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We have had a number of people write regarding amps and antennas.
I sat and did some calculations ( http://www.csgnetwork.com/antennaecalc.html ) .
With 79mW (stock) power from the node into a:
| 3.5dBi (stock rubber duck) |
.176W EIRP |
| 9dBi (yagi/omni/dish) |
.62W EIRP |
| 14dBi |
1.9W EIRP |
| 24dBi |
19.8W EIRP |
If you go with a 1/2W BDA (bi-directional amp--about $60-$80) into a:
| 3.5dBi (stock rubber duck) |
1.1W EIRP |
| 9dBi (yagi/omni/dish) |
3.9W EIRP |
| 14dBi |
12.6W EIRP |
| 24dBi |
126W EIRP |
And then, even a 2 watt BDA ($60-?00's ):
| 3.5dBi (stock rubber duck) |
4.47W EIRP |
| 9dBi (yagi/omni/dish) |
15.8W EIRP |
| 14dBi |
50.24W EIRP |
| 24dBi |
502.4W EIRP |
As you can see, no matter how many watts your pushing, having a better antenna ALWAYS helps out more than the amp, especially when you factor in cost.
I have seen a 25W BDA, for a couple thousand dollars, and drive that into a 3.5dBi Omni, your still only getting about 55W EIRP. (But that into a 24dBi dish will give you 6.2KW EIRP, enough to get fried pheasant/robin/bat/etc every night for dinner!-- If you cant hit your target with that, you must have too much dirt and concrete between sites.)
So your best bet will always be trying to connect with a good antenna first. If you connect, but its weak, THEN try an add a 100mW or a 1/2W BDA. Unless you like having dead birds on your property (already cooked!).
Dumping wattage into a weak antenna only propagates noise and makes things tougher for all.
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