Scott, I guess you are talking abt C13 and C17 ? When you replace them, do you see improved decoding?
sorry for the hassel. vy 73 de Mike oe3mzc ----- Original Message ----- From: Scott Miller To: [email protected] Sent: Sunday, September 13, 2009 4:42 AM Subject: Re: [tracker2] Tracker2/Display & poor decoding Hi Mike, I'm kind of fed up with the 2211 myself. I've been doing a lot more testing on the OT2ms before they ship these days, and a significant portion of them need to have the 0.027 uF capacitors replaced before they ship. I'm not sure the batch sent to the contract manufacturer is really meeting specs. I haven't run into any that didn't get up to par with the capacitor replacement and a thorough cleaning of flux residue. Still, it's a lot of hassle. I've got a few boards on the way to test a new MX614-based layout. When those come in (sometime late in the week) I'll start doing some side by side comparisons. Assuming I can get my crashed workbench PC up and running again. I already bought a replacement, but I can't run the software I need under Vista, and I can't get the machine to load XP Pro. Scott Mike Zwingl oe3mzc wrote: > > > Hi, > we have exactly the same problem and we are no newbies to packet radio > modems. > The XR2211 decoder should perform much better, than it sometimes does in > OT2m. > This modem chip is also used in some other tncs... > but I did not change it for an TCM3105 or similar in the OT2m -so far no > time to test this... > However we observe many OT2m units, that show POOR DECODE on 1200baud on > different radios and locations. > Some only decode less than one third of all heard packets..we do not > know why... > However, we have also seen some OT2m units that do significantly better > than that, running same firmware. > We are also aware of the wrong capacitor in the audio filter circuit of > some OT2m serial No. batches, but even if we soldered the correct C > it is still showing very odd effects with poor decode and digipeater > performance. > We would be glad to have some solution offered, since OT2m is starting > to get widely used in our national APRS network as an intelligent > digipeater > or replacing old tncs, that could not do the NEWn-n paradigm. > > hw? > vy 73 de Mike > oe3mzc > > > > ----- Original Message ----- > *From:* Mark Cheavens <mailto:[email protected]> > *To:* [email protected] <mailto:[email protected]> > *Sent:* Thursday, September 10, 2009 3:31 PM > *Subject:* Re: [tracker2] Tracker2/Display & decoding > > > > With the modem chip used it is rare that a "weak" or "noisy" signal > will get decoded. Is the audio "packet" 9600, 1200, or speaker audio? > > With 1200 baud packet you need to have de-emphasized (sp?) audio to > the modem (TNC). Speaker audio DOES have de-emphasis, as should a > "1200" baud port of the radio. > > (FYI- 9600 had NO pre- or de- emphasis) > > Just because you can HEAR a packet, does not mean the TNC can decode > it. The signal to noise radio need to have a LOT of signal, and VERY > little noise. > > Mark > KC5EVE > > > At 01:02 AM 9/10/2009, you wrote: > >> >> >> Hi there, >> >> I've Tracker2 connected to a Nuvi350 and was wondering why >> sometime it >> took a while before I could see some of the callsigns get into the >> Favorite (after I did a delete all). So, I added an LCD display to my >> Tracker2 yesterday and found out that most of the time, Tracker2 >> couldn't decode the packets (i.e. not displayed on the LCD) >> especially >> the weak ones. Now I'm wondering what else I need to do .. Anyway, my >> setup is .. Kenwood TMV71A/Data/BandB <-> Tracker2 with LCD <-> Nuvi. >> I brewed my own cable between the TMV71A and the Tracker2.. sending >> packet out does not seem to be a problem. Is there anything in the >> configuration that I need to do? >> >> TIA, >> Mohd/9W2TPT > >
