Re: [digitalradio] Re: Report on RFSM2400 vs. OFDM
Cesco, This is ridiculous. In no way did we trash your free mode! And please be aware that RFSM2400 is the same price as EasyPal ... free in terms of monetary cost. If you look at the results dispassionately, you will see that the SSTV mode did quite well considering it must have been on the edge of the minimum conditions. The kind of conditions are often found on HF. You might clear up one question that I have and that is if I have an image that is larger than 20K and I attempt to send it with the software, it appears to allow for adjustment of the actual size (compression). And a default seems to be 20K in 94 seconds. Is this correct? Now if I was able to get a substantial fraction (1/6) of that through in only 94 seconds, does that mean that over 3000 bytes were moved in that amount of time? If so, that is a higher throughput than the RFSM2400 program. I realize that it is not operating with immediate ARQ, but if you take that into account, it does not seem to be that different. JT65 can not be compared to PSK31 because it has no real throughput. What we are trying to do is compare relative speeds during the same conditions. Those kinds of real world tests seem the most important for actual ham use. The actual speed of around 300 bytes per minute, even if not all that fast, is faster than most other sound card modes at that signal to noise data point. Remember, cesco, we were using images as a surrogate for text data because we can not legally send text data in the voice/image portions of the bands. If we had an important 28K document to send, 12 minutes would be completely acceptable as long as we can guarantee that it will go through error free and had no other way to move the message. In terms of S/N, if you have an average reading of say, -89 dBm with the background noise and then you receive a signal at -76 dBm, are you saying that this relationship has no association with S/N? 73, Rick, KV9U cesco12342000 wrote: >> How is what we tested somehow flawed in your mind? >> > > Compare it to testing psk31 against jt65 at snr's of -20db. > psk31 wont work, jt65 will work. Flawed test. > > Your report of easypal only getting 1/6 of transmission is a clear > indication that conditions or setup were not adequate. I could not even > find what mode or qam type you were using. Flawed test. > > This is no weak signal mode. This mode is NOT automatic and needs quite > some dedication. Comparing this (probably in default config) with an > automatic mode is ... > > >> I do admit that I >> have done some calibration of my ICOM 756 Pro 2 S-meter and can give you >> at least some relative comparisons of dBm levels. >> > > S-meter and SNR have nothing in common. > > > What does enrage me is the trashing of a well established free mode with > the goal to hype up of an expensive software, which, you failed to > mention, proved to be unusable for sstv in your own test (12 min for a > 28kb picture is not acceptable). > > > > > > Announce your digital presence via our Interactive Sked Page at > http://www.obriensweb.com/sked > > > DRCC contest info : http://www.obriensweb.com/drcc.htm > > Yahoo! Groups Links > > > > > > >
Re: [digitalradio] Re: Report on RFSM2400 vs. OFDM
cesco, How is what we tested somehow flawed in your mind? Lets keep a positive outlook on those few (very, very few) hams who are willing to give some reports on their experiences with these new modes and even how they compare. I wish we had time for additional comparisons to some of the other modes. Hopefully other hams will also test these types of software to see how they work and how they compare. Even if their experiences are better or worse that ours.It is only when you have many data points in the data set that you start to get a good feel for these products. When we attempted to use this software we had no idea of what the SNR might be that evening. Most hams don't have very accurate ways to measure dBm levels based on their S-meters readings. I do admit that I have done some calibration of my ICOM 756 Pro 2 S-meter and can give you at least some relative comparisons of dBm levels. I have not been too sure about the software itself reporting accurately, but it certainly can help in giving some kind of estimate. I did not record the S-meter readings so I can not tell you now what the dBm levels were between noise and signal but it seemed about right based upon many years of experience. In the future I will try and do that and give relative dBm levels as that information may be useful in correlating to the software claim of S/N. The software indicated that we were in the 5 to 10 dB S/N range. What more could you want for a test of this type? Almost perfect, being right on the edge. The EasyPal software was able to work about where you would expect it to work. Not that I am an expect user, since most of my experience has been monitoring the 7173 group here in the midwestern U.S. And occasionally talking with Dave, KB4YZ. Remember that my interest is in how well can these modes work down into the worst conditions. Not how well they can work with +25 dB S/N levels that rarely happen with modest power levels and antennas under real world HF conditions. As far as RFSM2400, I don't think Andy and I had any preconceived ideas of how well the software would work ... or not work. That is why we tested it. Almost no one else has been willing to do so and/or report on it. The information that I have found on the "numbers" with many different waveforms used in these STANAG type modems are not based upon real world tests. They are almost all based on computer simulations. While that is useful initially for some comparisons of the modems, it is my firm view that you need to actually use them in the harsh HF environment to see what kind of results actually get. One could argue that the relatively low throughput of the RFSM2400 modem at the 5 to 10 dB S/N level was somewhat disappointing. Since we don't have much else that can work at that ARQ speed we discovered our test, in relative terms it did not seem too bad. And unlike other sound card modems, it can scale upward. I don't think it can scale downward a whole lot more as I think we were close to the edge of its capability. 73, Rick, KV9U cesco12342000 wrote: > Unluckily i have to say that this comparison is quite flawed... > > using easypal which needs minimum 6db SNR in the lowest setting in > conditions of less than 4db snr (1/6 throghput you say) is not a good > idea. Comparing that to a mode which can adapt to lower snr's is BS at > best. > > Your invited to repeat the test after having learned how to use easypal, > and use it in suitable conditions. There are lots of experienced d-sstvers > to get help from. > > > > > > Announce your digital presence via our Interactive Sked Page at > http://www.obriensweb.com/sked > > > DRCC contest info : http://www.obriensweb.com/drcc.htm > > Yahoo! Groups Links > > > > > > >
Re: [digitalradio] Re: Report on RFSM2400 vs. OFDM
I was in a similar boat Rick. Still have the P38 card sitting around somewhere, I found the instruction book as well the other day. B-) 73, John de VK2XGJ One of the reasons politicians try so hard to get themselves re-elected, because they couldn't live under the laws that they have passed! - Original Message - From: "Rick" <[EMAIL PROTECTED]> To: Sent: Monday, January 28, 2008 2:26 PM Subject: Re: [digitalradio] Re: Report on RFSM2400 vs. OFDM > It is ironic you should mention the P38, Les. > > Quite some years ago I was one of the early adopters of new technology. > Not usually the bleeding edge, but close to it. Tried a number of boxes, > including the Kantronics UTU, plug in card for Pactor for the C-64 > computer, AEA CP-1 with BMK Multi (early non Pactor version for around > $100 for DOS). > > Then I had to make the big decision on which modes were going to be the > future winners, particularly Clover II or Pactor. The AEA PK2232 and > similar costly modems became available. Pactor and Clover II had the > support from the Winlink BBS system and the RTTY Digital Journal group. > Specialized software such as Peter Schulze TY1PS's clever Windows based > Clover II Express software became available that did something that was > a first ... it would automatically send a thumbnail picture to other > stations equipped with this software. However, the legal aspect remained > questionable for us in the U.S. (Perhaps it was only because of Mark > Millers past petition that the FCC finally corrected this in very recent > time). Today it would be close to impossible for Peter to sell this kind > of software. Peter also sent perhaps the first digitized ham message > that included a recorded song. Another interesting issue since some > comments at the time seemed to suggest this might be legal here in the > U.S. but I suspect further review made it not so. > > I bought the P38 for my (at the time) fairly advanced 286 IBM computer > (ISA architecture bus and VGA graphics) and it never worked properly on > Pactor. Even after claims by HAL that it would be corrected. They just > could not get the programming right. It would connect with a Pactor > station and then drop the link. Completely useless product for Pactor. > > Even when having Clover II QSO's with Ray Petit, W7GHM, the inventor of > several early digital modes (Coherent CW, Clover, and then Clover II) we > had a difficult time maintaining much data throughput between our > locations with our mediocre antennas. Eventually, I returned the > pathetic modem to HAL but had to pay a restocking fee. I made the > decision at that point to abandon hardware modems and I am very > fortunate that I did. > > It was not until the sound card modes became popular that I returned to > digital modes again. And what a refreshing change it has been. And it is > constantly getting better with 2007 as the big year of change with ARQ > sound card modes becoming available. > > I would expect a number of other OT group members have had similar > experiences. > > 73, > > Rick, KV9U > > > Leskep wrote: >> Rick >> Doesnt only apply to software - I have already been down that same path >> with the P38 modem - got one going cheap if anyone wants it >> Les VK2DSG >> > > > > Announce your digital presence via our Interactive Sked Page at > http://www.obriensweb.com/sked > > > DRCC contest info : http://www.obriensweb.com/drcc.htm > > Yahoo! Groups Links > > > > > > -- > No virus found in this incoming message. > Checked by AVG Free Edition. > Version: 7.5.516 / Virus Database: 269.19.13/1246 - Release Date: > 1/27/2008 6:39 PM > >
Re: [digitalradio] Re: Report on RFSM2400 vs. OFDM
It is ironic you should mention the P38, Les. Quite some years ago I was one of the early adopters of new technology. Not usually the bleeding edge, but close to it. Tried a number of boxes, including the Kantronics UTU, plug in card for Pactor for the C-64 computer, AEA CP-1 with BMK Multi (early non Pactor version for around $100 for DOS). Then I had to make the big decision on which modes were going to be the future winners, particularly Clover II or Pactor. The AEA PK2232 and similar costly modems became available. Pactor and Clover II had the support from the Winlink BBS system and the RTTY Digital Journal group. Specialized software such as Peter Schulze TY1PS's clever Windows based Clover II Express software became available that did something that was a first ... it would automatically send a thumbnail picture to other stations equipped with this software. However, the legal aspect remained questionable for us in the U.S. (Perhaps it was only because of Mark Millers past petition that the FCC finally corrected this in very recent time). Today it would be close to impossible for Peter to sell this kind of software. Peter also sent perhaps the first digitized ham message that included a recorded song. Another interesting issue since some comments at the time seemed to suggest this might be legal here in the U.S. but I suspect further review made it not so. I bought the P38 for my (at the time) fairly advanced 286 IBM computer (ISA architecture bus and VGA graphics) and it never worked properly on Pactor. Even after claims by HAL that it would be corrected. They just could not get the programming right. It would connect with a Pactor station and then drop the link. Completely useless product for Pactor. Even when having Clover II QSO's with Ray Petit, W7GHM, the inventor of several early digital modes (Coherent CW, Clover, and then Clover II) we had a difficult time maintaining much data throughput between our locations with our mediocre antennas. Eventually, I returned the pathetic modem to HAL but had to pay a restocking fee. I made the decision at that point to abandon hardware modems and I am very fortunate that I did. It was not until the sound card modes became popular that I returned to digital modes again. And what a refreshing change it has been. And it is constantly getting better with 2007 as the big year of change with ARQ sound card modes becoming available. I would expect a number of other OT group members have had similar experiences. 73, Rick, KV9U Leskep wrote: > Rick > Doesnt only apply to software - I have already been down that same path > with the P38 modem - got one going cheap if anyone wants it > Les VK2DSG >
Re: [digitalradio] Re: Report on RFSM2400 vs. OFDM
Rick Doesnt only apply to software - I have already been down that same path with the P38 modem - got one going cheap if anyone wants it Les VK2DSG From: Rick Sent: Monday, January 28, 2008 1:52 AM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Re: Report on RFSM2400 vs. OFDM I'm not sure what Les wrote about the cost of the product, but my understanding was that there was a temporary $60 price associated with RFSM8000 from the normal price. The question is: who will buy it at any price? If you have seen what has happened to other developers who tried to charge for their products, some of them having excellent value, they simply failed to find a market. In fact, I would be hard pressed to come up with any new ham software products in recent time that have taken off and been purchased by many hams. Consider programs such as the paperchaser log which was a niche logging program. After a few years the author discontinued the product because he only had a few buyers. I sure would not want to have been one of those buyers. But I nearly was as it looked like a very good program! Imagine someone buying such a program that t is now free, but worse, it is no longer been developed or supported. I suspect the same thing happened with the emergency group that thought they were going to be able to charge $50 per seat for their emergency program. I don't think it succeeded. But others have gone on to develop similar programs at no charge. But even those programs are not heavily used either. There is a limited amount of mindshare with all this technology and many of us are on overload as it is. (Not only for ham programs, but the hundreds of competing programs and even operating systems which are open source or at least free as in beer). I am now using an astronomy program that is completely free and that is as good as what you used to have to pay $50 to $100 for just a few years ago. The Open Office Suite has made it possible to avoid buying the MS Office Suite saving at least $500. I do not consider this a bad thing at all. It makes more software available to more people and equalizes the power to everyone and not just those with a lot of money. Where the RFSM8000 type of product seems to have the greatest value is in the commercial market. Assuming that it can compete with multi thousand dollar STANAG modems, it should be an excellent buy for those who use this technology. I know that I probably speak for a majority of hams who wish them well. As I have said many times, what I am looking for is a program that provides ARQ chat that can operate under the worst possible conditions and can also scale if conditions warrant so that I can send any data that I am interested in sending and is legal to use in my country. The technology has been invented to do slow, medium, and fast speeds (1000 wpm text data) depending upon the conditions, but no one has been able to put this together in a simple to use package that will appeal to the mainstream digital ham. I believe the best approach, and I see some are talking about this lately, are programs that are modular and you can bolt on various parts and not have to reinvent the wheel over and over with each new mode. 73, Rick, KV9U dmitry_d2d wrote: > Hi Les, Rick and all. > > About prices of RFSM-8000. > I'm sorry, but Les was wrote incorrect information. > In January, we offer special low prices. > Price of FULL Featured (with Mail-Server) version is 60 USD (only for > HAMs). > Mail-Client version is unavailable. > And, we think, this action (special low prices for HAMs) will be > continued - in February and more. > Please, see our web-page for last correct information: > http://rfsm2400.radioscanner.ru > > 73, > Dmitry (RFSM-IDE Group). > > > > Announce your digital presence via our Interactive Sked Page at > http://www.obriensweb.com/sked > > > DRCC contest info : http://www.obriensweb.com/drcc.htm > > Yahoo! Groups Links > > > > > > >
Re: [digitalradio] Re: Report on RFSM2400 vs. OFDM
I'm not sure what Les wrote about the cost of the product, but my understanding was that there was a temporary $60 price associated with RFSM8000 from the normal price. The question is: who will buy it at any price? If you have seen what has happened to other developers who tried to charge for their products, some of them having excellent value, they simply failed to find a market. In fact, I would be hard pressed to come up with any new ham software products in recent time that have taken off and been purchased by many hams. Consider programs such as the paperchaser log which was a niche logging program. After a few years the author discontinued the product because he only had a few buyers. I sure would not want to have been one of those buyers. But I nearly was as it looked like a very good program! Imagine someone buying such a program that t is now free, but worse, it is no longer been developed or supported. I suspect the same thing happened with the emergency group that thought they were going to be able to charge $50 per seat for their emergency program. I don't think it succeeded. But others have gone on to develop similar programs at no charge. But even those programs are not heavily used either. There is a limited amount of mindshare with all this technology and many of us are on overload as it is. (Not only for ham programs, but the hundreds of competing programs and even operating systems which are open source or at least free as in beer). I am now using an astronomy program that is completely free and that is as good as what you used to have to pay $50 to $100 for just a few years ago. The Open Office Suite has made it possible to avoid buying the MS Office Suite saving at least $500. I do not consider this a bad thing at all. It makes more software available to more people and equalizes the power to everyone and not just those with a lot of money. Where the RFSM8000 type of product seems to have the greatest value is in the commercial market. Assuming that it can compete with multi thousand dollar STANAG modems, it should be an excellent buy for those who use this technology. I know that I probably speak for a majority of hams who wish them well. As I have said many times, what I am looking for is a program that provides ARQ chat that can operate under the worst possible conditions and can also scale if conditions warrant so that I can send any data that I am interested in sending and is legal to use in my country. The technology has been invented to do slow, medium, and fast speeds (1000 wpm text data) depending upon the conditions, but no one has been able to put this together in a simple to use package that will appeal to the mainstream digital ham. I believe the best approach, and I see some are talking about this lately, are programs that are modular and you can bolt on various parts and not have to reinvent the wheel over and over with each new mode. 73, Rick, KV9U dmitry_d2d wrote: > Hi Les, Rick and all. > > About prices of RFSM-8000. > I'm sorry, but Les was wrote incorrect information. > In January, we offer special low prices. > Price of FULL Featured (with Mail-Server) version is 60 USD (only for > HAMs). > Mail-Client version is unavailable. > And, we think, this action (special low prices for HAMs) will be > continued - in February and more. > Please, see our web-page for last correct information: > http://rfsm2400.radioscanner.ru > > 73, > Dmitry (RFSM-IDE Group). > > > > Announce your digital presence via our Interactive Sked Page at > http://www.obriensweb.com/sked > > > DRCC contest info : http://www.obriensweb.com/drcc.htm > > Yahoo! Groups Links > > > > > > >
Re: [digitalradio] Re: Report on RFSM2400 vs. OFDM
Hi Dmitry My apologies for the wrong information Les VK2DSG From: dmitry_d2d Sent: Sunday, January 27, 2008 5:40 PM To: digitalradio@yahoogroups.com Subject: [digitalradio] Re: Report on RFSM2400 vs. OFDM Hi Les, Rick and all. About prices of RFSM-8000. I'm sorry, but Les was wrote incorrect information. In January, we offer special low prices. Price of FULL Featured (with Mail-Server) version is 60 USD (only for HAMs). Mail-Client version is unavailable. And, we think, this action (special low prices for HAMs) will be continued - in February and more. Please, see our web-page for last correct information: http://rfsm2400.radioscanner.ru 73, Dmitry (RFSM-IDE Group).
