz below 29 MHz. 73, John KD6OZH - Original Message - From: Trevor . mailto:m5...@yahoo.co.uk To: digitalradio@yahoogroups.com Sent: Monday, February 22, 2010 09:18 UTC Subject: Re: [digitalradio] FCC Technology Jail: ROS Dead on HF for USA Hams However, there may be scope in interpretation of the regs. Up until a few years ago many US amateurs were under the impression that you could only send a maximum of 300 bits per second on HF. What the rules actually specified was a maximum symbol rate of 300 Baud and, probably because no had thought to do so, there was no limit specified on the number of carriers you could transmit. That's how these days US hams can run digital voice/sstv.
Re: [digitalradio] ROS Advantage?
Please, give a frequency alternative to 14.101 De: KH6TY kh...@comcast.net Para: digitalradio@yahoogroups.com Enviado: lun,22 febrero, 2010 22:39 Asunto: Re: [digitalradio] ROS Advantage? That is good, Dave, except for receivers that distort heavily when the AGC is disabled. If you just use manual gain control, and reduce the gain for strong signals, the effect is the same, only manual. You will lose the weak station because you have reduced the gain and the sensitivity. The only way to still copy your weak station and get rid of the strong one is to filter at IF frequencies, which is what fixed filters or passband tuning does. IF DSP will do it also these days, but it needs to be at IF frequencies and not audio frequencies if you are going to prevent AGC capture by an unwanted stronger signal. 14.101 is adjacent to Pactor activity and if you monitor it long enough, you will see the Pactor station stop decoding of ROS. However, most of the automatic Pactor activity we hear is in the US, so the problem may not be as big on the other side of the big pond. 73 - Skip KH6TY Dave Ackrill wrote: KH6TY wrote: 2. Pactor signals of 500 Hz width, outside the ROS signal, that capture the AGC, do desensitize the receiver and cause loss of decoding, as expected. Passband tuning takes care of that problem however. As with many other digital modes, I've been using it with AGC switched off. Dave (G0DJA)
Re: [digitalradio] ROS Advantage?
Glenn L. Roeser wrote: I would have to agree with Andy's observation that the 1 baud mode is as good as using JT65a With the advantage of being able to send more text in one transmission. It is a very slow throughput though. Very 73, Glenn (WB2LMV) You have to be the patient sort, maybe a WSPR QSO fan, to use ROS 1 baud. It does, however, allow you to nip down, get a pint and get back before the other person has finished calling CQ though. :-) Yet to receive an email confirmation for 1 baud as yet. Has anyone received one from me for 1 baud yet? I've see full email addresses for at least one station, IW1GJJ, tonight. Dave (G0DJA)
[digitalradio] Has anyone tried this?
Came across this the other day: http://db0lj.prgm.org/boxfiles/software/Gtor.zip Looks like it's a sound card implementation of G-TOR?? Seems to have a butterfly icon so something to do with MixW?? Does it work?
Re: [digitalradio] ROS Advantage?
Jose, I will be using 432.090 MHz because that is definitely legal for US hams. I will be testing the effect of severe Doppler-induced fading and flutter. We badly need a mode for 432 MHz that has good sensitivity and can survive fast Doppler shifts, and I hope a FHSS mode like ROS is going to do it. Will have a result around the last week of next month. The hflink published ALE frequencies might be a good alternative for others around the world, since ALE users should not notice the FHSS ROS activity (according to the ROS documentation) and their soundings are infrequent and of short duration, so they should cause minimal interference to ROS activities. They are also already in the area for wide bandwidth signals, I think. On 20m, those frequencies appear to be 14100.5, 14109.0, and 14.112.0. See http://hflink.com/channels/. Keep in mind there are NO frequencies completely free of QRM except on VHF and UHF, but some can be found on HF that have less opportunity for interference than others, so the ALE frequencies might be a good place to try. Of course, ALE users MUST, by US law, be sure the frequency is clear before transmitting, and the same applies to ROS users. We all have to share frequencies, since no frequencies are owned by anyone, but are used on a first-come, first-served basis. 73 - Skip KH6TY jose alberto nieto ros wrote: Please, give a frequency alternative to 14.101 *De:* KH6TY kh...@comcast.net *Para:* digitalradio@yahoogroups.com *Enviado:* lun,22 febrero, 2010 22:39 *Asunto:* Re: [digitalradio] ROS Advantage? That is good, Dave, except for receivers that distort heavily when the AGC is disabled. If you just use manual gain control, and reduce the gain for strong signals, the effect is the same, only manual. You will lose the weak station because you have reduced the gain and the sensitivity. The only way to still copy your weak station and get rid of the strong one is to filter at IF frequencies, which is what fixed filters or passband tuning does. IF DSP will do it also these days, but it needs to be at IF frequencies and not audio frequencies if you are going to prevent AGC capture by an unwanted stronger signal. 14.101 is adjacent to Pactor activity and if you monitor it long enough, you will see the Pactor station stop decoding of ROS. However, most of the automatic Pactor activity we hear is in the US, so the problem may not be as big on the other side of the big pond. 73 - Skip KH6TY Dave Ackrill wrote: KH6TY wrote: 2. Pactor signals of 500 Hz width, outside the ROS signal, that capture the AGC, do desensitize the receiver and cause loss of decoding, as expected. Passband tuning takes care of that problem however. As with many other digital modes, I've been using it with AGC switched off. Dave (G0DJA)
[digitalradio] ROS...suggested QRG on 20M.
I would suggest 14109. Anything from 14101 to 14112 should work but Winmor is often at 14112. PACTOR is everywhere in this range but that is just the way the band can be. 14101 has been good most of the day but 14102 is a common frequency for Olivia, see below. +8h EA3AQS Spain14102.41OLIVIA DL7JP +8h OH/DK4ZC Finland14102.52OLIVIA DL7JP +8h EU6PW Belarus 10141.97MFSK16 G0UZP +8h DM2AUO Germany 14103.28OLIVIA DL7JP +8h DM2AUO Germany 14103.27OLIVIA DL7JP +8h DM2DTH Germany 14102.25OLIVIA DL7JP +8h IK4G Italy 14102.52OLIVIA DL7JP +8h IK4GBU Italy14102.51OLIVIA DL7JP +8h OH2HN Finland 14102.49OLIVIA DL7JP and 14101 is common for packet, I think. When I do a search for DX spots oon the frequency range 14101 to 14112 , 14101-14103 come out the busiest . 14104 to 14112 have very little posted activity. ALE and Olivia can be on 14109 but activity is light, and brief. 14101 was crowded for ROS 16 today , but it seems that using 14104 to 14112 would be a good choice for most activity . There may be QRM from RTTY during contests. Andy K3UK PE1AUV 14100.0 RA6FCU olivia 32/1000 tnx 1744 22 Feb European Russia EA8BJM 14106.0 EA8ATE OLIVIA 32/1000 SERGIO 1857 21 Feb Canary Islands F4BMY-@14144.0 WA1VMG tnx fer qso olivia 1830 21 Feb United States EA8BJM 14106.0 EA8BJM OLIVIA 32/1000 SERGIO 1730 20 Feb Canary Islands HB9BTI-@ 14105.0 HB9GTCQ Olivia 1453 20 Feb Switzerland TF3AO 14107.0 EA8ATE OLIVIA CQ 0959 20 Feb Canary Islands EA8BJM 14106.0 EA8ATE OLIVIA 32/1000 SERGIO 0954 20 Feb Canary Islands OZ1PMX-@ 14105.0 IK4GBU OLIVIA vy wide signal 0728 15 Feb Italy UU4JII-@ 14106.5 UU4JOOLIVIA 1000/32 CQ 0945 12 Feb Ukraine UU4JII-@ 14106.5 UU4JOOLIVIA 1000/32 CQ 0939 12 Feb Ukraine RK 9A3JB 14105.5 9A0HRS cq olivia 2147 09 Feb Croatia UN7TK-@14107.5 UN7TKOLIVIA Cq CQ Cq 0648 09 Feb Kazakhstan IV3DAI-@ 14106.0 UU4JOOLIVIA MODE1235 08 Feb Ukraine UU0AK-@14106.5 UU4JOOLIVIA MODE 1000/321217 08 Feb Ukraine UU8JC-@14106.5 UU4JOMODE OLIVIA 1000/321437 07 Feb Ukraine UU8JC-@14106.5 UU4JOOLIVIA 1000/32 599 1336 06 Feb Ukraine UA1CSB-@ 14106.5 UU4JOOLIVIA 1000/32 599 NICE SIGNAL CQ 1320 06 Feb Ukraine UU4JII-@ 14106.5 UU4JOOLIVIA 1000/32 1313 06 Feb Ukraine EA1EYG 14099.9 TI8IITU Carlos OLIVIA 731703 05 Feb Costa Rica 9H1EI 14099.4 9H1LOTESTING OLIVIA 1655 05 Feb Malta VE1GW 14106.2 UA6CEOlivia 16/500 Tnx Vlad!!! 1405 04 Feb European Russia PE1AUV 14107.7 UA6CEolivia 32/1000 tnx 1345 04 Feb European Russia 16/500 2352 30 Jan Japan 8/250 1723 24 Jan United States ON3VHF 14105.0 KZ6ZZolivia tks qso Jack1723 20 Jan United States ON3VHF 14105.0 KB1EZW olivia tks qso mike1659 20 Jan United States ON3VHF 14105.0 AA4FSolivia tks qso Frank call vhf 1633 20 Jan United States DD8HB-@14106.0 ON3VHF OLIVIA 1604 20 Jan Belgium YO4BTB-@ 14106.5 OH2BNOLIVIA 0919 15 Jan Finland UN7TK-@14107.5 TEST OLIVIA 2205 12 Jan Not Found UA0ZEO-@ 14072.6 VE7NBQ OLIVIA PETER VANCOUVER 2346 11 Jan Canada A61BN-@14107.0 A61BKOLIVIA SPECIAL CARD BURJ KHALIFA 1256 11 Jan United Arab Emir SWL-@ 14108.5 RN3DVOLIVIA 32/1000 u r 599 in OE6 0937 10 Jan European Russia UA9OEX-@ 14105.6 UA9OEX OLIVIA via buro or direct Igor Asi 1033 09 Jan Asiatic Russia UA9OEX 14105.6 UA9OEX OLIVIA via buro or direct Igor 0833 09 Jan Asiatic Russia G1OCN 14108.3 VE2AHS OLIVIA CQ 1031 07 Jan Canada UN7TK-@14107.5 UN7TKOLIVIA Cq DX Cq1236 05 Jan Kazakhstan UN7TK 14107.5 UN7TKOLIVIA Cq DX Cq1036 05 Jan Kazakhstan DC6MY
[digitalradio] GTOR- has anyone tried this?
Interesting. The about info reveals Mixw 2003. I also found this G-TOR (Golay -TOR) is an FSK mode that offers a fast transfer rate compared to Pactor. It incorporates a data inter-leaving system that assists in minimizing the effects of atmospheric noise and has the ability to fix garbled data. G-tor tries to perform all transmissions at 300 baud but drops to 200 baud if difficulties are encountered and finally to 100 baud. (The protocol that brought back those good photos of Saturn and Jupiter from the Voyager space shots was devised by M.Golay and now adapted for ham radio use.) G-tor is found in only one manufacture's TNC and is rarely used today. --- In digitalradio@yahoogroups.com, sholtofish sho...@... wrote: Came across this the other day: http://db0lj.prgm.org/boxfiles/software/Gtor.zip Looks like it's a sound card implementation of G-TOR?? Seems to have a butterfly icon so something to do with MixW?? Does it work?
Re: [digitalradio] ROS Advantage?
That is true, narrow band interference cause a minimal interference to ROS, and at the same form, ROS cause minimal interference to narrow band modes. The problem is if you join two wide modes at the same frequency. De: KH6TY kh...@comcast.net Para: digitalradio@yahoogroups.com Enviado: lun,22 febrero, 2010 23:23 Asunto: Re: [digitalradio] ROS Advantage? The hflink published ALE frequencies might be a good alternative for others around the world, since ALE users should not notice the FHSS ROS activity (according to the ROS documentation) and their soundings are infrequent and of short duration, so they should cause minimal interference to ROS activities.
[digitalradio] Re: GTOR- has anyone tried this?
It works , Sholto. I am able to get PTT working and generate tones. Anyone for G-Tor? Andy K3UK --- In digitalradio@yahoogroups.com, obrienaj k3uka...@... wrote: Interesting. The about info reveals Mixw 2003. I also found this G-TOR (Golay -TOR) is an FSK mode that offers a fast transfer rate compared to Pactor. It incorporates a data inter-leaving system that assists in minimizing the effects of atmospheric noise and has the ability to fix garbled data. G-tor tries to perform all transmissions at 300 baud but drops to 200 baud if difficulties are encountered and finally to 100 baud. (The protocol that brought back those good photos of Saturn and Jupiter from the Voyager space shots was devised by M.Golay and now adapted for ham radio use.) G-tor is found in only one manufacture's TNC and is rarely used today. --- In digitalradio@yahoogroups.com, sholtofish sholto@ wrote: Came across this the other day: http://db0lj.prgm.org/boxfiles/software/Gtor.zip Looks like it's a sound card implementation of G-TOR?? Seems to have a butterfly icon so something to do with MixW?? Does it work?
Re: [digitalradio] ROS Advantage?
I agree with Andy - try 14.109 USB next. ALE is wideband, but of short duration. It is worth a try, I think. 73 - Skip KH6TY jose alberto nieto ros wrote: That is true, narrow band interference cause a minimal interference to ROS, and at the same form, ROS cause minimal interference to narrow band modes. The problem is if you join two wide modes at the same frequency. *De:* KH6TY kh...@comcast.net *Para:* digitalradio@yahoogroups.com *Enviado:* lun,22 febrero, 2010 23:23 *Asunto:* Re: [digitalradio] ROS Advantage? The hflink published ALE frequencies might be a good alternative for others around the world, since ALE users should not notice the FHSS ROS activity (according to the ROS documentation) and their soundings are infrequent and of short duration, so they should cause minimal interference to ROS activities.
[digitalradio] Re: GTOR- has anyone tried this?
Hi Andy, I have a real G-TOR modem here so will test with you. A traditional frequency is 14.111 (center frequency). The tones in my KAM are 1400/1600 so my dial (in LSB) reads 14.112.5 Though G-TOR is polarity independent. 73 K7TMG --- In digitalradio@yahoogroups.com, obrienaj k3uka...@... wrote: It works , Sholto. I am able to get PTT working and generate tones. Anyone for G-Tor? Andy K3UK --- In digitalradio@yahoogroups.com, obrienaj k3ukandy@ wrote: Interesting. The about info reveals Mixw 2003. I also found this G-TOR (Golay -TOR) is an FSK mode that offers a fast transfer rate compared to Pactor. It incorporates a data inter-leaving system that assists in minimizing the effects of atmospheric noise and has the ability to fix garbled data. G-tor tries to perform all transmissions at 300 baud but drops to 200 baud if difficulties are encountered and finally to 100 baud. (The protocol that brought back those good photos of Saturn and Jupiter from the Voyager space shots was devised by M.Golay and now adapted for ham radio use.) G-tor is found in only one manufacture's TNC and is rarely used today. --- In digitalradio@yahoogroups.com, sholtofish sholto@ wrote: Came across this the other day: http://db0lj.prgm.org/boxfiles/software/Gtor.zip Looks like it's a sound card implementation of G-TOR?? Seems to have a butterfly icon so something to do with MixW?? Does it work?
Re: [digitalradio] ROS Advantage?
KH6TY wrote: Jose, I will be using 432.090 MHz because that is definitely legal for US hams. I will be testing the effect of severe Doppler-induced fading and flutter. We badly need a mode for 432 MHz that has good sensitivity and can survive fast Doppler shifts, and I hope a FHSS mode like ROS is going to do it. Will have a result around the last week of next month. I'd be interested in those results as I hope to fix a problem on my 1296MHz antenna soon, and aircraft reflection (Doppler) is definitely a problem on many other data modes on 23cm. Now, if we could crack extreme doppler, like Aurora on VHF or rain/hail/snow scatter on 10 and 24GHz, that would be a real step forward... Dave (G0DJA)
Re: [digitalradio] ROS Advantage- mode ranking
It seems unfair, especially because of all the hard work put in to developing it, but I do not see it as any better than many other modes... nothing that says gee...this is way better . It is GOOD, and a mode to add to our bag of tricks, but not a killer app. The software interface is very nicely done, Jose should be congratulated on this. I'll place a few modes in a robustness category for us all. SUPER WEAK MODES JT65A (and family) WSPR ROS 1 Jason WEAK MODES Olivia 1000/32 ALE400 Domino MFSK16/8 Pactor III MT63 ROS 16 PSK10 PSKAM10 Contesia 500/12 DominoEX 4 FEC31 THROBx4 THOR 11 AVERAGE PSK31 PSK63 PACTOR II /I Hell RTTYM Contestia 50016 Chip 64/128 Olvia 8/500 Strong signal required RTTY PSK125-500 Standard ALE Packet 300 baud WINMOR
[digitalradio] Curious sound card modes question -
So as to not continue growing the ROS legality discussion even further, I would like to ask a fairly simple question. How will the modulation be determined from any SSB transmitter when the source of the modulation is via the microphone audio input of that transmitter? Simply stated, how would any digital mode create anything other than some form of FSK simply by inputting a tone at the microphone input? Regardless of the software being used to generate the tone(s), at any given time there is nothing more than the absence or presence of a tone at the audio input of the transmitter. This is true of HRD's DM780, MixW modes, MMSSTV, or many other sound card driven software packages. They all have one thing in common, they generate a sequence of tones which is then processed by the very same transmitter in the very same way. The maximum output bandwidth is supposed to be somewhat limited in the bandpass of the transmitter circuitry (which is NOT being altered). Again, NO transmitter circuitry is being altered in any way that I am aware of. With this discussion, how do we arbitrarily change the transmitter output definitions? I am truly asking because that is a concept beyond my feeble mind. I really do not know. To me, regardless of the source of the modulation itself, the modulation still remains an offset of the carrier frequency by the frequency of the input tone. To me, the discussion of particular FCC designators for any of these modes is rather moot, unless there is some method to tie the two together. To simply start an argument about a particular FCC rule, without showing the correlation to the subject is somewhat like arguing the color of orange peels in an apple pie instruction sheet. They simply don't necessarily relate. Both may have valid points about their own arguments, but the tow simply do not go together. Am I missing something besides a few marbles now? My head is spinning from all these rules being bandied about, that may have no application here at all. John KE5HAM
Re: [digitalradio] ROS Advantage- mode ranking
Andy obrien wrote: It seems unfair, especially because of all the hard work put in to developing it, but I do not see it as any better than many other modes... nothing that says gee...this is way better . It is GOOD, and a mode to add to our bag of tricks, but not a killer app. The software interface is very nicely done, Jose should be congratulated on this. I'll place a few modes in a robustness category for us all. I'm not sure things tend to boil down that way, to be honest Andy, Otherwise why so much RTTY on the bands? Even AX:25 is getting a bit long in the tooth now, but people still struggle on with it... Dave (G0DJA)
Re: [digitalradio] ROS Advantage?
One thing, 14.109 means that first tone is on 14.109.4 and last tone is on 14.111.65 According to that, wich would the best option? De: KH6TY kh...@comcast.net Para: digitalradio@yahoogroups.com Enviado: lun,22 febrero, 2010 23:46 Asunto: Re: [digitalradio] ROS Advantage? I agree with Andy - try 14.109 USB next. ALE is wideband, but of short duration. It is worth a try, I think. 73 - Skip KH6TY jose alberto nieto ros wrote: That is true, narrow band interference cause a minimal interference to ROS, and at the same form, ROS cause minimal interference to narrow band modes. The problem is if you join two wide modes at the same frequency. De: KH6TY kh...@comcast. net Para: digitalradio@ yahoogroups. com Enviado: lun,22 febrero, 2010 23:23 Asunto: Re: [digitalradio] ROS Advantage? The hflink published ALE frequencies might be a good alternative for others around the world, since ALE users should not notice the FHSS ROS activity (according to the ROS documentation) and their soundings are infrequent and of short duration, so they should cause minimal interference to ROS activities.
RE: [digitalradio] Winlink and Regulation by Bandwidth
The issue is not the protocol, but rather automatic operation without a busy frequency detector. An operator invokes a remote automatic station, whose subsequent transmissions QRM an ongoing QSO that the operator doesn't hear (but would hear clearly if he or she were monitoring the remote station's receiver). Participants in the ongoing QSO have no way convey QRL to the automatic station. 73, Dave, AA6YQ -Original Message- From: digitalradio@yahoogroups.com [mailto:digitalra...@yahoogroups.com]on Behalf Of John B. Stephensen Sent: Monday, February 22, 2010 3:47 PM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Winlink and Regulation by Bandwidth Pactor was FSK with a 100% duty cycle (or peak to average power ratio - PAPR), but Pactor-III is OFDM which has a PAPR similar to SSB and much less than SSB with RF clipping so I don't see how its any worse than digital voice or SSTV. Were the two stations in the automated segments fighting or just transferring data in both directions? I just don't see the threat from automated Pactor stations as they are legal on every amateur frequency outside the U.S. and they haven't taken over there. 73, John KD6OZH - Original Message - From: KH6TY To: digitalradio@yahoogroups.com Sent: Monday, February 22, 2010 00:04 UTC Subject: Re: [digitalradio] A closer look at ROS]] John, The principle of regulation by bandwidth that was fostered by Winlink through the ARRL was that any mode would be allowed in a particular segment of bandwidths as long as the bandwidth was the same or similar. No restriction on content or operating methods.This would have meant that the messaging stations would have full access to all of the phone bands with no restrictions. For example, Pactor-III which has about 100% duty cycle (modulation), compared to 30% average for uncompressed phone, could easily displace any phone QSO and the phone operator would not even be able to identify the interfering station because he would not be operating Pactor-III. The result would have been dominance by messaging systems with no place left to have phone QSO's without the possiblity of being interfered with by an automatic messaging station. Messaging stations are run with ARQ so they fear competition of their own kind and you can often see two automatic stations battling automatically for a frequency. As a result they want to spread out over the band as much as possible to avoid interference from each other instead of sharing frequencies on a first-come-first-served basis like everyone else.
Re: [digitalradio] Re: GTOR- has anyone tried this?
sholtofish wrote: Hi Andy, I have a real G-TOR modem here so will test with you. I remember a friend of mine, back in the mid-1980s I think, running AMTOR. He graduated from RTTY and ran something like an FT-101ZD with a dual beam scope showing when the two tone signals were correctly spaced. I guess RTTY goes back even further though. Then Packet (AX:25) came on the scene and I went for that instead. Although I did own a KAM+ at one time, I never did get the hang of the TOR modes. Dave (G0DJA)
Re: [digitalradio] ROS Advantage?
Andy, you have used ALE. What center frequency or suppressed carrier frequency should be used to be on the ALE channel at 14.109? 73 - Skip KH6TY jose alberto nieto ros wrote: One thing, 14.109 means that first tone is on 14.109.4 and last tone is on 14.111.65 According to that, wich would the best option? *De:* KH6TY kh...@comcast.net *Para:* digitalradio@yahoogroups.com *Enviado:* lun,22 febrero, 2010 23:46 *Asunto:* Re: [digitalradio] ROS Advantage? I agree with Andy - try 14.109 USB next. ALE is wideband, but of short duration. It is worth a try, I think. 73 - Skip KH6TY jose alberto nieto ros wrote: That is true, narrow band interference cause a minimal interference to ROS, and at the same form, ROS cause minimal interference to narrow band modes. The problem is if you join two wide modes at the same frequency. *De:* KH6TY kh...@comcast. net *Para:* digitalradio@ yahoogroups. com *Enviado:* lun,22 febrero, 2010 23:23 *Asunto:* Re: [digitalradio] ROS Advantage? The hflink published ALE frequencies might be a good alternative for others around the world, since ALE users should not notice the FHSS ROS activity (according to the ROS documentation) and their soundings are infrequent and of short duration, so they should cause minimal interference to ROS activities.
Re: [digitalradio] Curious sound card modes question -
John, Given sufficient carrier suppression, any tone inputed to the microphone makes the transmitter output a pure RF carrier at a frequency of the suppressed carrier frequency plus the tone frequency for USB, or minus the tone frequency for LSB. Whatever you do with the tones determines what RF carriers come out. You can key the tones, or shift the tone frequencies, etc., and the RF output will follow. The ARRL Handbook usually has an explanation of this. Hope that answers the question. 73 - Skip KH6TY John wrote: So as to not continue growing the ROS legality discussion even further, I would like to ask a fairly simple question. How will the modulation be determined from any SSB transmitter when the source of the modulation is via the microphone audio input of that transmitter? Simply stated, how would any digital mode create anything other than some form of FSK simply by inputting a tone at the microphone input? Regardless of the software being used to generate the tone(s), at any given time there is nothing more than the absence or presence of a tone at the audio input of the transmitter. This is true of HRD's DM780, MixW modes, MMSSTV, or many other sound card driven software packages. They all have one thing in common, they generate a sequence of tones which is then processed by the very same transmitter in the very same way. The maximum output bandwidth is supposed to be somewhat limited in the bandpass of the transmitter circuitry (which is NOT being altered). Again, NO transmitter circuitry is being altered in any way that I am aware of. With this discussion, how do we arbitrarily change the transmitter output definitions? I am truly asking because that is a concept beyond my feeble mind. I really do not know. To me, regardless of the source of the modulation itself, the modulation still remains an offset of the carrier frequency by the frequency of the input tone. To me, the discussion of particular FCC designators for any of these modes is rather moot, unless there is some method to tie the two together. To simply start an argument about a particular FCC rule, without showing the correlation to the subject is somewhat like arguing the color of orange peels in an apple pie instruction sheet. They simply don't necessarily relate. Both may have valid points about their own arguments, but the tow simply do not go together. Am I missing something besides a few marbles now? My head is spinning from all these rules being bandied about, that may have no application here at all. John KE5HAM
[digitalradio] Re: GTOR- has anyone tried this?
I tried some connects with Andy and Skip and can confirm the sound card version of G-TOR works with a real G-TOR modem (my KAM-XL). Throughput got up to 200 baud and of course no errors due to the ARQ. The GUI is basic on the sound card program and not particularly intuitive but it seems that sound card G-TOR is possible on Windows. 73 Sholto K7TMG
[digitalradio] Re: Curious sound card modes question -
Thanks Skip, Unfortunately, this really does not get to the crux of my question(s). I understand how an SSB transmitter works, but that is not really what I am after. What I am driving at is if like this. If I use DM780 to run some version of digital mode via an SSB transceiver, it uses a tone or series of tone modulation/shifting to create the output of the transmitter, and not one single mode is called spread spectrum output, but is called FSK or PSK, etc. Now, we get into the aforementioned discussion regarding ROS, and suddenly, still via the microphone input of the same transmitter, those shifted frequencies are now called spread spectrum instead. I am having a great deal of difficulty understanding, other than the author happened to call his scheme spread spectrum in his technical documentation. Thanks John KE5HAM --- In digitalradio@yahoogroups.com, KH6TY kh...@... wrote: John, Given sufficient carrier suppression, any tone inputed to the microphone makes the transmitter output a pure RF carrier at a frequency of the suppressed carrier frequency plus the tone frequency for USB, or minus the tone frequency for LSB. Whatever you do with the tones determines what RF carriers come out. You can key the tones, or shift the tone frequencies, etc., and the RF output will follow. The ARRL Handbook usually has an explanation of this. Hope that answers the question. 73 - Skip KH6TY John wrote: So as to not continue growing the ROS legality discussion even further, I would like to ask a fairly simple question. How will the modulation be determined from any SSB transmitter when the source of the modulation is via the microphone audio input of that transmitter? Simply stated, how would any digital mode create anything other than some form of FSK simply by inputting a tone at the microphone input? Regardless of the software being used to generate the tone(s), at any given time there is nothing more than the absence or presence of a tone at the audio input of the transmitter. This is true of HRD's DM780, MixW modes, MMSSTV, or many other sound card driven software packages. They all have one thing in common, they generate a sequence of tones which is then processed by the very same transmitter in the very same way. The maximum output bandwidth is supposed to be somewhat limited in the bandpass of the transmitter circuitry (which is NOT being altered). Again, NO transmitter circuitry is being altered in any way that I am aware of. With this discussion, how do we arbitrarily change the transmitter output definitions? I am truly asking because that is a concept beyond my feeble mind. I really do not know. To me, regardless of the source of the modulation itself, the modulation still remains an offset of the carrier frequency by the frequency of the input tone. To me, the discussion of particular FCC designators for any of these modes is rather moot, unless there is some method to tie the two together. To simply start an argument about a particular FCC rule, without showing the correlation to the subject is somewhat like arguing the color of orange peels in an apple pie instruction sheet. They simply don't necessarily relate. Both may have valid points about their own arguments, but the tow simply do not go together. Am I missing something besides a few marbles now? My head is spinning from all these rules being bandied about, that may have no application here at all. John KE5HAM
[digitalradio] Curious sound card modes question -
So as to not continue growing the ROS legality discussion even further, I would like to ask a fairly simple question. How will the modulation be determined from any SSB transmitter when the source of the modulation is via the microphone audio input of that transmitter? Simply stated, how would any digital mode create anything other than some form of FSK simply by inputting a tone at the microphone input? Regardless of the software being used to generate the tone(s), at any given time there is nothing more than the absence or presence of a tone at the audio input of the transmitter. This is true of HRD's DM780, MixW modes, MMSSTV, or many other sound card driven software packages. They all have one thing in common, they generate a sequence of tones which is then processed by the very same transmitter in the very same way. The maximum output bandwidth is supposed to be somewhat limited in the bandpass of the transmitter circuitry (which is NOT being altered). Again, NO transmitter circuitry is being altered in any way that I am aware of. With this discussion, how do we arbitrarily change the transmitter output definitions? I am truly asking because that is a concept beyond my feeble mind. I really do not know. To me, regardless of the source of the modulation itself, the modulation still remains an offset of the carrier frequency by the frequency of the input tone. To me, the discussion of particular FCC designators for any of these modes is rather moot, unless there is some method to tie the two together. To simply start an argument about a particular FCC rule, without showing the correlation to the subject is somewhat like arguing the color of orange peels in an apple pie instruction sheet. They simply don't necessarily relate. Both may have valid points about their own arguments, but the tow simply do not go together. Am I missing something besides a few marbles now? My head is spinning from all these rules being bandied about, that may have no application here at all. John KE5HAM
[digitalradio] Re: ROS Advantage- mode ranking
--- In digitalradio@yahoogroups.com, Dave Ackrill dave.g0...@... wrote: Otherwise why so much RTTY on the bands? Even AX:25 is getting a bit long in the tooth now, but people still struggle on with it... My belief is that all the RTTY is largely from contesting and DX chasing. Those two operations have two things in common: they benefit from very fast turnaround, and the operators don't care much about the high error rate. Other modes like PSK31 have a longer turnaround time because they transmit for a second or so before and after the keyboard text, while RTTY is immediate and that translates into more contacts. The operators don't care much about all the errors because they already know what they want to see. They already know the call sign of the other station, and they already know the signal report will be 599, so if the mess on the screen looks like their call sign and QSL that is enough to consider it a contact. Then I guess there are a few people bringing old mechanical Teletype gear back to life and using it for rag-chewing for old times' sake. Jim W6JVE
Re: [digitalradio] Re: ROS Advantage- mode ranking
Not really Jim I for one never stopped using the old machines. Therefore never had to bring em back out. It's the only way I do RTTY here. John, W0JAB Then I guess there are a few people bringing old mechanical Teletype gear back to life and using it for rag-chewing for old times' sake. Jim W6JVE Try Hamspots, PSKreporter, and K3UK Sked Page http://www.obriensweb.com/skedpskr4.html Yahoo! Groups Links
Re: [digitalradio] Curious sound card modes question -
John wrote: How will the modulation be determined from any SSB transmitter when the source of the modulation is via the microphone audio input of that transmitter? Simply stated, how would any digital mode create anything other than some form of FSK simply by inputting a tone at the microphone input? Regardless of the software being used to generate the tone(s), at any given time there is nothing more than the absence or presence of a tone at the audio input of the transmitter. This is true of HRD's DM780, MixW modes, MMSSTV, or many other sound card driven software packages. They all have one thing in common, they generate a sequence of tones which is then processed by the very same transmitter in the very same way. The maximum output bandwidth is supposed to be somewhat limited in the bandpass of the transmitter circuitry (which is NOT being altered). Again, NO transmitter circuitry is being altered in any way that I am aware of. That's indeed the question! Given the way (legal) rigs filter the SSB to a voice grade bandwidth, it's really hard to see the many modes as anything but variants/nuances of AFSK, PSK, etc. And for what it's worth, spread spectrum is nearly always BPSK, just spread across many frequencies via some pseudo random or direct sequence. There are some technical descriptions of spread spectrum, and they nearly always consist of: 1- signal bandwidth to information bandwidth ratio significantly greater than one. (usually 100 or more) 2- Frequency shift driven by something other than the information itself. Item 1 actually is indicative of gain, the larger the ratio, the more effective the circuit gain is in terms of S/N. Given the low ratio in ROS, most definitions would exclude it based on this alone. A corollary to this is that a single bit must be spread across multiple frequencies. The larger the bandwidth expansion factor, the less of a bit is ever present on any single frequency. Item 2 is referring to sequence generators driving RF vco's directly, along with the signal in an adder mode. It is not referring to randomization of the in band audio signal, or even dividing the signal into multiple bands and sending information in parallel. Based on these measures, most ham grade transmitters would be incapable of spread spectrum operation. Pretty much all SS is a form of code division, as opposed to frequency division or time division. Code division is the clock signal (direct or random) which shifts the carrier frequency unrelated to the information modulation. IE: Even sending all zero's, ones or random data, the base frequency shift sequence will be the same. NTIA has two definitions for spread spectrum: 1. Telecommunications techniques in which a signal is transmitted in a bandwidth considerably greater than the frequency content of the original information. Note: Frequency hopping, direct sequence spreading, time scrambling, and combinations of these techniques are forms of spread spectrum. [INFOSEC-99] 2. A signal structuring technique that employs direct sequence, frequency hopping or a hybrid of these, which can be used for multiple access and/or multiple functions. This technique decreases the potential interference to other receivers while achieving privacy and increasing the immunity of spread spectrum receivers to noise and interference. Spread spectrum generally makes use of a sequential noise-like signal structure to spread the normally narrowband information signal over a relatively wide band of frequencies. The receiver correlates the signals to retrieve the original information signal. [NTIA] ROS appears to me to be a neat audio j3? mode using spread spectrum type techniques. But does not meet the technical definition of spread spectrum by FS-1037C or subsequent NTIA definitions. You could say it does have some aspects of the non-technical SS NTIA definition. IE: interference noise immunity. All that said neat idea, nice to see a new mode! Have fun, Alan km4ba
Re: [digitalradio] Curious sound card modes question -
Nothing is altered. In a SSB transmitter, amplitudes are scaled (usually UP) and frequencies just shifted. So, if audio tones change frequency, RF tones do likewise. 73, Jose, CO2JA --- El 22/02/2010 18:04, John escribió: So as to not continue growing the ROS legality discussion even further, I would like to ask a fairly simple question. How will the modulation be determined from any SSB transmitter when the source of the modulation is via the microphone audio input of that transmitter? Simply stated, how would any digital mode create anything other than some form of FSK simply by inputting a tone at the microphone input? Regardless of the software being used to generate the tone(s), at any given time there is nothing more than the absence or presence of a tone at the audio input of the transmitter. This is true of HRD's DM780, MixW modes, MMSSTV, or many other sound card driven software packages. They all have one thing in common, they generate a sequence of tones which is then processed by the very same transmitter in the very same way. The maximum output bandwidth is supposed to be somewhat limited in the bandpass of the transmitter circuitry (which is NOT being altered). Again, NO transmitter circuitry is being altered in any way that I am aware of. With this discussion, how do we arbitrarily change the transmitter output definitions? I am truly asking because that is a concept beyond my feeble mind. I really do not know. To me, regardless of the source of the modulation itself, the modulation still remains an offset of the carrier frequency by the frequency of the input tone. To me, the discussion of particular FCC designators for any of these modes is rather moot, unless there is some method to tie the two together. To simply start an argument about a particular FCC rule, without showing the correlation to the subject is somewhat like arguing the color of orange peels in an apple pie instruction sheet. They simply don't necessarily relate. Both may have valid points about their own arguments, but the tow simply do not go together. Am I missing something besides a few marbles now? My head is spinning from all these rules being bandied about, that may have no application here at all. John KE5HAM
Re: [digitalradio] Re: Curious sound card modes question -
It will be spread spectrum if the tone frequencies are controlled by a code as explained in the ROS documentation: A system is defined to be a spread-spectrum system if it fulfills the following requirements: 1. The signal occupies a bandwidth much in excess of the minimum bandwidth necessary to send the information. 2. Spreading is accomplished by means of a spreading signal, often called a code signal, which is independent of the data. 3. At the receiver, despreading (recovering the original data) is accomplished by the correlation of the received spread signal with a synchronized replica of the spreading signal used to spread the information. Standard modulation schemes as frequency modulation and pulse code modulation also spread the spectrum of an information signal, but they do not qualify as spread-spectrum systems since they do not satisfy all the conditions outlined above. Note that all three conditions must be met to be considered spread spectrum. I don;t know if it would be possible to send the data in less bandwidth, but, for example, PSK31 accomplishes the same typing speed in a bandwidth of 31 Hz, instead of in 2000 Hz, so ROS is probably truly spread-spectrum. Remember that spread spectrum was conceived as a way of coding transmissions so they could not be intercepted and decoded. In fact actress Hedy Lamarr invented spread spectrum, and you can read that here: http://en.wikipedia.org/wiki/Hedy_Lamarr. The difference is the use of a code to spread the data and signals to avoid detection and monitoring by those without the same code. Download the documentation from www. rosmodem.wordpress.com and read about spread spectrum and the ROS implementation. That will make it clear I think. Remembering that a single tone creates a single RF carrier makes it easy to see how just about anything can be done with tones, including sending data over several tones at once so if one carrier is lost, others carry the same data, or using a psuedo-random code to determine the carrier frequencies, as I think is done in ROS. That documentation also explains the difference between FHSS and modes like MFSK16. However, a main point is that the data does not have to be scattered over such a wide bandwidth to achieve communication, but ROS does, so it qualifies as spread spectrum. If you have a receive bandwith of 10,000 Hz, and you spread over that bandwidth, you really are using way more bandwidth than necessary to send the same data at a given speed. MT63 uses 64 carriers with the data divided among the carriers for redundancy and about 40% of the signal can be obilterated by QRM and still produce good copy. I think the difference with ROS is that the carrier frequencies are varied according to a code, instead of being at a fixed position, but I am no expert on modes, so someone else can probably explain it better and with more accuracy. Generally it is qualifies as spread spectrum if a code is used for the spreading, and in military communications (and even cell phones, I think) the code prevents anyone else from reconstructing the signal so that the intelligence can be recovered if they do not possess the same code. 73 - Skip KH6TY John wrote: Thanks Skip, Unfortunately, this really does not get to the crux of my question(s). I understand how an SSB transmitter works, but that is not really what I am after. What I am driving at is if like this. If I use DM780 to run some version of digital mode via an SSB transceiver, it uses a tone or series of tone modulation/shifting to create the output of the transmitter, and not one single mode is called spread spectrum output, but is called FSK or PSK, etc. Now, we get into the aforementioned discussion regarding ROS, and suddenly, still via the microphone input of the same transmitter, those shifted frequencies are now called spread spectrum instead. I am having a great deal of difficulty understanding, other than the author happened to call his scheme spread spectrum in his technical documentation. Thanks John KE5HAM --- In digitalradio@yahoogroups.com mailto:digitalradio%40yahoogroups.com, KH6TY kh...@... wrote: John, Given sufficient carrier suppression, any tone inputed to the microphone makes the transmitter output a pure RF carrier at a frequency of the suppressed carrier frequency plus the tone frequency for USB, or minus the tone frequency for LSB. Whatever you do with the tones determines what RF carriers come out. You can key the tones, or shift the tone frequencies, etc., and the RF output will follow. The ARRL Handbook usually has an explanation of this. Hope that answers the question. 73 - Skip KH6TY John wrote: So as to not continue growing the ROS legality discussion even further, I would like to ask a fairly simple question. How will the modulation be determined from any SSB transmitter when the source of the modulation is via the
Re: [digitalradio] Re: Curious sound card modes question -
John wrote: Thanks Skip, Unfortunately, this really does not get to the crux of my question(s). I understand how an SSB transmitter works, but that is not really what I am after. What I am driving at is if like this. If I use DM780 to run some version of digital mode via an SSB transceiver, it uses a tone or series of tone modulation/shifting to create the output of the transmitter, and not one single mode is called spread spectrum output, but is called FSK or PSK, etc. Now, we get into the aforementioned discussion regarding ROS, and suddenly, still via the microphone input of the same transmitter, those shifted frequencies are now called spread spectrum instead. I am having a great deal of difficulty understanding, other than the author happened to call his scheme spread spectrum in his technical documentation. OFDM used in Pactor 3 is legal due to it's low symbol rates and SSB sized effective bandwidth. If prior to P3 someone asked if FDM was legal on HF most would say no. Traditional FDM (frequency division multiplexing) as practiced in the real world would not ever be legal on HF. So technically it's FDM, but practically, it's not, as it's much narrower bandwidth. Lumping ROS in with Spread spectrum is similar. You can use FDM or SS approaches on an audio modulated sideband signal and not meet practical definitions. quack test- walks like a duck, must be a duck. Regarding the perfect SSB transmitter sending a 1khz tone equaling CW at a 1khz beat frequency, we all know there is a big difference between theoretical and reality. But in theory, ROS, P3, whatever could be represented by multiple transmitter signals, so could technically fall into legal gray area. I'm sure if we tried hard enough we could find a way to decide it's illegal, and should be banned. And in reality, the FCC won't care, as it did not meet the quack test of spread spectrum. :-) I don't have a horse in this race, however. :-) Have fun, Alan KM4BA
Re: [digitalradio] Re: Curious sound card modes question -
The only entity competent to answer the question is the FCC, and the accepted procedure when one is not sure is to ask for a clarification. Unfortunately, it is everyone's legal responsibility to understand the law and obey it. Since most of use cannot do that, we have to turn to lawyers to do it. You may or may not like the answer given, but the FCC does try to protect the ham bands for everyone and seems to make interpretations on that basis. Digital users are a tiny minority of users of the bands, but the FCC is accountable to all hams, so they must try to do what is right for all hams, not just for a minority. If it were not for that approach, the HF bands today might be covered with automatic messaging systems and it would be hard to even find a place to play or have a QSO without interference from an automatic station that does not listen first, does not QRL, and does not share frequencies. We may not like the time it takes for the process to play out, but that gives everyone a chance to present their case before any rules are made - EVERYONE, not just a vocal minority. 73 - Skip KH6TY Alan Barrow wrote: John wrote: Thanks Skip, Unfortunately, this really does not get to the crux of my question(s). I understand how an SSB transmitter works, but that is not really what I am after. What I am driving at is if like this. If I use DM780 to run some version of digital mode via an SSB transceiver, it uses a tone or series of tone modulation/shifting to create the output of the transmitter, and not one single mode is called spread spectrum output, but is called FSK or PSK, etc. Now, we get into the aforementioned discussion regarding ROS, and suddenly, still via the microphone input of the same transmitter, those shifted frequencies are now called spread spectrum instead. I am having a great deal of difficulty understanding, other than the author happened to call his scheme spread spectrum in his technical documentation. OFDM used in Pactor 3 is legal due to it's low symbol rates and SSB sized effective bandwidth. If prior to P3 someone asked if FDM was legal on HF most would say no. Traditional FDM (frequency division multiplexing) as practiced in the real world would not ever be legal on HF. So technically it's FDM, but practically, it's not, as it's much narrower bandwidth. Lumping ROS in with Spread spectrum is similar. You can use FDM or SS approaches on an audio modulated sideband signal and not meet practical definitions. quack test- walks like a duck, must be a duck. Regarding the perfect SSB transmitter sending a 1khz tone equaling CW at a 1khz beat frequency, we all know there is a big difference between theoretical and reality. But in theory, ROS, P3, whatever could be represented by multiple transmitter signals, so could technically fall into legal gray area. I'm sure if we tried hard enough we could find a way to decide it's illegal, and should be banned. And in reality, the FCC won't care, as it did not meet the quack test of spread spectrum. :-) I don't have a horse in this race, however. :-) Have fun, Alan KM4BA
RE: [digitalradio] Re: Curious sound card modes question -
re PSK31 accomplishes the same typing speed in a bandwidth of 31 Hz, instead of in 2000 Hz, so ROS is probably truly spread-spectrum. Applying this logic to RTTY, which employs ~10X the bandwidth employed by PSK31, would lead us to conclude that RTTY is also spread spectrum. 73, Dave, AA6YQ -Original Message- From: digitalradio@yahoogroups.com [mailto:digitalra...@yahoogroups.com]on Behalf Of KH6TY Sent: Monday, February 22, 2010 8:30 PM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Re: Curious sound card modes question - It will be spread spectrum if the tone frequencies are controlled by a code as explained in the ROS documentation: A system is defined to be a spread-spectrum system if it fulfills the following requirements: 1. The signal occupies a bandwidth much in excess of the minimum bandwidth necessary to send the information. 2. Spreading is accomplished by means of a spreading signal, often called a code signal, which is independent of the data. 3. At the receiver, despreading (recovering the original data) is accomplished by the correlation of the received spread signal with a synchronized replica of the spreading signal used to spread the information. Standard modulation schemes as frequency modulation and pulse code modulation also spread the spectrum of an information signal, but they do not qualify as spread-spectrum systems since they do not satisfy all the conditions outlined above. Note that all three conditions must be met to be considered spread spectrum. I don;t know if it would be possible to send the data in less bandwidth, but, for example, PSK31 accomplishes the same typing speed in a bandwidth of 31 Hz, instead of in 2000 Hz, so ROS is probably truly spread-spectrum. Remember that spread spectrum was conceived as a way of coding transmissions so they could not be intercepted and decoded. In fact actress Hedy Lamarr invented spread spectrum, and you can read that here: http://en.wikipedia.org/wiki/Hedy_Lamarr. The difference is the use of a code to spread the data and signals to avoid detection and monitoring by those without the same code. Download the documentation from www. rosmodem.wordpress.com and read about spread spectrum and the ROS implementation. That will make it clear I think. Remembering that a single tone creates a single RF carrier makes it easy to see how just about anything can be done with tones, including sending data over several tones at once so if one carrier is lost, others carry the same data, or using a psuedo-random code to determine the carrier frequencies, as I think is done in ROS. That documentation also explains the difference between FHSS and modes like MFSK16. However, a main point is that the data does not have to be scattered over such a wide bandwidth to achieve communication, but ROS does, so it qualifies as spread spectrum. If you have a receive bandwith of 10,000 Hz, and you spread over that bandwidth, you really are using way more bandwidth than necessary to send the same data at a given speed. MT63 uses 64 carriers with the data divided among the carriers for redundancy and about 40% of the signal can be obilterated by QRM and still produce good copy. I think the difference with ROS is that the carrier frequencies are varied according to a code, instead of being at a fixed position, but I am no expert on modes, so someone else can probably explain it better and with more accuracy. Generally it is qualifies as spread spectrum if a code is used for the spreading, and in military communications (and even cell phones, I think) the code prevents anyone else from reconstructing the signal so that the intelligence can be recovered if they do not possess the same code. 73 - Skip KH6TY John wrote: Thanks Skip, Unfortunately, this really does not get to the crux of my question(s). I understand how an SSB transmitter works, but that is not really what I am after. What I am driving at is if like this. If I use DM780 to run some version of digital mode via an SSB transceiver, it uses a tone or series of tone modulation/shifting to create the output of the transmitter, and not one single mode is called spread spectrum output, but is called FSK or PSK, etc. Now, we get into the aforementioned discussion regarding ROS, and suddenly, still via the microphone input of the same transmitter, those shifted frequencies are now called spread spectrum instead. I am having a great deal of difficulty understanding, other than the author happened to call his scheme spread spectrum in his technical documentation. Thanks John KE5HAM --- In digitalradio@yahoogroups.com, KH6TY kh...@... wrote: John, Given sufficient carrier suppression, any tone inputed to the microphone makes the transmitter output a pure RF carrier at a frequency of the suppressed carrier frequency plus the tone frequency for USB, or minus the tone frequency for LSB. Whatever you do with the tones
Re: [digitalradio] Re: Curious sound card modes question -
That is only ONE of the three conditions outlined by Jose. I thought I did not need to repeat the other two. 73 - Skip KH6TY Dave AA6YQ wrote: re PSK31 accomplishes the same typing speed in a bandwidth of 31 Hz, instead of in 2000 Hz, so ROS is probably truly spread-spectrum. Applying this logic to RTTY, which employs ~10X the bandwidth employed by PSK31, would lead us to conclude that RTTY is also spread spectrum. 73, Dave, AA6YQ -Original Message- *From:* digitalradio@yahoogroups.com [mailto:digitalra...@yahoogroups.com]*on Behalf Of *KH6TY *Sent:* Monday, February 22, 2010 8:30 PM *To:* digitalradio@yahoogroups.com *Subject:* Re: [digitalradio] Re: Curious sound card modes question - It will be spread spectrum if the tone frequencies are controlled by a code as explained in the ROS documentation: A system is defined to be a spread-spectrum system if it fulfills the following requirements: 1. The signal occupies a bandwidth much in excess of the minimum bandwidth necessary to send the information. 2. Spreading is accomplished by means of a spreading signal, often called a code signal, which is independent of the data. 3. At the receiver, despreading (recovering the original data) is accomplished by the correlation of the received spread signal with a synchronized replica of the spreading signal used to spread the information. Standard modulation schemes as frequency modulation and pulse code modulation also spread the spectrum of an information signal, but they do not qualify as spread-spectrum systems since they do not satisfy all the conditions outlined above. Note that all three conditions must be met to be considered spread spectrum. I don;t know if it would be possible to send the data in less bandwidth, but, for example, PSK31 accomplishes the same typing speed in a bandwidth of 31 Hz, instead of in 2000 Hz, so ROS is probably truly spread-spectrum. Remember that spread spectrum was conceived as a way of coding transmissions so they could not be intercepted and decoded. In fact actress Hedy Lamarr invented spread spectrum, and you can read that here: http://en.wikipedia.org/wiki/Hedy_Lamarr. The difference is the use of a code to spread the data and signals to avoid detection and monitoring by those without the same code. Download the documentation from www. rosmodem.wordpress.com and read about spread spectrum and the ROS implementation. That will make it clear I think. Remembering that a single tone creates a single RF carrier makes it easy to see how just about anything can be done with tones, including sending data over several tones at once so if one carrier is lost, others carry the same data, or using a psuedo-random code to determine the carrier frequencies, as I think is done in ROS. That documentation also explains the difference between FHSS and modes like MFSK16. However, a main point is that the data does not have to be scattered over such a wide bandwidth to achieve communication, but ROS does, so it qualifies as spread spectrum. If you have a receive bandwith of 10,000 Hz, and you spread over that bandwidth, you really are using way more bandwidth than necessary to send the same data at a given speed. MT63 uses 64 carriers with the data divided among the carriers for redundancy and about 40% of the signal can be obilterated by QRM and still produce good copy. I think the difference with ROS is that the carrier frequencies are varied according to a code, instead of being at a fixed position, but I am no expert on modes, so someone else can probably explain it better and with more accuracy. Generally it is qualifies as spread spectrum if a code is used for the spreading, and in military communications (and even cell phones, I think) the code prevents anyone else from reconstructing the signal so that the intelligence can be recovered if they do not possess the same code. 73 - Skip KH6TY John wrote: Thanks Skip, Unfortunately, this really does not get to the crux of my question(s). I understand how an SSB transmitter works, but that is not really what I am after. What I am driving at is if like this. If I use DM780 to run some version of digital mode via an SSB transceiver, it uses a tone or series of tone modulation/shifting to create the output of the transmitter, and not one single mode is called spread spectrum output, but is called FSK or PSK, etc. Now, we get into the aforementioned discussion regarding ROS, and suddenly, still via the microphone input of the same transmitter, those shifted frequencies are now called spread spectrum instead. I am having a great deal of difficulty understanding, other than the author happened to call his scheme spread spectrum in his technical documentation. Thanks John KE5HAM --- In digitalradio@yahoogroups.com mailto:digitalradio%40yahoogroups.com, KH6TY kh...@... wrote: John, Given sufficient carrier
Re: [digitalradio] Re: Curious sound card modes question -
Gentlemen, I have spent way too much time with my limited knowledge trying to make some sense of this issue and answer questions. I am going to use ROS on UHF only anyway, and it is legal there no matter if it is FHSS or not, so I'll leave it to the rest of you to discuss the issue. Thanks for the bandwidth and I hope it can be used on HF! 73, Skip, KH6TY
Re: [digitalradio] Re: Curious sound card modes question -
KH6TY wrote: It will be spread spectrum if the tone frequencies are controlled by a code as explained in the ROS documentation: A system is defined to be a spread-spectrum system if it fulfills the following requirements: 1. The signal occupies a bandwidth much in excess of the minimum bandwidth necessary to send the information. 2. Spreading is accomplished by means of a spreading signal, often called a code signal, which is independent of the data. 3. At the receiver, despreading (recovering the original data) is accomplished by the correlation of the received spread signal with a synchronized replica of the spreading signal used to spread the information. Standard modulation schemes as frequency modulation and pulse code modulation also spread the spectrum of an information signal, but they do not qualify as spread-spectrum systems since they do not satisfy all the conditions outlined above. Note that all three conditions must be met to be considered spread spectrum. I don;t know if it would be possible to send the data in less bandwidth, but, for example, PSK31 accomplishes the same typing speed in a bandwidth of 31 Hz, instead of in 2000 Hz, so ROS is probably truly spread-spectrum. The key is the much in excess in item 1. If you were to use 31hz vs 2000, you'd be approaching the minimum bandwidth expansion factor in practical usage at 64:1. I'd have to go look at realistic bandwidth for psk, I was thinking it's a bit higher in the real world. Modern SS runs way higher, often 1000:1. But just like the fsk symbol rate anachronism in the regs, I suspect the spread spectrum restriction in the regs was targeted the very broad (50-100khz minimum) spread spectrum signals. Realistically, they did not anticipate that we'd have the capability to do SS in a 2khz signal. (and we probably could not have pre-sound card) But after reading the NTIA definition, and the one in the docs, I agree it's technically SS by a strict interpretation. Just like P3 is technically FDM. But since both live in a SSB signal bandwidth, they are not what the regs were trying to prevent. Based on the FCC ruling on P3 OFDM, my suspicion is they'd fall in favor of ROS. I don't see a practical reason for them to disallow it, it does not have expanded footprint, etc. But all this points out to me how out of date the US regs are! It would be easier if they had used the NTIA definition, and ideally put some practical measures around bandwidth expansion factor and overall bandwidth. No matter what, it's a neat idea, and thanks for taking the time to code it! have fun, Alan km4ba
[digitalradio] Something to consider about external automatic antenna tuners
This is for anyone thinking about an external automatic antenna tuner. It is not meant as an endorsement or indictment of these devices. I operate CW, digital, and once in a while SSB. Because of the vastly different operating frequencies, no one antenna can work perfectly on every one. My IC-746 (non-Pro) has a very good auto-tuner built in, but it wasn't quite good enough to cover all the frequencies I use. I decided to get an external ATU. I decided on the LDG AT-200Pro and have been using it now for several months. The tuner works great. It tunes quickly on a new frequency, and has more than enough memories to remember all the various settings for all the bands and frequencies I operate on. It also has manual overrides should they be needed. However, there is one thing the tuner will NOT do. It will not remember any band or frequency, until the transmitter is keyed. For example: I operate CW on 14.035 for a period of time. I then have a CW sked on 18.075. After the sked I move back to 14.035. The tuner is still set for the last transmission, which was on 18.075. Until I transmit on 14.035 again, the signals are a bit attenuated, since the tuner is set for a different frequency. My IC-746 built-in tuner remembered the tuner settings for each band. In fact, I believe with the triple-stacking band registers that it would remember three settings per band. I suspect most modern rigs probably have the same performance. To be fair, it only takes a very short time to transmit a low-power pulse that will activate the tuner's memory for the frequency, but it IS an extra step that may not be welcome when working a contest or DX. In my situation, the ability to quickly tune a wide variety of frequencies quickly, outweighs the downside stated. I only point this out for benefit of anyone considering the addition of an outboard tuner. 73 Dave KB3MOW
Re: [digitalradio] Has anyone tried this?
G-Tor was only useable by the Kantronics line of TNCs years ago, like Clover and HAL gear. 73 Buddy WB4M - Original Message - From: sholtofish sho...@probikekit.com To: digitalradio@yahoogroups.com Sent: Monday, February 22, 2010 5:12 PM Subject: [digitalradio] Has anyone tried this? Came across this the other day: http://db0lj.prgm.org/boxfiles/software/Gtor.zip Looks like it's a sound card implementation of G-TOR?? Seems to have a butterfly icon so something to do with MixW?? Does it work? Try Hamspots, PSKreporter, and K3UK Sked Page http://www.obriensweb.com/skedpskr4.html Yahoo! Groups Links
Re: [digitalradio] Re: ROS Advantage- mode ranking
jhaynesatalumni wrote: - My belief is that all the RTTY is largely from contesting and DX chasing. Those two operations have two things in common: Another aspect I had not thought of until I asked a DX'er friend of mine why they did not use PSK much for DX. His answer: no one has found a good way to do psk spots. Most DX is spot click initially. I see some psk spots, but there is wide variation in how people spot them. so you have to (heaven forbid) listen to the psk signals to see which one is the dx. :-) I've also observed a significant power mindset with many RTTY ops. Bigger is better. I also see that for many RTTY ops it's not love of the mode, but another way to add DX credit. Sweeping generalization, of course. But I have more respect for the guy with the ASR. I'm not anti-DX, but do believe it often leads to some bad operating practices. Have fun, Alan km4ba
[digitalradio] PSK SPOTS
That is a good point, Alan. Now that i think about it, you would think that after 10 years we would have come up with a point and click method. Andy K3UK On Mon, Feb 22, 2010 at 9:26 PM, Alan Barrow ml9...@pinztrek.com wrote: jhaynesatalumni wrote: - My belief is that all the RTTY is largely from contesting and DX chasing. Those two operations have two things in common: Another aspect I had not thought of until I asked a DX'er friend of mine why they did not use PSK much for DX. His answer: no one has found a good way to do psk spots. Most DX is spot click initially. I see some psk spots, but there is wide variation in how people spot them. so you have to (heaven forbid) listen to the psk signals to see which one is the dx. :-)
[digitalradio] Re: ROS Advantage- mode ranking
--- In digitalradio@yahoogroups.com, Alan Barrow ml9...@... wrote: I've also observed a significant power mindset with many RTTY ops. Bigger is better. This pretty much comes with the territory. I've been in RTTY since the late 1950s, and I just remembered recently that back then we all ran lots of power - had to, to get good copy. I used a home-built 500 watt transmitter for a number of years, then switched to a TMC rig with a KW linear amplifier. Used that until the AMTOR mode came along, and then I got a TS-940 and used that barefoot and other radios in the 50-100 watt class ever since. And I don't do much RTTY anymore, but then nobody else does either except the DX guys and contesters.
[digitalradio] Re: Something to consider about external automatic antenna tuners
--- In digitalradio@yahoogroups.com, Dave 'Doc' Corio dco...@... wrote: However, there is one thing the tuner will NOT do. It will not remember any band or frequency, until the transmitter is keyed. Well, sure. The only thing going from the radio to the tuner is the antenna cable, so the tuner has no way to know that you have changed frequency on the transceiver. Whereas a tuner built into the radio, or one made for the radio you have and connecting to the radio with a control cable, can get frequency information from the radio. But the third-party tuner only knows you have changed frequency when you tickle it with some RF.
[digitalradio] Re: GTOR- has anyone tried this?
--- In digitalradio@yahoogroups.com, sholtofish sho...@... wrote: I tried some connects with Andy and Skip and can confirm the sound card version of G-TOR works with a real G-TOR modem (my KAM-XL). Throughput got up to 200 baud and of course no errors due to the ARQ. The GUI is basic on the sound card program and not particularly intuitive but it seems that sound card G-TOR is possible on Windows. 73 Sholto K7TMG That's really interesting. I had no idea there was a sound card modem for G-TOR, and of course G-TOR has seen very little use since you always had to have a Kantronics TNC to use it. Maybe somebody can write up how to operate the sound card version.
[digitalradio] Re: Curious sound card modes question -
--- In digitalradio@yahoogroups.com, John ke5h...@... wrote: Thanks Skip, Unfortunately, this really does not get to the crux of my question(s). I understand how an SSB transmitter works, but that is not really what I am after. What I am driving at is if like this. If I use DM780 to run some version of digital mode via an SSB transceiver, it uses a tone or series of tone modulation/shifting to create the output of the transmitter, and not one single mode is called spread spectrum output, but is called FSK or PSK, etc. Now, we get into the aforementioned discussion regarding ROS, and suddenly, still via the microphone input of the same transmitter, those shifted frequencies are now called spread spectrum instead. I am having a great deal of difficulty understanding, other than the author happened to call his scheme spread spectrum in his technical documentation. That's a good question. If we run RTTY with 850 Hz shift like we did in the old days, has that turned into spread spectrum?
[digitalradio] Re: ROS Advantage- mode ranking
--- In digitalradio@yahoogroups.com, John Becker, WØJAB w0...@... wrote: Not really Jim I for one never stopped using the old machines. Therefore never had to bring em back out. It's the only way I do RTTY here. John, W0JAB Cool! I have a lot of TTY machinery out in my baudy house but none of it is on the air right now. I switched to sound card RTTY back when K6STI's RITTY software first came out. At my request he did make available a cleaned-up Baudot output on one of the connector pins so I could drive a Real Teletype printer from it.
[digitalradio] Re: GTOR- has anyone tried this?
A SOFTWARE G-TOR FOR SOUNDCARD? WHERE MIGHT IT BE FOUND. DAIVD/WD4KPD
Re: [digitalradio] Re: Curious sound card modes question -
No, the shift on RTTY and other soundcard modes is not determined by a pseudo random code but always known and predictable. Instead, the tones on ROS are driven by a code signal. To quote from the ROS documentation, 2. Spreading is accomplished by means of a spreading signal, often called a code signal, which is independent of the data. The original intent of spread spectrum was to make it impossible to monitor without possessing the despreading code, but ROS can be monitored. There is a good chance that the FCC will allow us to use ROS on HF - why not! But as the rules are written right now, ROS is FHSS - by design, and it does not matter if the description is changed or not, so it is necessary to get a waiver or other FCC agreement that we can use it on HF. ROS can be copied by third parties, and is no wider than a phone signal, so I cannot think of any reason the FCC would decline, but they have to give permission. That is just the way it works, because that is how the rules happen to have been written in the past. If the spreading is NOT actually accomplished by means of a spreading signal, often called a code signal, which is independent of the data then ROS is not spread spectrum and there is no problem. 73 - Skip KH6TY jhaynesatalumni wrote: --- In digitalradio@yahoogroups.com mailto:digitalradio%40yahoogroups.com, John ke5h...@... wrote: Thanks Skip, Unfortunately, this really does not get to the crux of my question(s). I understand how an SSB transmitter works, but that is not really what I am after. What I am driving at is if like this. If I use DM780 to run some version of digital mode via an SSB transceiver, it uses a tone or series of tone modulation/shifting to create the output of the transmitter, and not one single mode is called spread spectrum output, but is called FSK or PSK, etc. Now, we get into the aforementioned discussion regarding ROS, and suddenly, still via the microphone input of the same transmitter, those shifted frequencies are now called spread spectrum instead. I am having a great deal of difficulty understanding, other than the author happened to call his scheme spread spectrum in his technical documentation. That's a good question. If we run RTTY with 850 Hz shift like we did in the old days, has that turned into spread spectrum?
Re: [digitalradio] Re: Curious sound card modes question -
On Mon, Feb 22, 2010 at 08:30:29PM -0500, KH6TY wrote: It will be spread spectrum if the tone frequencies are controlled by a code as explained in the ROS documentation: A system is defined to be a spread-spectrum system if it fulfills the following requirements: 1. The signal occupies a bandwidth much in excess of the minimum bandwidth necessary to send the information. 2. Spreading is accomplished by means of a spreading signal, often called a code signal, which is independent of the data. 3. At the receiver, despreading (recovering the original data) is accomplished by the correlation of the received spread signal with a synchronized replica of the spreading signal used to spread the information. Standard modulation schemes as frequency modulation and pulse code modulation also spread the spectrum of an information signal, but they do not qualify as spread-spectrum systems since they do not satisfy all the conditions outlined above. Note that all three conditions must be met to be considered spread spectrum. I don;t know if it would be possible to send the data in less bandwidth, but, for example, PSK31 accomplishes the same typing speed in a bandwidth of 31 Hz, instead of in 2000 Hz, so ROS is probably truly spread-spectrum. Remember that spread spectrum was conceived as a way of coding transmissions so they could not be intercepted and decoded. In fact actress Hedy Lamarr invented spread spectrum, and you can read that here: http://en.wikipedia.org/wiki/Hedy_Lamarr. The difference is the use of a code to spread the data and signals to avoid detection and monitoring by those without the same code. She invented FHSS as a torpedo control technique; most folks don't know that she had an EE degree. DSSS came about later, as a classified technique called Phantom, to permit transmissions with a low probability of interception (LPI). With a typical 3 KHz bandwidth receiver, or even a 50 KHz wide panadaptor, you won't see all the spectrum from a wideband (say, 100 KHz spreading code) DSSS transmission. You may notice only a slightly raised noise floor. But that's only part of the deal with DSSS. The correlation and despreading produces a really nice gain in noise immunity, as well. -- Mike Andrews, W5EGO mi...@mikea.ath.cx Tired old sysadmin
Re: [digitalradio] ROS Advantage?
Hi All. Just a question, and please, be patient if I'm asking this... I'm a SWL and I decoded ros in last days, but HOW MUCH is large its bandwidth ? In other words, which is the minimun value of bandwidth enough to receive/decode ros ? Best regards and thanks in advance for any reply. 73 de Ugo - SWL 1281/VE (sent with iPhone) Il giorno 22/feb/2010, alle ore 22.33, KH6TY kh...@comcast.net ha scritto: Hi Jose, Of course we start that way (using a SSB filter), but then a Pactor station will come on, cover the upper fourth of the ROS signal, and decoding becomes garbage until it leaves. With a more narrow mode, the Pactor station can just be filtered out at IF frequencies and not affect either the AGC or the decoding of something like MFSK16 or Olivia 16-500, as long as those signals are sufficiently away from the Pactor signal (even if they are still within the bandwidth of a ROS signal). In the case of CW stations, during the contest, they just appeared in the SSB filter bandwidth, and therefore among the ROS tones, and some of those also stopped decoding until they left. Let's say a MT63-500 signal appears at 2000 Hz tone frequency (i.e. covering from 2000 to 2500 Hz) at the same signal strength as the ROS signal. Will ROS stop decoding? If a MT-63-1000 signal appears at 1500 Hz tone frequency, will ROS stop decoding? If this happens and there is a more narrowband signal like MFSK16, for instance, covering from 500 Hz to 1000 Hz, the MFSK16 signal can coexist with the MT63 signal unless the MT63 signal has captured the AGC and cutting the gain. If it has, then passband tuning can cut out the MT63 signal, leaving only the MFSK16 signal undisturbed and decoding. In other words, there is less chance for an interfering signal to partially or completely cover a more narrow signal that there is a much wider one, unless the wider one can still decode with half or 25% of its tones covered up. The question posed is how well ROS can handle QRM, and that is what I tried to see. If ROS can withstand half of its bandwidth covered with an interfering signal and still decode properly then I cannot explain what I saw, but decoding definitely stopped or changed to garbage when the Pactor signal came on. 73 - Skip KH6TY jose alberto nieto ros wrote: Hi, You must not filter anything in the transceiver. You must pass all bandwith in your receiver because filter are doing by the PC better than you transceiver. De: KH6TY kh...@comcast.net Para: digitalradio@yahoogroups.com Enviado: lun,22 febrero, 2010 18:31 Asunto: Re: [digitalradio] ROS Advantage? Howard, After monitoring 14.101 continuously for two days, I find the following: 1. CW signals (of narrow width, of course) during this past weekend contest often disrupted decoding, and it looks like it was not desensitization due to AGC capture, as the ROS signals on the waterfall did not appear any weaker. 2. Pactor signals of 500 Hz width, outside the ROS signal, that capture the AGC, do desensitize the receiver and cause loss of decoding, as expected. Passband tuning takes care of that problem however. 3. Pactor signals which have the same degree of darkness as the ROS carriers, and occur within the upper third of the ROS signal, cause loss of decoding, and it is not possible to fix the problem with passband tuning, as trying to do that appears to take away enough of the ROS signal that the degree of frequency hopping used is insufficient to overcome. Receiver is the IC-746Pro. 4. If more than one ROS signal is present on the frequency, ROS will decode one of them - apparently the strongest one - and the weaker one is blanked out until the stronger one goes away and the the weaker one is decoded. 5. Compared to Olivia 16-500, for example, the width of the ROS signal seems to be a disadvantage as far as handling QRM is concerned. Five Olivia 16-500 signals will fit in the same space as one ROS signal needs, so QRM, covering the top 40% of the ROS signal, for example, would probably not disrupt any of three Olivia signals in the bottom 60% of the ROS signal bandwidth. In other words, the wide bandwidth required for ROS to work is a disadvantage because IF filtering cannot remove narrower band QRM signals that fall within the area of the ROS signal, but IF filtering can remove the same QRM from the passband that has been narrowed to accept only an Olivia signal. A much wider expansion or spectrum spread might reduce the probability of decoding disruption, but that also makes the signal wider still and more susceptible to additional QRM. The advantage of FHSS appears to be more in favor of making it hard to copy a traditional SS signal unless the code is available, than QRM survival, but on crowded ham bands, it looks like a sensitive mode like Olivia or MFSK16, because it is more narrow, and filters can be tighter,
[digitalradio] Re: Curious sound card modes question -
Thanks I think you make the same point as I am seeking Just because the author of the program calls his great work spread spectrum does not necessarily make it so. Sorry Jose Here is partially why I ask for better clarification In Jose's documentation, one of his remarks seems to actually remove a qualifier of spread spectrum by his own statement as to why he did not do certain things. That is, in every spread spectrum system I have ever worked with (microwave, cordless phones, and numerous others), for the systems to work, each end had to be pre-programmed to a matching specific coded algorithm in order for the receivers and transmitters to hop frequencies in the exact same pattern and sync with each other. This pattern was pre-determined by that algorithm and NOT by ANY of the input data whatsoever. In other words, even if there were no input to the transmitter, it would still hop and transmit on it's pre-determined frequency pattern. The presence or absence of data at any given point in time would certainly affect the output of the transmitter at that particular instant, but would not affect the pre-determined frequency, but rather it's phase usually. NOW, with that said, this also would cause one other thing to happen, that has already been stated in the discussions. In true spread spectrum, if you were to look at the entire transmitted signal on an appropriate spectrum analyzer, you would see that the entire spectrum of the transmitted signal would be spread evenly throughout the bandwidth, regardless of input data. This is not necessarily true of an FSK / PSK signal in the short term. In the long term averaged over a period of time it may end up that way. Also of note, the frequency hopping characteristics of FSK/PSK modes are the result of the input data alone, not due to a pre-determined frequency pattern. Jose's documentation specifically mentioned NOT doing this for the reason of nobody would know what code to preset to be able to listen for CQ's, etc. Since Jose specifically chose not to implement this form of coding, to my way of thinking it also removes one of the specific defining points required to qualify as true spread spectrum. So the question remains is it really spread spectrum or not? Until that question is really answered, then any discussion of legality remains moot. Just because Jose declares it as spread spectrum does not make it that way. And unless a signal really is spread spectrum, then the well known laws against it's use on HF frequencies does not apply here. At the same time, if it does turn out that his definition IS correct and it IS spread spectrum rather than FSK or PSK (BPSK), then we now have numerous other common sound card based digital modes that become just as illegal because they operate the SSB transmitter in exactly the same way, by applying a variety of tones in different patterns to the audio input of it and them modulating it, which in turn causes the transmitter to output on a variety of different instantaneous frequencies based on that input data. The question of If we run RTTY with 850 Hz shift like we did in the old days, has that turned into spread spectrum? is a very valid question indeed ... John KE5HAM --- In digitalradio@yahoogroups.com, jhaynesatalumni jhhay...@... wrote: --- In digitalradio@yahoogroups.com, John ke5ham3@ wrote: Thanks Skip, Unfortunately, this really does not get to the crux of my question(s). I understand how an SSB transmitter works, but that is not really what I am after. What I am driving at is if like this. If I use DM780 to run some version of digital mode via an SSB transceiver, it uses a tone or series of tone modulation/shifting to create the output of the transmitter, and not one single mode is called spread spectrum output, but is called FSK or PSK, etc. Now, we get into the aforementioned discussion regarding ROS, and suddenly, still via the microphone input of the same transmitter, those shifted frequencies are now called spread spectrum instead. I am having a great deal of difficulty understanding, other than the author happened to call his scheme spread spectrum in his technical documentation. That's a good question. If we run RTTY with 850 Hz shift like we did in the old days, has that turned into spread spectrum?
RE: [digitalradio] Re: A new Mode !
Hi Jose Any indication when selectable soundcards will become a reality? So far unable to try ROS out here, as I use multiple soundcards - all digital operation through a non-default card. I have too much set up to want to mess with that!!! 73 de BARRY MURRELL ZS2EZ KF26ta - Port Elizabeth, South Africa Member : SARL - ARRL EPC#0558 DMC#1690 OMC#010 WCC#030 DXCC(mixed)#41,146 DXCC(RTTY)#1,916 DXCC(phone)#34,990 DXCC(CW)#11,714 DXCC 20m,17m,15m WAS(RTTY)#538 WAZ(RTTY)#185 WAE-I(mixed)#72 WAZS(mixed)#214 AAA#1569 AS ZR6DXB: VUCC(50MHZ)#1,334 UKSMG WAE(Silver)#75 UKSMG AFRICA#22 WAC (Satellite) Website : www.zs2ez.co.za http://www.zs2ez.co.za/ _ From: digitalradio@yahoogroups.com [mailto:digitalra...@yahoogroups.com] On Behalf Of nietorosdj Sent: 19 February 2010 02:50 PM To: digitalradio@yahoogroups.com Subject: [digitalradio] Re: A new Mode ! Hi, With the New Version 1.6.2 you can select from COM1 to COM6. For the future versions, i will make soundcard selectable, no problem. Thank you all for testing ROS. I hear your suggestions. --- In digitalradio@ mailto:digitalradio%40yahoogroups.com yahoogroups.com, Dave Ackrill dave.g0...@... wrote: nietorosdj wrote: Hi, tomorrow i will change PTT from COM1 to COM6, but i dont know if it'll run. Does any one know if it is possible to make the soundcard selectable and increase the options for the COM port? I use a US Interface Navigator, and computer control is on COM3 with PTT on COM4. so the switch that allows just COM1 or 2 isn't much use to me and I don't really like having to make the soundcard that I use for digital modes the Windows default either. Thanks - Dave (G0DJA) No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.5.435 / Virus Database: 271.1.1/2694 - Release Date: 02/18/10 19:34:00
