[digitalradio] Re: 30m 2.8KHz wide digital signal QRM
Hi Les, I listened yesterday as I said I would but heard nothing of note except for some hash that was switching on off at regular intervals. I did a screen grab of the start of the tx, during the tx at the switch off.They are not much to look at,just horizontal shear,so I will not post them with this message but if anyone does want them I wil send them direct. 73 Alan G3VLQ
[digitalradio] Re: 30m 2.8KHz wide digital signal QRM
Hi Andy If you have a waterfall running vertically it would be a 30 sec bar across the screen about 2.8KHz wide. If the two stations were exchanging info there would be four 30 sec bars over a 2 minute period followed by a 1 minute break to the next exchange. The signal switched off sometime during the morning of the 24th. This morning there was another digital signal on the same frequency using a different mode, it switched off at 08:03utc and I've heard nothing since. Les G3VYZ --- In digitalradio@yahoogroups.com, Andrew O'Brien [EMAIL PROTECTED] wrote: Is this signal represented on a waterfall as three vertical lines, equally spaced? Andy K3UK
[digitalradio] Re: 30m 2.8KHz wide digital signal QRM
Hi Alan That does sound something similar, the signal switched off sometime on the morning of the 24th when I was out of the house. You may have seen my reply to Andy, but there was a signal on the same frequency this morning using a different mode which switched off at 08:03utc. Since then it's been very quiet on the band around 10.137 to 10.142MHz. Les G3VYZ --- In digitalradio@yahoogroups.com, merv0728 [EMAIL PROTECTED] wrote: Hi Les, I listened yesterday as I said I would but heard nothing of note except for some hash that was switching on off at regular intervals. I did a screen grab of the start of the tx, during the tx at the switch off.They are not much to look at,just horizontal shear,so I will not post them with this message but if anyone does want them I wil send them direct. 73 Alan G3VLQ
[digitalradio] CQ DRCC
I am on 14078.0 Feld Hell for the till 1230 calling CQ and looking for DRCC and FH numbers. Jim VA3HJ
[digitalradio] Comments on Communicational and Technology from CA
http://www.networkworld.com/community/node/20911 Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net
[digitalradio] DM780 and Google Earth
I am not sure if you have noticed it or not, but when using DM780 and the decoded digital mode text includes a URL, that URL is clickable. Click on it and DM780 opens up a browser and goes to the URL. Do other digital mode software provide this feature? I have not noticed it. This feature has some interesting capabilities. One is that you can reference a Google Earth URL . and it could send the station you are working on a tour of your neighbourhood while you are in QSO with them. Instead of a brag macro telling them about your QTH and shack. They can actually see your street and even your shack! I have not had time to really program this feature with a polished look, but here are a couple of quick examples. Press play tour button in Google Earth to begin the animated tour. http://www.obriensweb.com/k3ukqth.kmz http://www.obriensweb.com/house.kmz (G0DJA's house) I'm not 100% sure they will open with a click when decoded in DM780, have to find someone on the air to test. Since usual URL's with a .htm do, I assume a kmz will. The station you are working will need to have Google Earth installed to view the file/maps -- Andy K3UK www.obriensweb.com (QSL via N2RJ)
[digitalradio] RSS Feed
What happened to the RSS feed. It stopped working on 10/22, and the link is gone from the home page. Thanks for any help. 73... Jon W1MNK
[digitalradio] QEX Article on HF Digital Propagation
There is a great article in the QEX I just received (Nov/Dec 2007). The author is Daniel Crausaz HB9TPL in Switzerland. He reports on modeling and testing PSK, RTTY, Olivia, MFSK, DominoEx and Feld-Hell under various propagation conditions. I need to digest his work with respect to the OFDM proposal since the results indicate PSK may not be an optimal choice. Olivia works better under all the conditions tested. MFSK seems to be second. At first glance I would say this is because the transmission rate is so slow for Olivia at 2.5 character per second. I would find that painfully slow for even a chat mode. Interestingly, RTTY performs about the same under all the conditions tested. PSK either works well or just fails. It has problems in flutter conditions which seem to me be the conditions prevalent a lot of the time. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net
Re: [digitalradio] Re: CQ DRCC...
I don't think your messsage had to be approved, it may have been simply that Yahoo some times delays the email Andy. On 10/25/07, va3jno [EMAIL PROTECTED] wrote: --- In digitalradio@yahoogroups.com digitalradio%40yahoogroups.com, n6vl [EMAIL PROTECTED] wrote: Why can't the digitalradio reflector have a similar degree of activity discussing modes, bands, and where to collect numbers. I think this is what Andy hoped for. After he, issued the numbers, I haven't sent a single message about how to go about collecting numbers. Does this mean digital ops don't have the same enthusiasm as CW ops? I don't think so. Well, I posted a message titled CQ DRCC this morning saying I was on frequency until and looking for DRCC and FH numbers. Unfortunately, by the time the message was approved, the time had expired and I had gone to do work around the house. I guess I posted the message about the time that Andy was headed to work so he didn't see it in time to be of use. I have also in the past self-spotted on the W6RK data mode spots page and not had anyone come back to my CQs. Is there little interest in actually having QSOs in digital modes other than PSK, or am I simply not posting/spotting in the right places? Where would such activity be best? 73, Jim VA3HJ -- Andy K3UK www.obriensweb.com (QSL via N2RJ)
[digitalradio] Re: CQ DRCC...
--- In digitalradio@yahoogroups.com, Andrew O'Brien [EMAIL PROTECTED] wrote: I don't think your messsage had to be approved, it may have been simply that Yahoo some times delays the email Andy. I was wrong... Oct 25, 2007 7:58 pmva3jno Post status changed by molou99 w0jab Sorry, glad John found it and set things up for your future posts. Andy.
RE: [digitalradio] QEX Article on HF Digital Propagation
There is a great article in the QEX I just received (Nov/Dec 2007). Darn! I KNEW that as soon as I didn't renew my subscription, they'd publish an article that I'd want to read. I don't s'pose somebody wants to violate the copyright by scanning the article in and post it somewhere, huh?? Oh, never mind... forget that I asked that. de Peter K1PGV
Re: [digitalradio] Re: Need KAM Plus manual
At 02:13 PM 10/11/2007, n6vl wrote: I was successful after calling Kantronics. The tech support guy referred me to the mods.dk web site. I was able to get scanned PDFs for a small donation. 73, Steve N6VL Steve, I also have a KAM Plus with no manual. I would be eternally grateful if you would forward a copy of the PDF. Barring that, could you give me the URL to the mods.dk web site? 73, Chuck, AA5J
RE: [digitalradio] QEX Article on HF Digital Propagation
You might try emailing the author for a copy. I checked the QEX web page because they always feature an article. Unfortunately it was another article for this issue. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Peter G. Viscarola Sent: Thursday, October 25, 2007 4:06 PM To: digitalradio@yahoogroups.com Subject: RE: [digitalradio] QEX Article on HF Digital Propagation There is a great article in the QEX I just received (Nov/Dec 2007). Darn! I KNEW that as soon as I didn't renew my subscription, they'd publish an article that I'd want to read. I don't s'pose somebody wants to violate the copyright by scanning the article in and post it somewhere, huh?? Oh, never mind... forget that I asked that. de Peter K1PGV Announce your digital presence via our Interactive Sked Page at http://www.obriensweb.com/drsked/drsked.php Yahoo! Groups Links
Re: [digitalradio] Re: CQ DRCC...
I think that I have mentioned some of this before, but unless you have a club of some kind where interested hams join and buy in to a concept, a numbering system may not be something that many will gravitate toward. In terms of digital operation, we digital operators are an extreme minority of the total of ham communications and unlike CW and SSB, we have many modes that can not talk to each other so realistically most hams who are starting out are going to use the easiest mode that is generally available on all soundcard multimode digital software and that is PSK31. It is also much narrower than most other digital modes so it fulfills its proper place as a spectrum efficient mode for keyboarding. This is especially true if you do not have difficult ionospheric conditions. Since so many hams tend to operate PSK31, it has a critical mass much of the time on the HF bands and there are specific narrow watering holes where PSK31 is found. This is even true on bands that you might think were closed to propagation, e.g., 28.120 MHz which has surprised me many times. Since there are so many other S.C. digital modes, some of which are difficult to determine the mode, or with some of them, e.g., Olivia, you may know it is Olivia, but are not sure of the speed. (At least I am not always able to determine a given mode by sound and waterfall display.) Many of the newer modes were interesting to try out and there would be a flurry of activity, but for basic keyboarding, which is what most digital operators do, PSK31 works well enough much of the time. Personally, I like MFSK16 as it is still moderately narrow and it was added to Ham Radio Deluxe/Digital Master 780 along with other modes. I also kind of like DEX (Domino EX), especially with FEC, but DEX 11 and FEC is not available on my version of DM780. Some of the digital modes are too slow for me, 30 -40 wpm, don't work into the noise all that well, and may not handle multipath all that well. etc. What might work is to make a contact on PSK31 and then ask the station if they want to try some other modes. I would much rather be on almost any mode other than PSK 31. Of course you would usually want to move up a kHz or two depending upon activity. I often place my dial frequency a kHz or two above the point that most PSK31 operators would select and then put my center frequency at 1500 Hz since that is optimized for my rig. Although I listen a lot more than I call CQ, I have been able to find operators with non PSK31 modes, by calling CQ in the mode of my choice. It may help to use the FAX ID in the waterfall. Have you tried that? 73, Rick, KV9U va3jno wrote: Well, I posted a message titled CQ DRCC this morning saying I was on frequency until and looking for DRCC and FH numbers. Unfortunately, by the time the message was approved, the time had expired and I had gone to do work around the house. I guess I posted the message about the time that Andy was headed to work so he didn't see it in time to be of use. I have also in the past self-spotted on the W6RK data mode spots page and not had anyone come back to my CQs. Is there little interest in actually having QSOs in digital modes other than PSK, or am I simply not posting/spotting in the right places? Where would such activity be best? 73, Jim VA3HJ
[digitalradio] RE: QEX Article on HF Digital Propagation
After a comment off list from Demeter I checked the Pactor specifications. It uses DBPSK or DQPSK. Why do the reports about Pactor indicate it is more robust than the QEX article would indicate? Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: Rud Merriam [mailto:[EMAIL PROTECTED] Sent: Thursday, October 25, 2007 1:10 PM To: 'digitalradio@yahoogroups.com' Subject: QEX Article on HF Digital Propagation There is a great article in the QEX I just received (Nov/Dec 2007). The author is Daniel Crausaz HB9TPL in Switzerland. He reports on modeling and testing PSK, RTTY, Olivia, MFSK, DominoEx and Feld-Hell under various propagation conditions. I need to digest his work with respect to the OFDM proposal since the results indicate PSK may not be an optimal choice. Olivia works better under all the conditions tested. MFSK seems to be second. At first glance I would say this is because the transmission rate is so slow for Olivia at 2.5 character per second. I would find that painfully slow for even a chat mode. Interestingly, RTTY performs about the same under all the conditions tested. PSK either works well or just fails. It has problems in flutter conditions which seem to me be the conditions prevalent a lot of the time. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net
Re: [digitalradio] QEX Article on HF Digital Propagation
Dan, HB9TPL, has put a summary of this data on his web page http://www.hb9tpl.ch/5009.html and while you are at it, take a look at his QTH! Perhaps the most spectacular station location I have seen. (even if he does have to do some hiking in during the winter time. Wes, WZ7I On 10/25/07, Rud Merriam [EMAIL PROTECTED] wrote: You might try emailing the author for a copy. I checked the QEX web page because they always feature an article. Unfortunately it was another article for this issue.
Re: [digitalradio] Comments on Communicational and Technology from CA
Rud Merriam wrote: http://www.networkworld.com/community/node/20911 Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net I am a great beliver is using WiFi under Part 97 as well as Part 15. When I need that extra little boost of power I opt for operation under Part 97 is using the system for myself. However, if the power limit of Part 15 is sufficient and non-hams need to use WiFi, I can go that way also. I would hope that as many amateur radio operators as possible will set up for providing WiFi at or near the MAX radiated power level as possible so that we may be of service to the public. Also, I hope that many hams will remote their rigs (both HF and V/UHF) so that distributed communications can be had. I know a couple of individuals who run PSK modes on their home rigs from any Internet connectivity...a really nice touch. 73, Walt/K5YFW
[digitalradio] What DXCC mode is AMTOR?
Got my DXCC the other day and was surprised to see an AMTOR QSO registered as CW. Is this normal or a simple error? Tnx es 73 Dave KB3MOW
Re: [digitalradio] What DXCC mode is AMTOR?
I would have to say an error. But just a guess on my part. At 06:21 PM 10/25/2007, you wrote: Got my DXCC the other day and was surprised to see an AMTOR QSO registered as CW. Is this normal or a simple error? Tnx es 73 Dave KB3MOW
Re: [digitalradio] What DXCC mode is AMTOR?
I'd think AMTOR would be included under RTTY. 73 Buddy WB4M - Original Message - From: Dave [EMAIL PROTECTED] To: digitalradio@yahoogroups.com Sent: Thursday, October 25, 2007 7:21 PM Subject: [digitalradio] What DXCC mode is AMTOR? Got my DXCC the other day and was surprised to see an AMTOR QSO registered as CW. Is this normal or a simple error? Tnx es 73 Dave KB3MOW Announce your digital presence via our Interactive Sked Page at http://www.obriensweb.com/drsked/drsked.php Yahoo! Groups Links
Re: [digitalradio] What DXCC mode is AMTOR?
That would be an error. AMTOR is a digital mode and is equivalent to RTTY. http://www.arrl.org/tis/info/digital.html 73 de Bob - KØRC in MN - Original Message - From: Dave To: digitalradio@yahoogroups.com Sent: Thursday, October 25, 2007 6:21 PM Subject: [digitalradio] What DXCC mode is AMTOR? Got my DXCC the other day and was surprised to see an AMTOR QSO registered as CW. Is this normal or a simple error? Tnx es 73 Dave KB3MOW
Re: [digitalradio] QEX Article on HF Digital Propagation
The best mode to use depends on how much data you want to transmit in a given bandwidth. Moving lots of data in a small bandwidth requires sending one or more bits per subcarrier. Otherwise, you can spread one bit out over multiple subcarriers. For any given user data rate, increasing the bandwidth decreases the required signal to noise ratio. MFSK uses multiple subcarriers but activates only one at a time, encoding 3 bits onto 8 subcarriers, 4 bits onto 16 subcarriers, etc. This is just N-ary RTTY. Multiple subcarriers can be used simultaneously with error-correcting codes like the Walsh function (a Hadamard matrix) which maps 8-bits into 128 subcarriers, 7 bits into 64 subcarriers, 6 bits into 64 subcarriers, etc. This is actually OFDM, but with rate 1/16, 7/64 or 3/32 error-correcting codes. With low SNRs, the hard part is achieving time and frequency synchronization. It seems to me that the ideal HF modem would use OFDM that occupyies a constant bandwidth using a subcarrier spacing that suits the Doppler spread and multipath spread for the current path and changes the code rate to suit the available SNR. 73, John KD6OZH - Original Message - From: Rud Merriam To: digitalradio@yahoogroups.com Sent: Thursday, October 25, 2007 18:10 UTC Subject: [digitalradio] QEX Article on HF Digital Propagation There is a great article in the QEX I just received (Nov/Dec 2007). The author is Daniel Crausaz HB9TPL in Switzerland. He reports on modeling and testing PSK, RTTY, Olivia, MFSK, DominoEx and Feld-Hell under various propagation conditions. I need to digest his work with respect to the OFDM proposal since the results indicate PSK may not be an optimal choice. Olivia works better under all the conditions tested. MFSK seems to be second. At first glance I would say this is because the transmission rate is so slow for Olivia at 2.5 character per second. I would find that painfully slow for even a chat mode. Interestingly, RTTY performs about the same under all the conditions tested. PSK either works well or just fails. It has problems in flutter conditions which seem to me be the conditions prevalent a lot of the time. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net
Re: [digitalradio] RE: QEX Article on HF Digital Propagation
Rud Merriam wrote: After a comment off list from Demeter I checked the Pactor specifications. It uses DBPSK or DQPSK. Why do the reports about Pactor indicate it is more robust than the QEX article would indicate? Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net Rud, If you go back to the DCC presentation of KN6KB of a few years back on his new software modem...he measured the robustness of Pactor, MT63 and several other modes and Pactor wasn't that much more robust than MT63 at a -5 dB SNR. If I invested a $K Buck or so in Pactor III and WinLink, I'd claim it was the best thing since sliced bread...woudln't you? 73, Wa;t/K5YFW
Re: [digitalradio] RE: QEX Article on HF Digital Propagation
One other comment. I have said before on this list that I have seen and used to have data produced by SouthWest Research Institute here in San Antonio that shows the maximim probable data capability of a single PSK signal. This study was done for the U.S. Government in research to find the best robust, medium throughput mode for a nation command alert system os some sort. I suspect it had something to do with always being able to keep the President informed under the most trying conditions with some sort of broadcast system. The upshot of all this as a limited discussion of a number of hams that were at the reporting session that the current MIL-STD modems could be improved on but that to obtain the desired throughput you would need more than the bandwidth associated with normal SSB transmitters. While amateur radio main not want a 4 or 5 KHz signal and the throughput that the government wanted, I think that a compromise bandwidth, something between that of PSK31 and perhaps 1 KHz with OFDM signal might be adequate for hams use on HF. As many have said before...if you REALLY want/need 100 error free copy, you are going to need an ARQ function and FEC. The trick is finding just how much of you signal you are going to give to FEC vs user data and how hard do you want to enforce ARQ. 73, Walt/K5YFW Walt DuBose wrote: Rud Merriam wrote: After a comment off list from Demeter I checked the Pactor specifications. It uses DBPSK or DQPSK. Why do the reports about Pactor indicate it is more robust than the QEX article would indicate? Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net Rud, If you go back to the DCC presentation of KN6KB of a few years back on his new software modem...he measured the robustness of Pactor, MT63 and several other modes and Pactor wasn't that much more robust than MT63 at a -5 dB SNR. If I invested a $K Buck or so in Pactor III and WinLink, I'd claim it was the best thing since sliced bread...woudln't you? 73, Wa;t/K5YFW
RE: [digitalradio] RE: QEX Article on HF Digital Propagation
I should have been more clear in my comment. The QEX article shows that PSK31 is terrible under conditions that induce phase changes. The MFSK16 and Olivia did much better. Even RTTY worked well under those conditions. PSK31 failed, bad copy even under good SNR, with 3 ms multipath and 10 Hz Doppler. It did not do well with 2 ms multipath and 1 Hz Doppler. Since Pactor uses PSK I wondered if it would similarly fail as shown by the PSK31 results. I suspect that it handles Doppler better through frequency tracking algorithms. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Walt DuBose Sent: Thursday, October 25, 2007 9:38 PM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] RE: QEX Article on HF Digital Propagation Rud Merriam wrote: After a comment off list from Demeter I checked the Pactor specifications. It uses DBPSK or DQPSK. Why do the reports about Pactor indicate it is more robust than the QEX article would indicate? Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net Rud, If you go back to the DCC presentation of KN6KB of a few years back on his new software modem...he measured the robustness of Pactor, MT63 and several other modes and Pactor wasn't that much more robust than MT63 at a -5 dB SNR. If I invested a $K Buck or so in Pactor III and WinLink, I'd claim it was the best thing since sliced bread...woudln't you? 73, Wa;t/K5YFW Announce your digital presence via our Interactive Sked Page at http://www.obriensweb.com/drsked/drsked.php Yahoo! Groups Links
RE: [digitalradio] RE: QEX Article on HF Digital Propagation
Any chance of you locating that study information? I would like to use every technique possible to maximize the data in a 500 Hz signal. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Walt DuBose Sent: Thursday, October 25, 2007 9:51 PM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] RE: QEX Article on HF Digital Propagation One other comment. I have said before on this list that I have seen and used to have data produced by SouthWest Research Institute here in San Antonio that shows the maximim probable data capability of a single PSK signal. This study was done for the U.S. Government in research to find the best robust, medium throughput mode for a nation command alert system os some sort. I suspect it had something to do with always being able to keep the President informed under the most trying conditions with some sort of broadcast system. The upshot of all this as a limited discussion of a number of hams that were at the reporting session that the current MIL-STD modems could be improved on but that to obtain the desired throughput you would need more than the bandwidth associated with normal SSB transmitters. While amateur radio main not want a 4 or 5 KHz signal and the throughput that the government wanted, I think that a compromise bandwidth, something between that of PSK31 and perhaps 1 KHz with OFDM signal might be adequate for hams use on HF. As many have said before...if you REALLY want/need 100 error free copy, you are going to need an ARQ function and FEC. The trick is finding just how much of you signal you are going to give to FEC vs user data and how hard do you want to enforce ARQ. 73, Walt/K5YFW Walt DuBose wrote: Rud Merriam wrote: After a comment off list from Demeter I checked the Pactor specifications. It uses DBPSK or DQPSK. Why do the reports about Pactor indicate it is more robust than the QEX article would indicate? Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net Rud, If you go back to the DCC presentation of KN6KB of a few years back on his new software modem...he measured the robustness of Pactor, MT63 and several other modes and Pactor wasn't that much more robust than MT63 at a -5 dB SNR. If I invested a $K Buck or so in Pactor III and WinLink, I'd claim it was the best thing since sliced bread...woudln't you? 73, Wa;t/K5YFW Announce your digital presence via our Interactive Sked Page at http://www.obriensweb.com/drsked/drsked.php Yahoo! Groups Links
[digitalradio] Re: QEX Article on HF Digital Propagation
Rud, How did DominoEx rate? 73, Steve N6VL
[digitalradio] Fw: D-STAR using Analogue SSB
- Forwarded Message From: jk1zrw [EMAIL PROTECTED] Sent: Thursday, October 25, 2007 9:56:15 PM Subject: Re: UT118 Adaptor --- Tony Langdon [EMAIL PROTECTED] wrote: At 10:45 AM 10/26/2007, you wrote: Yes, it works any band. Only requirement is AF bandwidth of your rig. If SBB of HF has above requirement, we can use D-STAR in HF. (I ma nore sure now.) SSB radios typically don't have the bandwidth, as they cut off sharply around 300 Hz on the lower edge of the passband, due to the crystal filters used in 99.99% of radios. You would normally use FM mode in any case, resulting in the same 6.25 kHz wide signal as used on VHF (which would be legal on any amateur band in Australia, as it fits within the 8 kHz bandwidth limit). However, the performance is likely to be lousy, and any attempt to use D-STAR based systems on HF would require a more appropriate modem for HF conditions in my opinion. Yes, your are right now. SSB radios typically used crystal filter. But recent tequnical development are too fast, so we can make the ssb signal using Software (like SDR). For example, JH1DTX successed to modulate/demodulate from 50Hz to 3000Hz with PSN-SSB method (this is not SD mnethod). So, I think we can make the D-STAR rign in HF near future. The bandwidth(in AF) of D-STAR is 20Hz to 2400Hz. If future SBB rig has this bandwidth, we can. Satoshi 7m3tjz __ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com
Re: [digitalradio] QEX Article on HF Digital Propagation
One thing that would be helpful is that comparisons with Olivia would also indicate which mode they were using. Based on some of his other comments, he felt that you should not have to use more than 500 Hz on 80 meters, so this may have been 500/16. I always try and keep in mind, with mode comparison charts, is that it is for only one set of parameters with specified doppler/multipath, etc. If there was significant polar flutter, the PSK would not operate at all and Domino EX might be a good performer. 73, Rick, KV9U Rud Merriam wrote: There is a great article in the QEX I just received (Nov/Dec 2007). The author is Daniel Crausaz HB9TPL in Switzerland. He reports on modeling and testing PSK, RTTY, Olivia, MFSK, DominoEx and Feld-Hell under various propagation conditions. I need to digest his work with respect to the OFDM proposal since the results indicate PSK may not be an optimal choice. Olivia works better under all the conditions tested. MFSK seems to be second. At first glance I would say this is because the transmission rate is so slow for Olivia at 2.5 character per second. I would find that painfully slow for even a chat mode. Interestingly, RTTY performs about the same under all the conditions tested. PSK either works well or just fails. It has problems in flutter conditions which seem to me be the conditions prevalent a lot of the time. *Rud Merriam K5RUD* ARES AEC Montgomery County, TX /_http://TheHamNetwork.net_/ __._,_.__
