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-   -   APRS - 10w enough? (http://www.risingsun4x4club.org/forum2/showthread.php?t=16180)

CardinalFJ60 07-27-2011 01:33 PM

APRS - 10w enough?
 
I feel like 10w is plenty...just wanted double check.

APRS is really cool, and since my wife isn't really into the overland adventures I would love to give her some peace of mind when we're out and about (or as they say up north oooot and aboooot)

I've been investigating piecing together an APRS setup with a used 2m radio, the TNC, small GPS, the setup is coming in at about $150-200 as I look at the parts. I love the idea of wiring it up so it's on all the time. (could also act like lo-jack)

But then reality sets in with my knowledge and available time to put one together...now...I'm thinking about just buying one that's pre-fab...like the one from Byonics.com. the "micro-trak RTG"....it's a 10w transmitter.

http://www.byonics.com/mt-rtg

any thoughts??

wesintl 07-27-2011 02:20 PM

Depends on how far away from the tower you are.. QRO bro

DaveInDenver 07-27-2011 02:58 PM

Quote:

Originally Posted by wesintl (Post 188037)
Depends on how far away from the tower you are.. QRO bro

You really do want to use just enough power to hold the path because digital modes are more efficient.

If you're trying to reliably get into aprs.fi in the backcountry, more power is probably good but APRS digipeaters handle the packet forwarding and so your messages find their way to INET pretty easily. So well now that most digipeater controllers only handle two hop packets and most packets find an INET gate on the second hop. There's no need to clog multiple digipeaters with packets, you just need to hit one and your packet will get there.

Think of APRS packets more like cell towers than point-to-point, since we all run on 144.390 it could be a couple of seconds of bouncing around before your packet hits it's final destination. That's why most all-in-one APRS trackers are 10W or less, they let the repeaters do the work and then don't eat batteries as fast. Really, there is nothing to be afraid of with repeaters. It's not that life's too short for QRP, it's life's too short for VHF simplex.

I think the most important thing with APRS is use an external antenna, more so than 5W, 10W or 50W.

wesintl 07-27-2011 03:56 PM

Quote:

Originally Posted by DaveInDenver (Post 188044)
If you're trying to reliably get into aprs.fi in the backcountry, more power is probably good

I've been alot of places where you can't hit the digipeater and I've also hit at over 120miles.

anyway, one thing i really loath is that if you can't connect to the digipeater your packet is gone. If it can't connect if should store the packet until it can.


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