Good day i have a link up to 18km with a clear line of site. Before we mount to the tower, the horn, feed cable for horn (30dbi ubnt dish ant) and radio were tested and paired 2 meters away tested. The problem is when we try to install the radio on the production location both of them cannot link. My config @ ap is 1x20 channel width, freq 5690, tx power 30, local ant gain 30. I wonder when im at base radio i can only scan my lower radio but cannot see radio’s from 8 to 10 km.
@romel – Have you utilized the designer here by chance?
If my memory is correct, 18km (~12 miles) was reported when I ran into a similar need (not similar connection issue) by Mimosa as being beyond the expected range.
Now, I know for fact there are longer than 18km links, but when I ran into the reported limits, I just went a different path due to other cost factors.
But — in a test PTP I did, if you have clear LOS, and there’s no large bodies of water in the mix, and there’s no interference on your chosen frequency, alignment will be the only thing left.
When you start getting distant, like 18km is, a tiny different in alignment will make or break that link.
If you didn’t use the designer, I would recommend setting your link there. It may show something in the mix that helps sort it out, and it may also show something that might have been overlooked in some way.
“technically” (on paper?) with the proper elevation, the link should work for you, but alignment will be key. For the test I did, I required 100’ (30m) on one side, and (75’) 23m on the other side to make a good link that also had LOS and Fresnel clearances.
(additional note) – if I reviewed the correct antenna you noted, it only has a 5deg beamwidth – this is VERY narrow RF zone to work with. I suspect alignment might be the issue)
In the US, 5690Mhz is a DFS channel and may be limited to 30dbm ERP. The radio may be adjusting the power to match the FCC rule.
Good point about being a DFS frequency. Additionally in that realm, the radios by design will also attempt to change frequency if anything is heard on DFS “channels”.
In USA… this table applies…
|Band||Frequency Range||Max EIRP (dBm)|
|5.4GHz||5470-5600 MHz 5650-5725 MHz||30|
The frequency noted is in the 30db max EIRP category. I am reasonably sure your configuration if used in USA would be out of compliance.
But — back to the issue of inability to get a link — If you have the ability to use different frequency, you might try those options too. In some cases, you’ll have a luxury of not being limited by co-channel user considerations, and also different frequencies have different EIRP limits too, perhaps to your advantage.
One last thing, while it might be a minuscule consideration, lower frequencies travel further than higher ones, so you may find a little, albeit tiny, difference going lower rather than higher in frequencies.
We’re all here to help! Keep us posted
Oh – one other thought —
In my experience, there have been cases where TOO MUCH TX power was the issue. You should also consider and test lowering your TX power.