>I agree. Static crashes are a powerful QRN source here too. >Guess Olivia would be better, even 8/250 would stand a better chance of >good copy.
>In spite of strong signals, if there is no "second chance", it does not >matter much how clever Varicode is. It is certainly a big step ahead on >quiet bands, but when QRM dominates, it is simply not enough. >73, >Jose, CO2JA Hi Jose, We are using PSK63 to PSK250 on 2 meters for NBEMS with excellent success and fast data transfers, as there is essentially no problem with static crashes on 2 meters. Wether we use PSK63, PSK125, or PSK250 is simply a function of the path loss on 2 meters we have to overcome to get a usable S/N, and there is no QSB to contend with either (up to about 100 miles). However, as you note, static crashes are a big problem for PSK31, and a huge problem for PSK250, so those testing NBEMS on HF have had to resort to MFSK16 (already included in the NBEMS software), which is much less disturbed by static crashes. However, data transfer is very slow using MFSK16, especially after adding ARQ, so we are seriously considering using DominoEx, which is faster, easier to tune, within 1.5 dB of the weak signal performance of MFSK16, and that we hope is more like MFSK16 in tolerance to static crashes, but we do not have enough experience to know if it is or not. The problem is that DominoEx is not used a lot, so if you, and others reading this post, can compare DominoEx11, or DominoEx16, to MFSK16 during times of many static crashes and let us know the result, I would greatly appreciate it. Multipsk supports both DominoEx, and MFSK16 under Windows, as does fldigi, under Linux. 73, Skip KH6TY NBEMS Development Team
