Thanks, Rick. I have suggested in the past that your SCAMP/WINMOR "channel busy detector" could be inexpensively back-fit into WinLink PMBOs. Has anyone taken a look at this?
73, Dave, AA6YQ -----Original Message----- From: digitalradio@yahoogroups.com [mailto:digitalra...@yahoogroups.com]on Behalf Of Rick Muething Sent: Saturday, April 10, 2010 8:30 AM To: digitalradio@yahoogroups.com Subject: [digitalradio] Re: Unattended narrow mode transmission "protection" All, I have been busy with WINMOR but do monitor the group and thought it might add some balance to put forth some facts and observations. 1) The majority of WL2K users are not 30 day wonder hams on expensive yachts. Marine mobile users are probably < 20% of all registered WL2K users (about 15,000 total current active users). 2) Those that are Marine Mobile have (on average) the same radio skills as the average ham.some much better. Getting digital radio to work at all on a small sailboat (most MM users are not wealthy and have "yachts" of < 35 feet) when you are sitting in a plastic boat inside the antenna near field is a challenge. I have seen and helped set up over 100 such installations. 3) Certainly there are a number of operators that fail to "listen first" or don't use the tools and procedures recommended to connect. E.g. AirMail limits the calling cycle to normally < 20 seconds for most stations. Unfortunately bad operators and procedures exist in ham radio in every mode. 4) Marinas by and large don't do or sell radio installations (I have NEVER seen even one). They sell GAS/Diesel, dockage, supplies, beer and bait. In fact most marine radio service companies have minimal experience with ham radios or HF digital modes. 5) Scanning has been used in the past to improve the utilization of HF Pactor server stations but can be an issue. Pactor has some but limited busy channel detection capability. WL2K is now looking at and testing alternatives to the conventional scanning used in Pactor. The new WINMOR protocol allows more options and experimentation. a. RMS WINMOR server stations [Beta operation started in January 2010] operate on ONE frequency which can be changed (on the hour) during the day (most use 1 - 3 frequencies over a 24 hour day). The frequency list clients use indicate which frequency is in use on which UTC hour. The client software (RMS Express) shows users ONLY those frequencies in current use along with the propagation prediction to the remote server stations. Users can refresh their server station list over the air or over the internet if available. b. WINMOR uses an effective "channel busy detector" to warn users if a channel appears busy in the bandwidth of interest. The detector isn't perfect (neither is the human ear!) but it can detect most modes even in weak conditions (SSB, CW, PSK, Pactor, Olivia, WINMOR etc). c. The RMS WINMOR stations (servers) also have a similar DSP based detector which can block a reply to a connect request. This will prevent for example answering a connect request "over" an existing session/QSO not audible to the station originating the connect request (hidden transmitter situation). We're still experimenting and refining this but it definitely helps avoid accidental interference. To summarize: Painting all Winlink users with a broad brush of "wealthy yachties with limited radio skills" is no where near the truth and is an obvious attempt distort the facts to promote some agenda. If given the flexibility to work on and experiment with these digital modes it is possible to address issues and make progress improving our hobby. If we try and legislate every detail we end up generating rules or band plans that become obsolete quickly. This discourages experimentation (I still hope that is part of our hobby.) and progress. I don't have the time to get into flame wars or extended blogging ..If you have a legitimate technical question on WINMOR or a question about WL2K I will try and answer it with accurate facts. 73, Rick Muething, KN6KB