[NLRS] Super tropo

[Dave, WV9E]

 I have noticed sometimes when a huge red blob appears on the map it was 
caused by some station porting the internet traffic to the RF side. A
false red in that case.   Also, your home APRS station can function as a 
propagation detector as DX will be heard direct. The old WinAPRS software 
could list stations by "Digi" and the directs were easy to see.
 Just my pennies worth.  Considering what K0CQ mentions also, it's not the 
best way but atleast can give you a clue and perhaps some early warning.

Dave, WV9E

>
>
> You asked about the performance of APRS as a propagation indicator. APRS
> AFSK packet has two thresholds. First is that of FM some 30 dB stronger
> signal required than for SSB and then the typical PLL AFSK detector
> requires a virtually noise free signal, far better than just copyable
> voice so when APRS links see long they are STRONG. To FM AFSK, its DX
> when its "local" on SSB at the same distance.
>
> I used to be remote sysop for a number of Iowa packet nodes. Their
> default software settings would make a node accept a distant node as a
> direct link if it heard a beacon from it once, such as by aircraft
> reflection and then it would try only the direct connect to an
> unworkable node most of the day. During that time it would not connect
> to the nearest node and would put out beacons that it was "working" the
> distant node. It had to have settings to control what nodes it accepted
> as workable and that those sporadic nodes were not considered workable.
> A preferred list and then even under conditions of strong DX it would
> continue to connect and pass traffic automatically. So the properly set
> packet nodes wouldn't show DX propagation because it destroys the
> network functioning. The qrm possible doesn't help the preferred links
> though. The nodes broadcast shows only what it hears, not what it
> actually has passed traffic with, unless the distant modes are rejected.
>
> APRS is beacon based, connections are almost not used. Every APRS
> station blatts a periodic beacon, with a generalized digipeater list and
> nearly all APRS stations act as digipeaters, plus there are dedicated
> digipeaters in the network. Some stations monitor and transfer to the
> internet for distant digipeats. Most of the digipeaters are running
> stock TNC firmware, not node firmware and so have no discrimination
> against distant signals.
>
> 73, Jerry, K0CQ
>
> On 7/31/2012 9:58 AM, Doug Reed wrote:
>>
>>
>> Interesting. On the Mountainlake 2M APRS web page at 9:45AM, there is
>> one small spur of reception from Mpls to Proctor and a bunch of
>> indication from Missouri and even more in Texas into Mexico. When I zoom
>> in a bit on the map it shows a lot more widespread reception in our area
>> reaching around the 5-state area, through Iowa into MO and KS, Wisconsin
>> into MI and IL.
>>
>> So I would think that 2M should be good as well. Nothing showing on DX
>> Sherlock on any band above 10M.
>>
>> 73, Doug Reed, N0NAS.
>>
>> Bill Davis wrote:
>>> W0GHZ  50db above noise on 10Ghz this am -- even worked him portable 
>>> from the dock SSB
>>> K0AWU
>>
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