Hello Rick, Try MT63 under heavy QRN conditions; alot of downsides but for bucking qrn/qrm have found this about the best....CHIP modes also seem to do well in high qrn environments....both are wide bandwidth (relatively) so this may well be a part of it all..
73, Bill N9DSJ --- In digitalradio@yahoogroups.com, kv9u <[EMAIL PROTECTED]> wrote: > > Well, tonight my experimenter friend and I got taken out by QRN when it > came to digital modes. We often run a Tuesday night sked. We started on > MFSK16 and then tried to go to the ALE 141A mode and no luck with that > or FAE. It just could not handle that much QRN. > > We then went back to MFSK and decided to try DEX11/FEC which I was > hoping would work as well as it has been during quieter times. No luck. > Hardly any print so dropped down to 8 baud and still no good. What a > disappointment. > > Back to MFSK, but even that was getting more and more spotty with lots > of hits and even long stretches of no print at all. The QRN levels were > at or exceeding 50 microvolts (S9 on my calibrated S-meter). The > signals seemed to have deteriorated as well and actually appeared to get > much weaker. I don't think it was just the S/N ratio causing this but > was a combination of weaker signals and stronger QRN. > > In fact, I got so desperate for any kind of mode that I switched to CW > and eventually I moved up a bit and he realized that I was sending CW in > his passband. Even then, the communications were extremely difficult > with the CW tones being chopped up badly by the QRN which were at the > serious popcorn level. Increasing filters did not really help much. It > did increase the S/N ratio but the noise bursts tend to block the > signal, making it more difficult to copy than with a wider filter. > > Of all the sound card modes we have now, I would like to hear some > opinions of what you think is the best one for these kinds of conditions. > > 73, > > Rick, KV9U >
