Hey Nate: "Most outstanding was Nate Duehr's (WY0X) successful extraction of "Packet" data from deep in the modulation. He, using computer filtration and blanking techniques, removed the DTMF zeros and brought the packet data up by what must have been at least 30 db.. He then put this on his server for any and all to try to decode."
Nice work here. Many thanks to you. If I ever have a problem with my system, I'm come running to you. Don, KD9PT ----- Original Message ----- From: Scott Overstreet To: Repeater-Builder@yahoogroups.com Cc: [EMAIL PROTECTED] ; [EMAIL PROTECTED] ; [EMAIL PROTECTED] ; [EMAIL PROTECTED] ; [EMAIL PROTECTED] ; [EMAIL PROTECTED] ; [EMAIL PROTECTED] ; [EMAIL PROTECTED] ; [EMAIL PROTECTED] ; [EMAIL PROTECTED] ; Scott Overstreet Sent: Friday, December 15, 2006 7:19 PM Subject: [Repeater-Builder] Mystery Signal Hello All By this time all of you who have been following and or helping with the identification and location of our mystery signal have probably figured that something has happened due to the silence from this end. Well, if so, you figured right----the signal quit last Wednesday evening and hasn't been heard since. To add some details-----we made ---seems like about the fourth---- contact with a related arm of our emergency com. organization that has a station using the large municipal tower that I have mentioned previously as being in the approximate center of our Doppler DF convergence. This time, in spite of their repeated assurance that all was well within, they agreed to shut down their station in total. I also ask that they make contact with other hams in their area of their town and particularly those running packet gear of any sort in the hope of finding the signal source. In amazing coincidence to when the tower station was shut down, the mystery signal quit. Nobody is admitting responsibility yet---and the signal has not returned -----yet ---in spite of my being told that the tower station is all up again. Looking back at all that happened in identifying the signal is amazing. It started with one of our hams (N6NFI) making a waterfall audio frequency spectral analysis of the signal's modulation which identified the presence of a 100hz. PL tone and the three tone bursts as being DTMF zero's-----this explained why our repeater was opening and announcing errors. Next, N6NFI made a wave file recording and sent it on to all of us locals and one of our guys (KR6DD) who was in Maryland on vacation. He analyzed for a while using a borrowed computer finally announcing that he thought that he could see some buried data---he then ask for another recording with open squelch to be sent to him. This was done by N6NFI and I, at this point, put my first message on Repeater Builder (I'm a member of this group) offering the wave file for identification at AE6EO's server. You are all up on the flurry of RB messages that followed this. Most outstanding was Nate Duehr's (WY0X) successful extraction of "Packet" data from deep in the modulation. He, using computer filtration and blanking techniques, removed the DTMF zeros and brought the packet data up by what must have been at least 30 db.. He then put this on his server for any and all to try to decode. AE6EO back here went to work on it and determined that the format was definitely ham packet format but wasn't able to decode much more than that the origination station was coded as a ? mark-----the rest of the data was interrupted by the DTMF tones. About this time, Bill, K6TYO, near here, precisely measured the frequency of the mystery signal as being almost dead on channel and stable which together with several comments from RB people about some Kenwood and Yaesu radios for the ham market being capable of producing the DTMF preamble made it pretty clear that we were looking for a radio of this sort with the DTMF preamble inappropriately activated that had been some how shifted in memory channel to what was in a previous application used to talk to our repeater---what a mouthful! ---and--- that was now connected to a packet controller that was set up to announce the station's presence every half hour. Now, this and back to the top you have the whole picture to this point. And, finally, I want to thank all who participated ,no mater how----you all helped and I and we all appreciate your efforts and suggestions. I would like to list all of you but there are to many to do that. Thanks again! Scott, N6NXI SPECS----Southern Peninsula Emergency Repeater System---- Mountain View, Calif. 145.270,---224.140,----440.800 !DSPAM:1016,458349db934385209328925!
