C5x Slant issue with RF Elements Horn


Could use some guidance. When pairing C5x with RFElements twistport adaptor and HG3-TP-S30 Horn, how is the correct setup for slant? When assembling C5x and twistport adaport, i can clearly select H-V or slant. When i choose slant and attach the horn antenna it aligns properly. But i think i should change Horn to slant aswell ? When dooing that the radio dont align with horn anymore.

Also changing horn to slant isent that well documented, by default it should be H-V but i can rotate it many different ways and not sure what is proper Slant.

So slant is the polarization of your radio, since the C5x has 2 polarization’s you effectively have 2 polarization’s: Horizontal/Vertical (H/V) and 45 degree. Unless your AP antenna supports and is using 45 degree slant then you should basically default to using Horizontal/Vertical, otherwise you will loose about 2-5 dB of signal strength.

I would check the RF Elements documentation about how to do slant with that horn. Basically it’s going to boil down to how you mount the C5x, you will want the radio tilted 45 degrees right or left from straight up and down. Any other amount of tilt will not be all that useful and 90 degrees to the right or left will leave you with an H/V polarization again. (Note, like many other radios, the C5x doesn’t care which of it’s “chains” is horizontal or vertical, just as long as they are receiving two signals that are 90 degrees out of polarization from each other)

Why are you using a 30 degree horn with a C5x?

Thanks for the reply.

For ap i am using A5x radio with HG3-TP-S60 horn to act as 60 deg sector. Clients will be C5x with HG3-TP-S30 horn. Idea behind horns was to reduce interference as much as possible. But its currently just testing phase and trying out new equipment. With that setup, is there any real gain to slant or i should just leave horns H-V settings as they come by default ?

In theory, there could be up to 3 dB less noise using 45 degree slant. But you have to setup every antenna in 45 degree slant that connects to a 45 degree slant AP otherwise you will be loosing out on 2-5 dB of signal.

Normal practice is if you have a very dense set of radios using frequencies nearby each other then you will run your PTP radios in 45 degree slant to reduce the noise a little bit. (You do the PTPs because there’s fewer of them to have to deal with)

If you are looking for better noise isolation why not work with RF Elements Starter Dish series or their Ultra Dish line (if you have the money for a $100 antenna for each of your radios)

I did some more reading and for me it seems that C5x comes by default in Dual Slant config, not Slant + H-W. So in this case ap should also be in slant settings.

Since i already have horns for both ap and client, how good / bad this combination is compared to when client would have dish antenna? Lets say distances is 1-5km.

You are right, I forgot about that. (Just make sure your RF Elements antenna for your AP is setup in Slant)

There are 3 issues that you will be dealing with using a 30 degree horn vs a dish antenna. I would argue that there would just be one or two benefits.


  1. Easy to align, you are going to have a 30 degree beamwidth to work with and practically no side lobes. This will make it super easy to point at the AP and align. This may also help with Thermal Inversion issues, though under 3 km you won’t see many.

  2. Side effect of the “no side lobes” noise to the sides and behind your antenna will be greatly mitigated.


  1. Noise, you have a 30 degree beamwidth both up/down and right/left. That means you are going to pick up noise that emanates from around, in-front and behind your AP much more greatly then with a smaller beamwidth antenna.

  2. Low Gain, as you get further away from your AP the 18 dB of the antenna will be an issue. If you have any significant amount of noise then as you get a lower SNR then your MCS will also decrease.

  3. Cost. IMO there are better antennas you can use your $150 on. Especially if you are trying to go 5km or more.

Thanks for the info. :slight_smile: Il test with horns and if results are not good then il switch client side to Dish antenna.

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Good luck man. It’s not the worst thing you can do and props for doing your research and trying to learn as much as you can before you get yourself into trouble.

Make sure you have Clear Line of Sight between your AP and your Clients, it will help you immensely. (By clear line of sight I mean no obstructions and your fresnel zone is as clear as you can make it as well)

I highly recommend this video in particular to explain. Inside Wireless: Fresnel Zones - YouTube

That said, RF Element’s whole Inside Wireless Video series is excellent and will help to explain a lot of the stuff I am not very good at. (They are also just excellent guys.)