garmin alpha

[Stilly bay]

interesting, I never gave it much thought before this thread. I guess if the satellite was the middle man, there really would be no range limit on the collar... Huh, the more you know.

[AspenBud]

Here is a general run down of how the Astro/Alpha units.

Basically there are three types of communications going on.  The collars have GPS, The Handheld has GPS, and then the Collar and Handheld have radio communication beween them.

The collars send their location over a MURS Band radio.. (Basically think VHF radio)

The Handhelds  Are also stand alone GPS units and they receive the collar VHF signals to find out where the Collar are located.   Then they show the Dog collar on the mapping screen.

So when something goes wrong and you see the ? for the dog or you are not tracking the dog  it's almost always caused by 1 of 3 things.
1.   Either the Dog lost it's GPS fix,   
   a.  Collar will single blink when it does not have GPS fix (NO GPS FIX)
   b.   Collar will double Blink when it have at least 4 satelites linked up  (GOOD GPS FIX)
  c.   Collar will Triple blink when it is tracking at least 7 satellites.   (BEST GPS FIX)

2.   Second issue is the Dog and HandHeld are too far apart or something is causing the VHF Signal problems, (common problems are the Black antenna on the collar breaking)

3. Lastly The HandHeld can loose the GPS fix and it's not able to calculate how far the Collar is from it. (It will still show the dog on the map).

I always ask folks which Error they get when they loose the dogs,  Did the screen say, dog Lost GPS,  Or Lost communication.  Because that is key to figuring out what is going on with them.

The Alpha is a bit different in that it still uses the Same MURS frequency, however it's a bit different in how the data is handled,  one is the Bursts are smaller so that you have have more dogs,  and secondly both the Unit and the Collar are both sending and receiving information unlike the Astros where only the Collars are sending information.. 

On the alpha units, The collar sends it's location in a short burst, and then listening for "commands"   from the handheld,    ie,  if the user wants to Shock, Tone, Change updates ect.  ect on the collar.   

In the End all of the data transferred on both the ASTRO and the ALPHA is always done over a 2 watt VHF radio,  Specifically on the MURS band.

Hopefully this helps

Thanks for the run down. This explains a lot of things I've seen over the last few years.

[Sportfury]

Pretty cool stuff. If I had my old shorthair back I might have really looked at purchasing the Alpha. With my wirehair she is close hunter and always checks in.