we are setting up a PtP 70Km link, using the DBII miniPCI card and nv2. The card is MiMo, I will configure it in N mode. I will using 2 29dBi dish antennas.
Have you any advice for configuration/set-up?
How much throughput can I expect?
I am assuming 5.8Ghz
make sure you dont exceed EIRP for your region. In the US it is 53dB for a point to point link so your radios would have to be 24dBm or less. MAX antenna is 29dBm. That means radios no more than 24dBi. remember, if your radio link can fall to MCS0 and you are using default power levels, it could be up to 27dB! set radio up accordingly.
Next, be aware that your fresnel zone is going to be huge. Realistically, you will need 100m towers on both sides if the ground is level between them. If you are on hilltops then you can do less, but at the 35km midpoint your LoS line will need to be at about 100m to clear 60% of the fresnel zone.
These are very hard links to make because of how the fresnel zone balloons out at distance.
If the stars align for you and you have enough tower high and clean fresnel and your SNR is good, you might get 120Mb sync rate and 60Mb/s aggregate.
If you can't get enough height, then lower your modulation rate all the way down to MCS0 on the AP. Make sure you are passing as much traffic as possible over the link and watch the signal levels and the noise floor. You need 20dB SNR. bump up the MCS level by one and repeat the test until you cant without dropping below 20dB SNR.
Also, write down the sensitivity levels of your radio for each modulation. Use the worst number between the sensitivity and the noise floor (if the noise floor is -96 but the sensitivity is -85, then use -85).
I might even consider aiming for 24dB SNR because when you get weather fade it will effect very long links more.
Good luck and please post results!