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<DIV>From: "Wes Johnston, AI4PX" <<A href="mailto:wes@ai4px.com" ymailto="mailto:wes@ai4px.com">wes@ai4px.com</A>><BR>Subject: Re: [aprssig] 9600 APRS net experiment in Central NJ<BR></DIV>
<DIV>summarize:</DIV>
<DIV>1200 185ms loud packet burst </DIV>
<DIV>9600 158ms small short burst of white noise. </DIV>
<DIV>===================================</DIV>
<DIV> </DIV>
<DIV>This is a savings of 27ms. based on his numbers. I have seen numbers shorter and longer than 150ms for keyup. This doesn't sound like alot of savings but every little bit helps.</DIV>
<DIV> </DIV>
<DIV>9600 on VHF ? I have never really seen this work on even on packet</DIV>
<P>I have seen 2400 & 4800 on VHF but a true 9600 no because of bandwidth restrictions. </P>
<P> </P>
<DIV>9600 on UHF yes it does work. </DIV>
<DIV> </DIV>
<DIV>injection points and output points</DIV>
<DIV>9600 input requires more drive than 1200 and is injected past the audio amp befor the exciter because of bandwith limits by filtering. </DIV>
<DIV>9600 output is at the dicriminator before the filtering of the amplifier of the speaker. </DIV>
<DIV> </DIV>
<DIV>1200 input is at the microphone</DIV>
<DIV>1200 output is at the speaker. </DIV>
<DIV> </DIV>
<DIV>For the amount of data that is pushed we should drop back to 300bps, 150bps or slower. That is all that is used.</DIV>
<DIV>If you have a D700 you know of the blanking that takes place when the APRS transmits. and if you are in a conversation on the other side of the radio it gets that blanked out space while APRS is transmitting. </DIV>
<DIV>Move that up to 440 and run APRS at 9600. no blanked out conversation on EITHER VHF </DIV>
<P>or UHF. Is that an improvement ? Yes. </P>
<P> </P>
<P>I don't know how the D710 or the other radios deal with this but the ideal here is to improve on systems and move forward out of the dark ages. I only see patches here and not fixes. There is only so much that we can get out of one frequency. If you want to beat a dying horse then stay at 1200 and use multiple frequencies. One for travellers 144.390 giving local repeater info and digi's. 145.390 for local service and they are both tied to Igates and both pulling data that they feel is needed but not everything. </P>
<P> </P>
<DIV>The points are different to get the needed speed. The manufacturers are putting them into the newer radios and you can adapt them to older rigs. </DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV>I have been experimenting in Virginia for years with 110, 300, 1200, 9600 and up to 128k. The higher speeds are the direction we should have gone in years ago. I have 9600 APRS up in my area of virginia. unfortunately no one else in the are has used it but myself. I will be expanding it this spring and see if there is more interest. </DIV>
<DIV> </DIV>
<DIV>Should they mix information directly between bands ? Some of it yes the resto of it no. Keep them separate and let the data flow in and out of the IGATE. let the individual system put the data from the APRS IS servers. </DIV>
<DIV> </DIV>
<DIV>*** PLEASE SUMMARRIZE THE MESSAGES WHEN YOU RESPOND ****</DIV>
<DIV>These messages are long enough without 20 messages behind them for a simple answer. </DIV>
<DIV> </DIV>
<DIV>Mike K4MQF</DIV></div><br>
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