I am planning a local 6M test this weekend. Andy K3UK
On 8/7/07, Rick <[EMAIL PROTECTED]> wrote: > > > > > > > I see Steve's point, even though he did not just tell us the baud rate. > > I have been doing a lot of hunting around trying to find and understand > the single tone waveforms used in MIL-STD-110. They don't often mention > the actual baud rate because it appears that it is always 2400 baud. And > maybe that is all the time? > > One source that I found helpful, was a Norwegian doctoral dissertation > on Adaptive Turbo Equalization which made the background information a > bit more understandable since he worked through some of the examples. > > With 188-110B at the slowest 75 baud rate here is the calculation to > confirm the symbol (baud) rate: > > fa = Rc x Q x Rf x fs > > fa = data rate @ 75 bps > Rc = code rate @ 1/16 or .0625 > Q = bit rate per symbol @ 1 > Rf = frame pattern efficiency 1/2 or .5 > fs = symbol (baud) rate > > 75 bps = .0625 x 1 x .5 x fs > 75 = .03125 fs > 75 /.03125 = fs > fs = 2400 baud > > It seems hard to believe that this stuff can actually work, but until we > get the rules changed for text baud rate to at least 2400, we won't be > able to use this technology here in the U.S. on the HF bands as the > lowest band we can operate 2400 baud on is 6 meters which allows 19600 > baud. But it certainly can be tested on this band with hams that are > close enough to try it out. > Especially, noteworthy would be the AWGN on 6 meters with little QRM and > QRN so you should be able to get a good feel for how well it works down > into the noise since you could easily compare it to other modes. This is > made even easier these days since we have more rigs that can work on 6 > meters. > > Anyone doing that and who is willing to report on their comparisons? > > 73, > > Rick, KV9U >
