Leigh, I have not been following this SSTV discussion very closely as I got the impression that it was analog SSTV when MMSSTV was mentioned as a program. Or is this actually digital SSTV? Can you give us a capsule account?
Do you have any knowledge of any tests that have been done between RFSM2400 and the WinDRM/EasyPal type of OFDM? Even though this has to be done in the voice/image portions of the bands here in the U.S., it just does not add up that no one has done this kind of testing yet. And I have asked about this repeatedly. Are you or anyone else interested in doing these kinds of tests? I just recently got the capability to key up some of these modes (and most any sound card mode) from 160 to 6 meters, but on some bands with minimal antenna capability. Mostly ground mounted Butternut vertical. One of the very helpful things about the voice bands is that you can make contact on voice and then transmit the digital image on the same frequency. Very convenient if a problem comes up. The only down side is that you need reasonable good signals. But then again, I think we are going to find that for the most part, we will need fairly good signals for these fast modes. WinDRM and EasyPal require something around +8 dB S/N although the STANAG modems are supposed to be able to go much below that point. We may be able to partially simulate that by reducing power. Speaking of power, I can run well over 100 watts on most of the digital modes as I do have an Ameritron ALS-600 amplifier. For those who are thinking that this is an SSTV experiment, it really is more of a surrogate for the modem type. The only reason for using image data instead of text data is to meet the requirements here in the U.S. 73, Rick, KV9U Leigh L Klotz, Jr. wrote: > In the US, we can send images in 500Hz bandwidth in the cw/data segments > of the band, but if the bandwidth is higher than 500Hz, we must move to > the phone bands. Andy is trying to foster a set of image operations > down in what works out to be in the US data segment, so if we want to > play, we have to do it in 500Hz. > There was a discusion of OFDM recently here and I thought the upshot was > that the throughput for 500Hz coding using multiple QAM carriers in 500 > Hz would result in transfer times too long, so I suggested maybe we try > making the MFSK analog mode more readily available. > The DRM stuff is quite exciting and I hope to try it out sometime, but > for now at least, it will have to be in the image/phone band, where we > then can't do kbd-to-kbd data. > >
