50 mile throughput

[Anonymous]

Using appropriate hardware at both ends, configured correctly, with good RF, etc... What is the expected throughput at 50 miles?

[lonnie]

We would expect at least 2.6 mbps, which is what we are now seeing at 32 miles. We have a -51 dB signal at that distance, and throughput is mainly all about signal (once you have the timing licked).

[Anonymous]

Being subject to FCC, not common sense rules, I'm looking at just under 20 DB fade margin. Although the signal will be strong (amped both ways), the actual sign/noise will be a bit weak.

Also, it's really just 45 miles, not 50. (like it matters).

[lonnie]

I think your typical 250 mW amp into a 24 dB grid is real close to the limit when you take into account cable and connector losses.

I would say 45 miles is very doable and you can expect in excess of 2 mbps. I can't say exactly, since we have not tested this distance yet. We obtained 2 mbps with the old StarLink at 52 miles and this is a more efficient protocol.

[Anonymous]

5.8 gig rules in the US allow unlimited gain for P2P shots. Well, I should say ISM rules do. UNII rules have the same restrictions as 2.4 gig. Some have forgotten this, but it would allow MUCH higher gain when doing a 5.8 gig link over long distance.

Hope this cleared up why I was looking at a 5.8 upconverted link, instead of 2.4 gig.

[dkii]

The FCC Part 15 has a special clause for PTP links using directional antennas. As it states:

PtMP and omni applications:
1 Watt Max. transmitter output (30dbm)
If transmitting antennas of directional gain greater than 6 dBi
are used, the peak output power from the intentional radiator shall be
reduced by the amount in dB that the gain
of the antenna exceeds 6 dBi

For FIXED PTP utilizing directional antennas only:
1 Watt Max transmitter outout(30dbm)
The transmitter output must be reduced by *1*db for every 3db that the antenna gain exceeds 6db. Which, if my math is correct, says you can have a total EIRP of 48dbm(64 watts!!!!) with a 24db grid antenna

So.. with 250mw and antenna/cable losses(I figure 7db (3 connectors(1db each), lightning arrestor(at least 1db), and 50' of lmr400(3db)) is far from the FCC limit. And the more directional you get, the higher EIRP you are allowed. I saw a 36db antenna(13ft wide) on andrew's site 400W eirp holy mackerel!!! You could cook a hotdog in front of that thing :twisted:

Please refer to FCC Part 15.247 http://frwebgate.access.gpo.gov/cgi-bin/get-cfr.cgi?TITLE=47&PART=15&SECTION=247&YEAR=2001&TYP E=TEXT

Although as lonnie said earlier, you'd be amazed how far a very small amount of power will go when used with a properly designed system.

[Anonymous]

YDI has certified thier 2 foot, 27 db gain dishes and thier 250mw 2.4 <-> 5.8 converters with Lucent or orinoco cards. The converter is powered over the coax, so it sits right AT the antenna.

losses are really low because of this design.

It amps in both directions, providing additional signal level and somewhat more gain on receive.