Dears, I´m new user here, and I change my POPs of Staros V3 to MK ! In this case I need make the link of 73 Km but with non line of signal, and i think that use the XR9 or XR7, but I ca´nt if is possible because many montain that see bellow the pic of Motorla link estimator - only have ideia! - I´m studing this case, but need help of any experience users of MK and frequency radio and I like of know if this link is possible! I waint help of all.

ps: Sorry my bad english

Not possible.

It doesn't matter what brand of radio. NLOS does not mean that microwave signals will go through mountains or hills; they just flat will not. NLOS will only work for very short distances. Something like 1, 2, or 3km. So when thinking about a longer backhaul, you MUST have excellent LOS along with excellent fresnel zone clearance. And when links get over 15km you have to start adding height to compensate for the curvature of the earth. (Unless you belong to the flat earth society.)

Tom

Thanks all, Regards

It doesn't matter what brand of radio. NLOS does not mean that microwave signals will go through mountains or hills; they just flat will not. NLOS will only work for very short distances. Something like 1, 2, or 3km. So when thinking about a longer backhaul, you MUST have excellent LOS along with excellent fresnel zone clearance. And when links get over 15km you have to start adding height to compensate for the curvature of the earth. (Unless you belong to the flat earth society.)

Tom

We've got a 27km NLOS link using XR9 and 5MHz channel. There's an obstruction around the mid-point - but only ten meters or so higher than we'd need for true line of sight. Signals of around -70dBm at each end.

We've also done 5GHz NLOS up to 10km. You'd be surprised at how well 5GHz can reflect off rocky pastures.

HAHA, yes 5Ghz does reflect off rocky objects VERY well. We recently had major issues with a p-t-p link where one end had a rocky cliff behind it, the signal was going straight past the dish and reflecting off the cliff and going all over the place. We were getting -54 for about 90 degrees horizontal, and thats on a 3degree signal out of the dish!

Our solution was to turn the TX power down as low as we could and get it operating that way, works great now.

One thing to remember when using reflected signals, you will get a lot of retransmissions and you will get duplicate packets.

If you have the money, a Fluke Etherscope can identify the % of duplicate packets and cross talk. On some mesh networks I have built on campuses and at shipping yards, up to 40% of all the packets were retransmits, which is not ideal.

Hey Jon, How did you get on for 900Mhz licencing in NZ?

We have looked at 900Mhz but decided not to use it due to concerns over spending hours on the phone with RSM, only to have them change their mind and slap us with a $1200 fine.

Hey Jon, How did you get on for 900Mhz licencing in NZ?

We have looked at 900Mhz but decided not to use it due to concerns over spending hours on the phone with RSM, only to have them change their mind and slap us with a $1200 fine.

1. GURL SRD notice 2007 permits 1W EIRP in 921-929MHz
2. Magic happens with XR9 run slightly out of spec
3. 22dBm tx power + 2dB cable loss + 10dBi TX antenna = (guess what!?!)

FYI we are soon to have 915-921 open to 1W EIRP as RSM move STL links to more appropriate spectrum.

Nice,

I am going to have to read up on licencing for other areas of spectrum. I only know the 2.4Ghz, 5Ghz and 60Ghz rules as thats all we have used so far.

I have noticed a few stations are using 23/24Ghz STL links now, I guess they will all be moving to these with the move to digital transmission leaving 900Mhz free for other uses.