GM Rick, Several months ago I did some testing on HF with RFSM2400. We were able to transfer 4000 character files in ~40 secs. This is similar to what Les was able to achieve. Conditions were excellent then. Recently I was able to test with Chuck, AA5J on VHF and this time the throughput was similar to your numbers even though we had good signal conditions. I realize this does not clarify the throughput ability but it does show that it can achieve high speeds under certain conditions. I still do not know how deep in the mud it will go and still work.
Regarding the tuning; we were able to achieve connects by tuning the transceiver dial to the point where the initial sync burst lined up with the red line in the 'Tuning to Signal' window during a connect. We tested the 3 khz wide mode and then the 2.4 khz mode. We were able to get more throughput on the narrower mode. I think this just says our SSB filters were not handling the wider mode well. No doubt we could have changed to wider filters (or FM mode) and gotten better results. I think the developers were up front that they would eventually charge for the package. I was surprised by the price too. It could be worth it if the FCC allows the higher rate, and if many people are using the software. There may be some competition if the ALE folks get something in place that is easy to use. I would love to see this mode in NBEMS for file transfer operations. Howard K5HB ----- Original Message ---- From: Rick <[EMAIL PROTECTED]> To: [email protected] Sent: Saturday, January 26, 2008 9:16:50 AM Subject: Re: [digitalradio] Report on RFSM2400 vs. OFDM Hi Les, This was the first time I could get anyone to even try the mode as I have been attempting that for some time. From what I can tell, you need to be connected in order to do much with the mode to really do any kind of testing other than perhaps calling a "dummy" station. In regard to your questions: 1. I may have an older version, but I don't find a sound card offset in the Options. My sound card has been extremely accurate (Sound Blaster Live!) when tested with other programs and can be within a Hz or two. 2. The sampling rate is set to 48000. 3. My main interest is having very robust modes that work at the highest possible speed under the most difficult conditions. I have spent considerable time sifting through the materials found on the internet on STANAG modems (I will use the term STANAG as a short form of what is a large number of different modems) and from the published information, the throughput drops off rapidly when you go below zero dB S/N. The throughput last night did not really quite meet those expectations, but this may be due to other factors, such as insufficient computing power or the software modem not being able to match the multi thousand dollar STANAG modems. At least that seems reasonable to me, otherwise, why would governments spend the astronomical amounts of money for such modems? Having said that, my inside information from those who actually use these modems for government/military use, find that they don't work quite as impressively as the advertising might suggest. But at least we are getting a taste of what we can expect from this kind of technology. Perhaps others may have more information to compare the relative performance of the software modems of various types? Also, have you tried these modems on VHF? Here in the U.S. we can use them above 50 MHz, and I think we can mix and match modes there as well. I have not found anyone to test this with my mediocre 6 meter antenna, but I just realized that this may actual work dramatically faster than NBEMS. If Skip, KH6TY is reading this, perhaps he can comment. 73, Rick, KV9U Leskep wrote: > Hi Rick > Regarding RFSM2400/8000 > I wonder if you both set up your sound card offsets in the program > Options/Hardware > This program does require a fairly correct sample rate setting on > both TX and RX to achieve full speed > On tests done here on a fairly quiet band on 40m and 80m > before just before sunset there has been no problem to achieve > speeds as the records show below > > BTW Our testing has been done with RFSM8000 which has the ability > to work at 6666 bits per second > > The times shown below are in the afternoons on a relatively quiet band > and over a distance of 250 klm for VK2KNC and 400 klm for VK2JN > > > > > 'VK2KNC' accept MAIL-requests. - 4/11/2007 - 3:09:32 PM > Receiving file '0101vlrg.jpg' , compressed size 87920 bytes, from > 'VK2KNC'... - 4/11/2007 - 3:10:01 PM > File '0101vlrg.jpg' received succesfully, all time 406 sec, average > speed 1930 (1730) bits/sec - 4/11/2007 - 3:17:01 PM > Disconnected from 'VK2KNC' - 4/11/2007 - 3:17:15 PM > > Sending request for file 'stop7.jpg'. .. - 18/11/2007 - 3:33:46 PM > Receiving file 'stop7.jpg', compressed size 15840 bytes, from > 'VK2JN'... - 18/11/2007 - 3:33:59 PM > File 'stop7.jpg' received succesfully, all time 39 sec, average speed > 3240 (3231) bits/sec - 18/11/2007 - 3:34:53 PM > Sending request for file 'Recycle.jpg' ... - 18/11/2007 - 3:35:32 PM > Receiving file 'Recycle.jpg' , compressed size 43945 bytes, from > 'VK2JN'... - 18/11/2007 - 3:35:45 PM > File 'Recycle.jpg' received succesfully, all time 126 sec, average > speed 2779 (2777) bits/sec - 18/11/2007 - 3:38:07 PM > Disconnecting from 'VK2JN' - 18/11/2007 - 3:39:21 PM > > > > Sending request for file 'closeeyes5. jpg'... - 20/11/2007 - 4:02:27 PM > Receiving file 'closeeyes5. jpg', compressed size 75482 bytes, from > 'VK2JN'... - 20/11/2007 - 4:02:38 PM > File 'closeeyes5. jpg' received succesfully, all time 195 sec, average > speed 3095 (3089) bits/sec - 20/11/2007 - 4:06:09 PM > Disconnecting from 'VK2JN' - 20/11/2007 - 4:06:54 PM > > > Sending file 'Cycle24predictions .jpg', compressed size 65750 bytes > (real size 76145 bytes), to 'VK2KNC'... - 18/12/2007 - 1:49:17 PM > Connecting to POP3-server. .. - 18/12/2007 - 1:49:58 PM > Connected to POP3-server. .. - 18/12/2007 - 1:49:58 PM > Doing authentification. .. - 18/12/2007 - 1:49:58 PM > Checking incoming mail... - 18/12/2007 - 1:49:59 PM > POP3-server has 0 incoming mails. - 18/12/2007 - 1:49:59 PM > Stop checking incoming mail. - 18/12/2007 - 1:49:59 PM > > [I cut some server stuff out] > > Connecting to POP3-server. .. - 18/12/2007 - 1:54:00 PM > Connected to POP3-server. .. - 18/12/2007 - 1:54:00 PM > Doing authentification. .. - 18/12/2007 - 1:54:00 PM > Checking incoming mail... - 18/12/2007 - 1:54:00 PM > POP3-server has 0 incoming mails. - 18/12/2007 - 1:54:00 PM > Stop checking incoming mail. - 18/12/2007 - 1:54:00 PM > > File 'Cycle24predictions .jpg' sended succesfully, all time 05:08 > (mm:ss), average speed 1975 (1705) bits/sec - 18/12/2007 - 1:54:25 PM > > You might like to compare some of the above figures taken from the > sys_log.txt from RFSM8000 > > Les VK2DSG > > > <!-- #ygrp-mkp{ border:1px solid #d8d8d8;font-family:Arial;margin:14px 0px;padding:0px 14px;} #ygrp-mkp hr{ border:1px solid #d8d8d8;} #ygrp-mkp #hd{ color:#628c2a;font-size:85%;font-weight:bold;line-height:122%;margin:10px 0px;} #ygrp-mkp #ads{ margin-bottom:10px;} #ygrp-mkp .ad{ padding:0 0;} #ygrp-mkp .ad a{ color:#0000ff;text-decoration:none;} --> <!-- #ygrp-sponsor #ygrp-lc{ font-family:Arial;} #ygrp-sponsor #ygrp-lc #hd{ margin:10px 0px;font-weight:bold;font-size:78%;line-height:122%;} #ygrp-sponsor #ygrp-lc .ad{ margin-bottom:10px;padding:0 0;} --> <!-- #ygrp-mlmsg {font-size:13px;font-family:arial, helvetica, clean, sans-serif;} #ygrp-mlmsg table {font-size:inherit;font:100%;} #ygrp-mlmsg select, input, textarea {font:99% arial, helvetica, clean, sans-serif;} #ygrp-mlmsg pre, code {font:115% monospace;} #ygrp-mlmsg * {line-height:1.22em;} #ygrp-text{ font-family:Georgia; 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