Perhaps the "strength" of the NBEMS modes needs to be put in perspective.
As the NBEMS web page clearly explains, NBEMS was designed for stable propatation paths up to 100 miles on HF, or 300 miles on HF using NVIS antennas *on both ends*. Just as Rick experienced, two days ago, I told a new digital user, an accomplished radio operator and DXer, W4NL, how to download and install the latest version of NBEMS and we sent the same file using PSK63, PSK125 and PSK250. It was 4 PM and first we tried 30m, but even MFSK16, without flarq, could not communicate very long, so I suggested we try 40m, a band on which we both have NVIS antennas. We were able to transfer a 616 byte text test file using PSK250, and took only one hit, which was caused by a loud static crash that I heard and saw the corruption of the text. The static crash was strong, but so were signals, which were S7-S9 on both ends (we were both running around 25 watts), so only once was the static strong enough to wipe out the data transmission momentarily. There was no QSB, because we were using the recommended NVIS antennas, and W4NL is exactly at the fringe area limit from me for NVIS coverage, which is generally considered to be 300 miles. The previous day, I transferred the same file using PSK250 on VHF, but over only a 25 mile distance, with no hits at all, which would be expected. We were both only running a couple of watts and both using a new design for a horizontally-polarized 2 meter antenna, called the "Jolly Roger" that is ideal for emcomm, as it is omnidirectional, 3 dB higher gain than the famous "Big Wheel", and costs less than $30 to make out of PVC pipe and #14 house wire. Anybody interested in the design can download a preliminary draft Word document describing the construction from http://home.comcast.net/~hteller/JollyRoger.zip . Four antennas have already been built locally from the instructions, and all four work the same, with low SWR at 144.2 MHz, and excellent gain. We all must remember that NBEMS is designed *specifically* for emergency communications when the repeaters are out of commission or unreachable, and over distances up to 100 miles on VHF or 300 miles on HF. All the tests over larger distances, from 500 miles to 2000 miles, or even greater, are much appreciated and also provide valuable user information, but it takes high performance modes of much greater bandwidth to sucessfully operate with ARQ in the presence of QRM, QRN, and changing propagation with time of day, as well as QSB most of the time. Trying to maintain stable communications over such long paths is not the objective of NBEMS, but only to achieve dependable point-to-point communications up to 100 miles on 2 meter VHF or up to 300 miles on HF, but using NVIS antennas *on both ends*. Before passing judgement on the modes included at present in NBEMS, it is suggested to test according to the expectations for NBEMS and then make a judgement. We are continually improving NBEMS, thanks to everyone's feedback and testing, both on HF and VHF, and in the near future, we will definitely incorporate a higher performance ARQ mode for Windows with higher throughput than MFSK16. Until that time, for Windows users, MFSK16 is the strongest mode for HF we support. Our thanks go out to everyone who is helping us to improve NBEMS. Please check the web page often, www.w1hkj.com/NBEMS, and be sure to use only the latest version for testing, as using a old version with a new one may be generate confusion, or even not work at all. We are incorporating changes daily based on the feedback we have received, and our own round the clock testing, as fast as reasonably possible, without stopping testing already being done successfully by releasing a too rapid succession of changes. We now display the latest version numbers at the very top of flarq and VBdigi, so you can easily confirm with whomever you are testing that you both have the same version. The April issue of QST headlines NBEMS on page 80 and does a good job of putting NBEMS in the proper perspective. 73, Skip KH6TY NBEMS Development Team ----- Original Message ----- From: "Rick" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Monday, March 24, 2008 7:36 PM Subject: Re: [NBEMSham] HF FLARQ Freqs? > The suggestion has been made to be up a couple kHz from the normal PSK31 > watering holes. Some of us use the ALE/FAE400 frequencies for NBEMS as > well, however I have been not been getting positive comments from those > who have been attempting to use NBEMS on HF:( They consider the protocol > too weak for practical use. I have had good luck on NVIS 80 meters > during daytime and have run up to PSK250. > > Here are some possible frequencies: 3584, 7074, 10136, 14094, 18104, > 21094, 28124. > > Since ALE/FAE modes use 1625 Hz as the center frequency, I have been > calling CQ on these frequencies with both ALE/FAE400 and NBEMS (mostly > with PSK63) with a 1500 Hz offset. > > Last night had an extended time with VE5MU on 3584. Later on another > station heard us when we switched to some of the Olivia modes using 2, > 4, and 8 tones. So you never know what you might find on these > frequencies. > > Is anyone using other frequencies as a kind of watering hole that does > not infringe on the main PSK31 space? > > 73, > > Rick, KV9U > > > rich3x wrote: >> Any set calling/test freqs established for 80 thru 10m? >> >> 144.144 on 2m? >> >> de Rich/N2JR FM18 >> >> >> ------------------------------------ >> >> Yahoo! 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