[aprssig] PSAT & igating and Optimum antenna
Lynn W. Deffenbaugh (Mr)
ldeffenb at homeside.to
Sun Jun 7 22:57:19 EDT 2015
This is why APRSISCE/32 supports a "NoGate ME" option on it's RF ports.
If one of it's own beacons is heard back, it is NOT sent to the APRS-IS
if this option is in force so that the only packets that should show up
on the APRS-IS are those heard by other IGates.
If anyone sends a messages to an IGate running in this mode, it may be
gated to RF by other IGates, but for satellite gates, this really isn't
much of an issue.
Lynn (D) - KJ4ERJ - Author of APRSISCE for Windows Mobile and Win32
On 6/7/2015 4:46 PM, Lee Bengston via aprssig wrote:
> It's actually part of an algorithm running on the IS servers that
> helps facilitate transmit Igating. In the event that your IGate is
> beaconing only on RF, the way that other IGates in your area "know"
> that your station is connected to the Internet is via those beacons
> that look like they are sent directly to the IS. Without those "fake"
> beacons, a nearby IGate would gate a message addressed to your station
> from IS to RF when it really didn't need to. So in a nutshell, it's
> part of a "little scheme" to prevent gating packets from IS to RF when
> it's not necessary.
> I think in the case of your test below, the IS server didn't know the
> difference between a packet generated by your mobile vs. one generated
> by your IGate due to using the same SSID.
> I'm just the messenger on this one. :-)
> Lee - K5DAT
> On Sun, Jun 7, 2015 at 2:18 PM, Max Harper via aprssig
> <aprssig at tapr.org <mailto:aprssig at tapr.org>> wrote:
> Then why does the timestamp on findu match the time the beacon was
> received back and not the time it was actually sent. I have
> noticed this behavior many times over the years using various
> Igate software programs. I can also duplicate the problem anytime.
> Back years ago when I first discovered the problem I did a test. I
> configured my mobile station to the same ssid as my igate and
> drove to a digi that was about 25 miles away. Using only a few
> miliwatts of power I sent some beacons that my igate couldn't hear
> direct, only the digi. The beacons appeared as if my igate had
> sent them directly to the aprs-is with no sign of the digi.
> I don't know if it is an igate problem or an aprs-is problem but
> I see it happen all the time. I can understand it being considered
> a duplicate, but why does the path get changed and made to look
> like it was sent direct to the aprs-is when it wasn't? And the
> example beacon WAS sent out RF only.
> Max KG4PID
> aprssig mailing list
> aprssig at tapr.org
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