Hi all,
I'd like to know if exist 5ghz very low-loss waveguides for 15-30 meters.
Does someone use waveguide instead coax cable?

ew42 is rated 4.4 - 5.00GHz
ew52 is rated 5.6 - 6.25GHz.
ew63 (standard) is rated 5.85 - 7.1GHz (there are multiple models for just the high end band)

http://awapps.commscope.com/catalog/And ... px?id=1392
http://awapps.commscope.com/catalog/And ... px?id=1393
http://awapps.commscope.com/catalog/And ... px?id=1371

I use both ew52 and ew63 kinds for my mikrotik network. The ew63 works fine @ 5.8GHz. I have been able to run 5.1-5.5GHz across ew52 without issue. I suggest if you want 5.0-5.3GHz that you go with ew42, though I have not used it myself.

The main issue with waveguide is that it is expensive and, if done according to standard, should be pressurized with nitrogen. It can be fairly expensive after the pumps, connectors, antennas, flanges, grounding, tower installation, maintenance, etc. Retail priced ew63 can cost $35/ft or more. If you are planning to build a waveguide based network from scratch then you probably have enough money to not use mikrotik and go with licensed radios like Ceragon or Dragonwave. Or even if you aren't super-rich and considering it, it would probably be more cost-effective to just put the radios on the tower and accept needing tower climbs to replace them. Also, waveguide isn't literally or figuratively bulletproof. The spring we had two of our lines shot out at the top of the tower. We had to file a $10,000 insurance claim to have it replaced.

However, yes, it exists and works well on Mikrotik 802.11 based solutions.

Thanks Colebert, info very clear. Last question: if I have six radios on tower, I need six waveguides or is it possible to use one for all lines?

If you are planning to run in the same band then the answer is no.

The reason is that you are connecting six radios operating on the same frequency range all to the same cable. This is not much different than connecting radios back to back. They will burn each other out because the signal from the 5 other radios will be hitting each radio. OUCH!

Now, you could do something like this:

1. Run single ew52 line up tower.
2. Buy three port "circulator" (waveguide splitter)
3. Connect RB w/ XR5 operating at 5.1GHz to circulator port #1
4. Connect RB w/ XR5 operating at 5.5GHz to circulator port #2
5. Connect RB w/ XR5 operating at 5.8GHz to circulator port #3

And now the key point:

You would need to put BANDPASS filters in front of each radio that rejects the frequency from the other two radios. I have not ever actually done this but in theory it should work if you get the perfect filters and are centered exactly to the operating frequency and have very high and sharp out of band rejection. Even then it would be quite a trick.

The problem with this is finding the appropriate bandpass filters for each range. A 5.8GHz filter is easy enough to find (http://www.l-com.com/item.aspx?id=22184 works well but down't have a very sharp rejection pattern) but there other ranges are hard to find and, once again, you're talking about more money especially if you are getting them custom made.

Ultimately, putting six radios on one cable is probably going to be unworkable. Once again, the main advantages waveguide are in situations where:

1. All infrastructure is pre-existing (eliminate build-out cost) and you are trying to save tower climb costs or,
2. Radios need to be so high on tower that build-out cost is equal to running fiber & power
3. Radios are not rated for outdoor use (obviously not an issue here.)

............................................
And now the key point:

You would need to put BANDPASS filters in front of each radio that rejects the frequency from the other two radios. I have not ever actually done this but in theory it should work if you get the perfect filters and are centered exactly to the operating frequency and have very high and sharp out of band rejection. Even then it would be quite a trick.

The problem with this is finding the appropriate bandpass filters for each range. A 5.8GHz filter is easy enough to find (http://www.l-com.com/item.aspx?id=22184 works well but down't have a very sharp rejection pattern) but there other ranges are hard to find and, once again, you're talking about more money especially if you are getting them custom made..........................

With the bandpass filters even with quoted "Ultra Low Insertion Loss (0.5 dB nominal) & 150 MHz Bandwidth" what is the actual effective insertion loss, could it be like most other devices with similiar 0.5db quoted figure in practice results in 2-3db loss?

In my case, I didn't really care. I share a waveguide with 7GHz radios pushing +34dB. If I don't filter that out then my XR5s don't work right. Also, I'm working with 41.2dBi antennas so workcase of 3dB of insertion loss isn't going to move the needle for me.

However, in practice I'd say these filters aren't very bad. If I had the right equipment, I would test it myself. But l-com and hyperlink make pretty good stuff.

I also don't use jumper cables. I just have the RBs in an indoor case with pigtail. I put an N to N adapter on the pigtail then screw it in directly to the bandpass filter. So even if the filter is hurting me some I'm still saving the loss on the LMR400.

In my case, I didn't really care. I share a waveguide with 7GHz radios pushing +34dB. If I don't filter that out then my XR5s don't work right. Also, I'm working with 41.2dBi antennas so workcase of 3dB of insertion loss isn't going to move the needle for me.

However, in practice I'd say these filters aren't very bad. If I had the right equipment, I would test it myself. But l-com and hyperlink make pretty good stuff.

I also don't use jumper cables. I just have the RBs in an indoor case with pigtail. I put an N to N adapter on the pigtail then screw it in directly to the bandpass filter. So even if the filter is hurting me some I'm still saving the loss on the LMR400.

I recently used screening on one sector integrated AP and just a drop of 4db co-location interference from the other AP's has stopped my NV2 disconnects will do the rest and note the results, i aggree with you on not using LMR400 jumper cables there is a lot of loss inpractice when used.

Yes, the bandpass filters help in ways you would not think are necessary when planning everything out on paper.

We get so greedy and focused on dBs above all else but the reality of the situation is that the spectrum is basically a garbage dump out there. Just cutting down whats hitting our cheap $70 radios can greatly improve their performance even if there is an insertion loss here or there.

For two chain mimo radios?
I hope I need only single cable with special adapters, right?

I have not tried to mutliplex a single MIMO radio on one waveguide. Maybe could work if you ran one chain at 5.8 and another at 5.1. Running at the same frequency obviously would not work.

I actually need to test how well MIMO would work across two waveguides going to different polarities on the same antenna.

But I would NOT put multiple radios on the same waveguide. It will burn them out.

I think the key here is "15-30 meters." As Colebert said, unless this is preexisting, AND there are no other hardware items to purchase, then use it. If you are looking at a fresh install, I'd seriously reconsider going to waveguide.

You didn't mention the application. Is this point to point or multipoint? Antenna(s) that you are looking to connect?

This additional information will help us help you. It could be a simple answer to use coax if you are only going to use a 28db panel. Or it could be much cheaper to step up to a 1m dish and use coax, rather than install waveguide to a 28db grid.