Microstrip (flat panel) versus eliptical (disk) antenas?

[WirelessRudy]

@pe1chl

Of course it is easy to make an antenna that has low gain and narrow beam width: just take a high-gain antenna
and fit it with a wide band attenuator. You can easily obtain attenuators of e.g. 10dB or 20dB with N or SMA connectors,
and connect these inbetween your antenna and radio unit. (make sure you get a SHF-capable attenuator)

This will eliminate the overloading problem you get when using high gain antenna over a short path, but it will still
be a physically large antenna.

Yeah, and how to do that with an SXT? QRT? Sextant? DynaDish?

No, we know now, for small distance high focus beam with almost no side lobs and small antenna we have to go 60Ghz. Maybe Mikrotik jumps that train soon…

[sushilbiddu]

@WirelessRudy

@pe1chl

@docmarius

You just can not compare a 2 degree parabolic antenna with a 10 degree flat panel, even if the gains are similar.

But you normally will not find those, because gain is the inverse of beamwidth.
When the sidelobes are reasonably down relative to the main lobe, and when the manufacturer is honest (this is
often not true in the antenna business!), you can directly translate the beamwidth to the gain and vice-versa.

The only variable is the characteristics of the sidelobes. These are different for focussing antennas like the dish
and phased-array antennas like the flat panel. And for a dish they can be changed by adding the shroud that limits
the overspill from the feed over the edges of the dish.

So, what is it they do with these yagi antennas?
They are 2,4Ghz but the energy patterns aren’t that much different?

At times you need to bridge only some 10, 50 or 100 meters with 5Ghz where a big antenna would way to powerful but a low gain antenna picks a lot of noise. (and probably still is too powerful)

Actually I need a 1 or 2dBm radio coupled to a 5º or 10º beam antenna that is not bigger than lets say an SXT. It looks like in 5Ghz it is just not possible.

Go with yagi antenna dual chain. They are highly directive and take very less interference compared to dish and panel. Their signals travels in narrow beam.

[ste]

@WirelessRudy

@pe1chl; Very good explanation!

Still some questions though;

What happens if you for instance would make a metal tube the size of an SXT that is lets say 20, or 40 cm long (or unlimited length?)
Lets say you wan’t to cross a street of 40 meters with on both end a SXT. Put a metal tube of the dia of an SXT of 40 meters and on both end the SXT’s. What happens now?

In my simple mind all energy radiated will ultimately hit the other end? (Except for that part that actually is radiated to and towards the back.)
It will probably give a very distorted multipath receipt at the other end. (But 802.11n and ac like that?)
At the same time we will have almost 100% shielding against unwanted interference of foreign signals? Would this work?
And would there be a relation between this example of 100% tube coverage on the link compared to 0% tube on a standard SXT. Is there any formula for something like this?

I understand well narrow beam mean big size means high gain. But with the help of a deflector/shield (=tube?) could we not create a low gain narrow beam antenna? Like they sort of do with a tube enclosed yagi?

I also understand the higher frequency will be a solution maker here. The new 60Ghz technology will be usable but still on the expensive end.
We are in the process of ordering some 60Ghz backhauls though to cross 350 up to 450 meters. These I hope will get me out of interference issues and free some of my spectrum so my 5Ghz AP’s in the same band will be performing better too…

How do the Metrolinqs work for you? I know this is a MT Forum. But MT does not do 60GHz so should be no problem . We’ve some very short hops we want to use them and keep 5GHz free.

[WirelessRudy]

The Metrolinq’s are very good but still with some defects.
We have two complete links running; 1 x 348 and 1 x 655 meters.
It’s a new product and manufacturer is still working on the firmware, Landatel actually warns for that.
We have some issues with signal strengths were we should get more for the distance than the antennas actually show.
The 5Ghz build in backup is very unstable. And since we also don’t know what the device needs to fail over (well, if the 60Ghz fails its clear, 5Ghz should take over. But what in heavy rain the 60Ghz starts to fade to a very poor level? And how will it come back?) and the 5Ghz is 802.11ac without tdma we don’t use it but have our ‘old’ 5Ghz links as backup in ospf/bgp setup.

The original delivered brackets are not the best design. They are thin and although not bending they allow the antenna to vibrate slightly in the wind and since the 60Ghz has such narrow beam (some cm’s over hundreds of meters) it makes the signal become variable.
We are testing their new bracket (from manufacturer) and although much better still not 100% and not available yet in Europe as far as I have seen. We’ve got a set for trials.
(And its said to be an “extra” so expect to pay for each unit.)

When the links run we have a very stable, low latency, high capacity link. On the 655 meters I already managed to ‘pump’ almost a gigabit of aggregated (700 one way, 300 the other way) tcp data over it. (3 Netmetal sending/receiving at the same time to one CCR on the other end one one even further up the line.) One tcp stream only does 250Mbps!
During this test ping with big package was around 2-6ms with hardly any jumps higher up.
When pumping some 500Mb aggregated we had a very stable ping of 0-2ms with hardly ever one going over 3ms. (Took minutes to see one..)
On our daily traffic (some 40-80Mbps) we have an almost always 0-1ms latency…
And this link is not having the best bracket, so it vibrates a bit in the wind. It lacks some 20dB in signal according manufacturer and we see it fluctuate some 6dB’s…

But THE big issue is that each of the two links we’d use now are stalling every 1, 2 or 3 days. Biggest up-time is now 3 days and it needs a power cycle to bring it back. Not nice!

But since our original 5Ghz links in the heavy congested spectral performed soooo bad with poor speeds and latency in the order of 2-8ms with regular jumps into 40’s and 60’s we keep the metrolinq’s running and hope most clients will notice the improved quality were only some will notice the cuts. After installing the metrolinq’s on our main backbone (it had 2 Netmetals with 80Mhz wide channel. Capacity plenty but CCQ never better than 80% and latency of 4-8ms average and 40-60 max. Single tcp stream only 30-40Mbps…) we say an increase of client traffic of some 10% overall…

In the meantime I am on a daily basis communicating with the manufacturer to get their firmware’s sorted asap and the brackets improved. They are very helpful though so I have good hope they nail the important issues soon and then we have some excellent product!

One of the nice things is that we have now two links shooting from one tower with only some 20º angle in direction and 2,5meter vertical separation on the tower (=mast) and even in the same frequency they don’t ‘see’ each other! Try that with the best shielded and highest gain 5Ghz antennas. Even RF elements new simper line cones ‘see’ each-other.

MetroLinq announced a PtMP AP sector antenna as well which could be a nice alternative to the 5Ghz WISP industrie if they manage to get the problems solved and the price down…
(From a fiber connected AP bridge a couple of buildings with Gigabit speed over wireless! )

So yeah they work well but not reliable and works still needs to be done. But I did see in Landatel’s shop 40 or so available units were sold out in only 3 days… They just have a new lot in… you’d better hurry up to get them. I had to wait 5 weeks for the second link…

[ste]

@WirelessRudy

The Metrolinq’s are very good but still with some defects.
We have two complete links running; 1 x 348 and 1 x 655 meters.
It’s a new product and manufacturer is still working on the firmware, Landatel actually warns for that.
We have some issues with signal strengths were we should get more for the distance than the antennas actually show.
The 5Ghz build in backup is very unstable. And since we also don’t know what the device needs to fail over (well, if the 60Ghz fails its clear, 5Ghz should take over. But what in heavy rain the 60Ghz starts to fade to a very poor level? And how will it come back?) and the 5Ghz is 802.11ac without tdma we don’t use it but have our ‘old’ 5Ghz links as backup in ospf/bgp setup.

The original delivered brackets are not the best design. They are thin and although not bending they allow the antenna to vibrate slightly in the wind and since the 60Ghz has such narrow beam (some cm’s over hundreds of meters) it makes the signal become variable.
We are testing their new bracket (from manufacturer) and although much better still not 100% and not available yet in Europe as far as I have seen. We’ve got a set for trials.
(And its said to be an “extra” so expect to pay for each unit.)

When the links run we have a very stable, low latency, high capacity link. On the 655 meters I already managed to ‘pump’ almost a gigabit of aggregated (700 one way, 300 the other way) tcp data over it. (3 Netmetal sending/receiving at the same time to one CCR on the other end one one even further up the line.) One tcp stream only does 250Mbps!
During this test ping with big package was around 2-6ms with hardly any jumps higher up.
When pumping some 500Mb aggregated we had a very stable ping of 0-2ms with hardly ever one going over 3ms. (Took minutes to see one..)
On our daily traffic (some 40-80Mbps) we have an almost always 0-1ms latency…
And this link is not having the best bracket, so it vibrates a bit in the wind. It lacks some 20dB in signal according manufacturer and we see it fluctuate some 6dB’s…

But THE big issue is that each of the two links we’d use now are stalling every 1, 2 or 3 days. Biggest up-time is now 3 days and it needs a power cycle to bring it back. Not nice!

But since our original 5Ghz links in the heavy congested spectral performed soooo bad with poor speeds and latency in the order of 2-8ms with regular jumps into 40’s and 60’s we keep the metrolinq’s running and hope most clients will notice the improved quality were only some will notice the cuts. After installing the metrolinq’s on our main backbone (it had 2 Netmetals with 80Mhz wide channel. Capacity plenty but CCQ never better than 80% and latency of 4-8ms average and 40-60 max. Single tcp stream only 30-40Mbps…) we say an increase of client traffic of some 10% overall…

In the meantime I am on a daily basis communicating with the manufacturer to get their firmware’s sorted asap and the brackets improved. They are very helpful though so I have good hope they nail the important issues soon and then we have some excellent product!

One of the nice things is that we have now two links shooting from one tower with only some 20º angle in direction and 2,5meter vertical separation on the tower (=mast) and even in the same frequency they don’t ‘see’ each other! Try that with the best shielded and highest gain 5Ghz antennas. Even RF elements new simper line cones ‘see’ each-other.

MetroLinq announced a PtMP AP sector antenna as well which could be a nice alternative to the 5Ghz WISP industrie if they manage to get the problems solved and the price down…
(From a fiber connected AP bridge a couple of buildings with Gigabit speed over wireless! )

So yeah they work well but not reliable and works still needs to be done. But I did see in Landatel’s shop 40 or so available units were sold out in only 3 days… They just have a new lot in… you’d better hurry up to get them. I had to wait 5 weeks for the second link…

Thanks.
Hey @MT you could do this better ).