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Electrical engineer- telemetry question.
Posted: Wed Jul 18, 2007 12:14 am
by Paul Conway
looking through Tracker, Wildlife and Marshall websites your able to find technical data on thier reciever units. I suppose, though I didn't look, you can find the same on thier collars. Is anyone with an electrical, electronics background ambitious enough to take a look and explain the different numbers/differences between the units and technically compare them, in turn giving us layman a general understanding of the terms, thier meaning, and importance. For instance Sensistivity for tracker was -136 dbs, for Marshall it was -149 (for one of thier units, -151 for another) and for wildlife -150dbm(is this the same as db and is it measuring the same thing. Is Sensitivity important, how so and how do you compare the three numbers to each other, is it linear, exponential, etc. What about some of the other data. Well if anyone puts out the effort- THANKS. Marshall seem to list less technical info in terms of hard numbers than Wildlife and Tracker did. I ain't sayin, I'm just sayin

Paul Conway.
Posted: Wed Jul 18, 2007 1:59 am
by Buddyw
I sure don't have a good grasp of this concept, but having a Degree in Electronics you would think I should!! either way here is what little I do know. It's getting into logrithmic equations.. I quit math at alegebra! (I took two days of Calc.. and decided very quickly that that was going to hurt so I cut my lass)
Someone correct me if I"m wrong, I'll ask a guy I know to check my numbers.
DB is basically the gain of a signal.
Let's say for example your collar puts out 5 watts like a CB radio..This is not correct.. I think the output is allot less (in the range of 10milliWatts if I remember right).
Antenna's and distance would probably be the biggest power loss for the signals.
At (I was wrong last night on my numbers last night.. this is round two.. They could still be wrong !!)
-3db equals Half the power. 5 X 1/2 = 2.5Watts
-6db eguals 1/4 the power. 5 x 1/4 = 1.5 Watts
-9db equals 1/8 the power. 5 x 1/8 = 0.625 Watts
Etc. etc.
I'm assuming(you know what they say about assumptions!) the numbers you are reading are related what the box is able to amplify.. Meaning a smaller (larger negative number) would be better...
All the collars are regulated by the same power requirments, so what comes into play are the Antenna's used and the ability of the amplifier to amplify the correct signal.. While leaving the millions of other signals alone.
Antenna's are a huge part of the equation. I would rather have a good antenna, and a crappy box then a Great box with a Crappy antenna.
That's just a shot from what little I know about it. I would hope that someone with more experience could help answer some of this.
But trust me all that is out the window as soon as you let the dogs go!
Posted: Fri Jul 20, 2007 11:33 pm
by Paul Conway
So for all we know about telemetry and all we state about telemetry there sure seems to be a lot we don't know (me included for sure) ???
thanks for your info Buddy. Paul Conway.
Signal clarity
Posted: Wed Jul 25, 2007 1:05 pm
by matt c
Another large part that has not yet been mentioned is signal quality. The clearer the signal the better the range as less noise is being transmitted.
This is regulated by the quality of the quartz crystal oscillator, the higher the quality of the crystal equals a cleaner signal going to the antenna. Have you ever had a collar that just doesn't seem to tune well to your box? Crappy crystal!
US manufactured crystals tend to be a much higher quality than thier Chinese counterparts mainly due to the fact that they have to be farmed in a class 3 clean room environment which allows no contamintion to be present.