[aprssig] PropNET Lessons Learned [was: 6m MS network PerformanceMonitoring!]

Robert Bruninga bruninga at usna.edu
Fri Jan 4 08:22:35 EST 2008


This is great info and well prepared.  Do you have any
quantitative data?
How many packets per hour success?

I remember the first MS we did with the routines in APRSdos and
on 6m in 1995.  I remember reliable 6m success from MD to Iowa.
But after many PC changes, I cannot find any quantitative
record.  I just remember that 6m was an order of magnitude
better than 2m.  But my meteor web page does show more than a
dozen success on 2m in 1999, but we did not do 6m that year.

I think the major difference is that MS requires gain antennas
(Beams).  The signals are there, but are weak when they break
through.  Without 10 dB of antenna gain, there is a drastic
affect on decodability.  But people are not going to have lots
of beams for 6m.  BUT, all it takes to get 12 dBi of
unidirectional gain is about 120 feet of wire strung as a long
wire in the initended direction.

Using this gain, and my recollections from 1995, where I used a
3 element beam, I anticipate success.  Of course we need to get
some radios on the air to know for sure.

Can you opinion on our best freq?  We do not want to aleniate
the PROPNET folks by usurping their 6m freq, unless of course,
they want us there.


> -----Original Message-----
> From: aprssig-bounces at lists.tapr.org 
> [mailto:aprssig-bounces at lists.tapr.org] On Behalf Of Ev Tupis
> Sent: Friday, January 04, 2008 6:47 AM
> To: aprssig at lists.tapr.org
> Subject: [aprssig] PropNET Lessons Learned [was: 6m MS 
> network PerformanceMonitoring!]
> I would like to offer insights.  None of them should be 
> construed as poo-poohing the possibility of using 6m FM AX.25 
> for emergency e-mail support systems.  Instead, they are 
> shared as lessons learned, upon which you can build for 
> greater success in your efforts.
> Based on PropNET-based Meteor-scatter experiments in the
> --- Equipment Parameters (EP) ---
> 1. FM Tramsceivers (converted and tweaked Motorolla rigs)
> 1a Open squelch (see 5a below)
> 2. 100-watt RF output
> 3. 100-ft of Belden 9913 cable
> 4. Ringo Ranger vertical
> 5. KPC-3 TNC w/ROM 8.2, configured with...
> 5a Ignore carrier detect
> --- Operational Parameters (OP) ---
> 1. Followed the 4-quadrant TX/RX model
> 2. Followed the 15 seconds of continuous TX/ 45 seconds of RX
> 3. 53.530 MHz used for several trials, 50.620 MHz used for
> --- Reasons ---
> EP1 - FM mitigates Doppler shift.
> EP1a- to decode weaker signals
> EP2 - More ERP = greater opportunity for success
> EP4 - The "radient" of a meteor burn is random.  The 
> "radient" of a meteor shower is constant only from a 
> cosmological perspective.  From an earth-based observer's 
> perspective, it appears to move as the earth spins.  The 
> Leonids shower appears to come from the constellation Leo.  
> That constellation moves in the sky relative to any one 
> observer on earth, as the earth spins on its axis.  An 
> omnidirectional vertical assures that RF is always bathing 
> the entire sky in all directions.
> EP5a-For MS experiments, you don't want local participants 
> "holding off" your TX.  There is assumed QRM from all 
> participants in the same quadrant
> OP1 & OP2 - these were Bob's recommended strategies for the 
> reasons posted on his web page
> --- Major Lessons learned ---
> With these parameters, it is obvious when meteor events occur 
> and when they end.
> 1. Receptions ceased when meteor events ceased.
> 2. Even during meteor showers, the number of reported 
> receptions were statistically small when compared against the 
> number of transmissions occurring.
> 3. Clocks migrated.  People in quadrant 1 were often found 
> TXing during times when they should have been RXing.
> --- Conclusion (as I wax poetic) ---
> The human spirit can find ways to be successful in whatever 
> it chooses to focus its' effort upon.  Use the above 
> information only to avoid the pitfalls of those that went 
> before you as you attemp;t to find a path to the destination 
> that you're pursuing.
> I can offer additional information that may help, but will 
> let this settle for now.
> Best wishes, truly!
> Ev Tupis, W2EV
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