Reverse H-pol and V-pol

I used a connectorized epmp 1000 and a external antenna that I believe had the h-pol and v-pol marked wrong. Instead of sending my guy up the top of the tower it is mounted on to cross the cables, is there a way to switch the ports in software so that h-pol is v-pol and the v-pol is then h-pol?

This should have no performance impact – the radios figure out which chain to link to which other chain.

That being said – you’d have to be aware when looking at things such as eAlign which show you Chain0 Chain1 that these labels aren’t accurate. However, as has been pointed out before, those connector names aren’t consistent or correct across different models of ePMP anyway.


when looking at the face of a e1k-csm the Hpol is the left, but as ninedd said it really doesnt matter as the radios figure it out for themselves hence the naming chain 0, chain 1. really just read as port0, port 1, port 2 etc.

but to answer your question directly, no there is no way to dictate which radio is which. mostly because its radio 1 and radio 2 that you are connecting to and it does not care which it is on the other end as the other radio will sort it out.

1 Like

Plus, on some of the ePMP Models, they are labeled inconsistently and incorrectly anyway. That is problematic when you’re trying to diagnose and fix a low chain on an AP, and ‘chain 0’ in eAlign isn’t the ‘chain 0’ labeled physically on the radio.

1 Like

it is labeled correctly but it should tell you which radio the chain is on and the outside should tell you which radio it is connected to which could change if the person plugging in the antenna leads swaps them around.
agreed it is frustrating when one chain is way our and your trying to solve it

I don’t think so. Some models of ePMP appear to have their chain connections incorrect INSIDE the radio. As in ‘Chain0’ on the case of the AP doesn’t appear to be connected to ‘Chain0’ of the radio subsystem.

1 Like

let me reiterate: chain is a software concept not hardware. it does not matter which chain a port is on as this is setup on boot/init.
I agree that the internal connection from the board to the port can be wrong, I know for a fact that the e3kL had the rp-sma connector physically soldered to the radio output so its impossible to get wrong internally but as to which radio is which there is no way of knowing even from looking at the board directly. so in this regard any label on the outside is correct and it is our thinking that is wrong as we do know know which chain should be H and which should be V.

from a troubleshooting point of view it is important to know which chain is currently on which port so that we can figure out what is going wrong with that individual chain and this is what I had asked for earlier.

Yes, I’m aware that the radios will figure it out, so that accidently crossing pigtails isn’t performance impacting. That’s why I said above:

I was just trying to point out the OP that he can’t be confident that the physical CH1 connector labeled by Cambium is the same as CH1 in the software when he’s troubleshooting… as shown in these eAlign results. It doesn’t matter if Cambium soldered them on… if the connector is physically labeled CH1 and that’s backwards in the eAlign software, then it’s still backwards.

1 Like

Sigh… not all this again :man_facepalming:t2:

1 Like

Eric - what does that mean?

Seems like every few months this question or something very similar gets asked and there’s a bunch of sparring back and forth regarding various aspects of this.

It’s all regarding a mix of these items:

  • Will mismatched chains work?

  • Physical labels for polarity being incorrect or confusing

  • Software labels for polarity being incorrect or confusing