Kevin (callsign?) wrote... > 1) 15 seconds only matters, if someone can hear my packets. That is > still an issue, as they are not getting through for some reason. Maybe > 5 to 10 get through and are displayed on APRS.FI for the 20 minute > trip to work in the morning. Nothing else gets through. The packet > frequency is not that busy. I can hear packets from several other > stations, and they all display on my Nuvi 350.
It depends what you mean by "matters". If there are no other APRS users around you, and no digis, a 15 second beacon rate won't affect anyone. If you are in a busy area, a 15 second beacon rate is abusive, whether your tones are being decoded or not. You say the frequency is not that busy. Are you listening at your location to determine that, or at the location of the digis all around you? If they are much higher, the frequency may appear to be a lot busier than it appears to be to you. You need to do some troubleshooting to determine if you have a problem or not. So far the only symptom appears to be that when you look at somewhere like aprs.fi, you think your "success" rate should be higher. We have no idea where you are, what the APRS infrastructure is around you, how many IGates there are, and so on or the real reason that your success rate is so low. > 2) Have tried setting SMART to ON with appropriate parameters (as > suggested here), and an INTERVAL of 2 minutes. With these settings, I > get two or three packets through on my 20 minute trip. That seems like a pretty low success rate. The question is why? > 3) Do I have something wrong? Does a packet contain all the last > several coordinate breadcrumb trails in it (several gps coordinate > sets that are stored over the last several minutes)? Or does a packet > only contain the last single coordinate set, for the moment? I think > the latter. So far, we have no idea if you are doing anything "wrong". A position report only contains the current position, usually as output by your GPS receiver. The T2 doesn't store any past position reports that you sent. They are sent on their way and that's it. They are either heard or they are not. > 4) I can hear the packets fine with my stand alone HT radio, with > APRS. They should like everyone else's packets. But maybe I do > need to adjust the volume settings (what is that command?) so that > the modulation is improved. Maybe I am undermodulating the packet, > with my audio from the TRACKER? Checking the deviation should be the very first thing done when a tracker or TNC or whatever is first put on the air. Not everyone has a service monitor, worth perhaps $10-30,000. A few people (myself included) have a deviation meter worth a couple of hundred or whatever it was. Some have made their own for virtually no cost. Setting deviation by ear should at least get you in the ballpark. If you crank the level all of the way up (hopefully not on 144.390 if the frequency is busy around you) and then keep turning it down until it sounds quieter on a nearby receiver. Then turn it down some more. It certainly doesn't hurt to compare your deviation to other signals that you hear, but keep in mind that many of them could be over-deviated. The other thing to check is the transmit delay. Too short and no-one will be able to decode your tones. Too long and it's a waste of bandwidth, which is a valuable thing on a shared network. I usually go with 100-125 ms and have good success. I would consider anything over 250 ms as being too long, but you need to determine what "works" for you. It would be a shame if you used 500 ms thinking it improved your success rate if all it did was cause your beacons to be half a second longer than they needed to be. If I was asked to guess about your deviation, I would guess that it's over-deviated rather than under-deviated. Of course, that's just a guess. The odds would be in my favour though. > 5) Also need to check my radio and its baud rate. Do not recall if it > is set to 1200 or not. It should be at that setting I assume? If you were sending tones at 300 "baud" no-one on 144.390 would be able to decode your tones. Or are you referring to a "1200 / 9600" setting in the radio? Most radios that have this setting use pre-emphasis for the 1200 setting. That is what you should be using. > Thanks for all the comments. They all make sense during investigation > of optimal APRS. Optimal APRS means a high success rate for you while not undermining the success rate of stations around you. You need to do some troubleshooting. Don't forget... the T2 could be "perfect" but if your radio is putting out 50 mW because of a blown final, or if your SWR was sky high because of an open or shorted coax feed, or if the antenna itself was sub-par, your success rate could be abysmal. You could give your callsign so others on the list could do more than speculate. With a callsign, we could at least see where you were, look at the APRS infrastructure around you, and see what was in the beacons that did make it to an IGate. While deviation and transmit delay are extremely important, using a bogus path would cause the digis around you to completely ignore you. Like I said... you need to do some troubleshooting. 73 es cul - Keith VE7GDH -- "I may be lost, but I know exactly where I am!"
