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[aprssig] RE: 6 meter APRS or meteorscater?

Bill Vodall WA7NWP wa7nwp at gmail.com
Wed Jan 23 22:31:40 UTC 2008


What data mode was used in the examples below?  I see one mention of
"PSK" and never any mention of 1200 baud AFSK  AX25.   I'm still
skeptical of how a 500 millisecond packet is going to work in a system
with 300 millisecond openings.

How about having a super short MIC-E packet with no path for a "PING"
packet to look for minimal openings?   I can be generating those on a
regular basis by the end of the month.

To confirm, you are now thinking of 50.62 yes?   We'll have at least a
half stations on there in the PNW by spring.

73
Bill - WA7NWP

> Here is our project:
> http://www.ew.usna.edu/~bruninga/meteors.html
>
> Oh, also found that the daily reliability is worst at 8PM and
> best at 8 AM by a factor of 3 or so.  And annual reliability is
> worst in February and best in the summer by a factor of 4 or so.
> But the message still gets through.
>
> Here are some data points I got out of some old reports.  Notice
> the 4th example when 4 receivers were added!
>
> * 600 mi, 2 kbd, 200W, 1 RX, 10+10dB antennas, worst case wait
> time was between 1.3 to 3.3 minutes for a 150 byte message at 38
> MHz.
>
> * 500 mi, 2 kbd, 400W, 1 RX, 10+10dB antennas, worst case wait
> time was between 1 to 4 minutes for a 50 byte message at 38 MHz.
>
> * 1000 mi, 2 kbd, 400W, 1 RX, 10+10dB antennas, worst case wait
> time was between 2 to 8 minutes for a 50 byte message at 38 MHz.
>
> * 600 mi, 2 kbd, 2Kw, 4 RX, 2+10dB antennas, wait times 3 to 10
> seconds for 130 bytes at 38 MHz
>
> * 400-900 mi, 2kw, 8+14 dBi, 15 to 48 secs for 130 bytes at 38
> MHz
>
> * 600-1200, 750W, 2Kbd, Dipole +13 dBi, 2 to 5 minutes for June
> 46 MHz, PSK, -126 dBm for 15 bytes.




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