Charles, I think HF packet is a useful mode, but I can tell you that it does fall short in terms of sensitivity compared to many others.
More importantly, path simulations and on-air testing show that it doesn't take much in the way of HF channel distortion to cause throughput issues with 300 baud Packet. The mode tends to fail with moderate path distortion regardless of how high the signal-to-noise is so it's not something that can be overcome by turning on the amp. This doesn't mean it won't work as you an attest to, it just means that other modes are superior, especially if the goal is to get the message through with less power under adverse conditions. Tony -K2MO ----- Original Message ----- From: "Charles Brabham" <n5...@uspacket.org> To: <digitalradio@yahoogroups.com> Sent: Tuesday, June 09, 2009 9:23 AM Subject: Re: [digitalradio] Re: another "can you ID this mode" request > > HF Packet is also sensitive about the baud rate, 300 baud Packet won't decode > if you are set up for 1200 or 9600 baud. Note that no difficulty was > experienced in decoding from the recording at the proper aud rate, despite > some obvious signal fading. > > From my QSO at the southern tip of Texas, I QSO every day with a 300 baud > Packet station located 25 miles short of the Canadian border, and have done > so throughout the solar minimum. Using modern tuning technique, we encounter > very few resends. > > HF Packet will transfer data if the two stations are not aligned, but then > you get resends and a very slow data transfer rate. That typifies HF Packet > in the past, where tuning was a matter of luck as much as anything else. > These days we use a waterfal display to get on the same frequency, and the > difference is like night and day. - Am working on 'snap tuning' to make this > process automatic. > > Most of the disparaging talk about HF Packet is motivated by politics, and > does not come from actual knowledge. If you talk to the PC types who > disparage Packet, it turns out that very few of them have any recent > experience with the mode, they're still stuck in the 1980's. > > Charles Brabham, N5PVL > > n5...@uspacket.org > > > ----- Original Message ----- > From: Tony > To: digitalradio@yahoogroups.com > Sent: Tuesday, June 09, 2009 1:09 AM > Subject: Re: [digitalradio] Re: another "can you ID this mode" request > > > > > > > Thank you Tony > > My pleasure Frank. > > > couldn't get either MultiPSK or MixW to decode it > > Understand - not the most sensitive mode -- needs a fair SNR to decode well. > > Tony -K2MO > > ----- Original Message ----- > From: "frankk2ncc" <frank.k2...@gmail.com> > To: <digitalradio@yahoogroups.com> > Sent: Tuesday, June 09, 2009 1:41 AM > Subject: [digitalradio] Re: another "can you ID this mode" request > > > Thank you Tony. Seemed like that's what it was, but couldn't get either > > MultiPSK or MixW to decode it. I've worked 1200 and 9600 baud on VHF/UHF, > > but never 300 baud HF. I'll try again and a little harder this time. > > > > TY! > > > > f > > > > > > > > >
