PMP450+CLIP vs PMP450b - Field Experiences

Hi, just wanted to post some experience with the 450b vs 450+CLIP changes currently at the moment.

Recently we did some comparisons and changes in our network where we used a 450+CLIP and then changed to a 450b. We have also run comparisons side by side vs a CLIP vs 450b unit.

On average we are seeing a 7 to 9dBm difference poorer on the 450b units with lower modulation rates on the 450b units. Some modulation rates dropped from 8X & 6X to 4X and 2X

So - do other WISPs out there have similar experiences - or is it just us?

We should be releasing official software for the 450b very soon (within a couple of days).  I would highly recommend updating to the latest software available for this, and trying to compare again.

The overall gain for these devices should be very close.

The 450 with a CLIP is a total of about 18 dBi (9 dBi for the patch, and 8 dBi additional for the CLIP).

The 450b is 17 dBi total gain.

They are within about 1 dBi of each other.  We did simliar testing near our facilities. I will see if we have some relevant data that we can post.

I would definetly check on firmware.  We saw similar occurances until we upgraded FW.  Now we see almost identical results.  The 8x/8x on clip and 8x/6x on B isn't too concerning as the technician was just field testing these, and in another screen shot it was 8x/8x on the B.


What software version is running on your 450b units?   We did ship with beta software, and as Matt says, we are hours and days away from releasing the official release.  However, the load we shipped with should have been good in this regard.   Let us know the version and we can go from there to see if there is something more to look at beyond just upgrading to the latest.

Wondering what you mean by upgrade the firmware?

The current verison on the Support Centre is 15.1.1

The firmware on the 450b is 15.1.2 beta version that was shipped.

Are you stating to change to 15.1.1 or wait until 15.1.2 is released?


When 15.1.2 is officiallly released (which, as Aaron says is only a couple of days away), I would highly recommend upgrading to that.  I will post here also when that gets released.

Upgraded to 15.1.2 on the SM - have seen no change in the signal stregth and no improvement on modulation.

Can confirm still around 6-7dBm worse than a 450+Clip in mostly all installations.

Nearer to the tower is ok as drops from 8X to 6X in most cases - however the real impact is further away where it drops from 6X to 4X or even down to 2X ... operating on a 40Mhz channel we see a drop from 100+ down to less than 50Mbps ... that might sound ok - but reduces customers on an AP as well as reduces our capacity to offer higher speed plans in the future.

Real life example - one house we have installed a 450b - house closer to AP and good line of sight  - installation good  - runs at 72.5dBm and 2X. The house beside that one has a 450+clip - further away, same line of sight - good install - runs at 65dBm and 6X. Roughly 2.5km from AP.

We have another 2 houses that are the same - similar results.

When we are installing them - we go back to the 450+Clip due to the poorer signal stregth.

As stated - when lined up and close they work good - give them some distance or angles to the AP - seems they drop in performance rapidly.

Still need to upgrade the rest of the network then the AP ... (currently 450i running 15.1.1) - so not sure if that has something to do with it. Will try to upgrade the entire network next few days.

Will post more after getting further screenshots and photos.

Still wondering if anyone else is seeing this or is it just us?

We also do not see a change after the update.

We also see  6-7dBm lower than a 450+clip

For you guys that are having these issues, I have a few questions.

1) What is your AP model and sector antenna type?

2) How high it is?

3) Do you have any downtilt? How much?

On the SM side, it should be noted that the 450b is a very narrow azimuth of ~15 degrees, and about 30 degrees in elevation, so the aiming of this is quite important to get right, and may be more sensitive than you are used to.

we are trying to figure out what's going on, because what you're describing should not be the case.


1) PMP 450m

2) 4656' approximately

3) 6°-7°

AP and SM is running 15.1.2

sm is at 4127' and alignment has been checked again this morning with help from earbud tone. distance from ap is 1.2 miles, ap eirp is  36dbm.

450 sm with clip yielded a receive power of -63, 450b receive power is -68 to -69.

I have done several tests between 450+clip and 450b to other sites and see a -3 to -7 difference on receive power.

Hope that gives you a little more information.     


Have sent some data in already, however is there any more updates on this? I am hesitent to continue to install these whilst the issue is unresolved.

Hardware or software?


We are seeing similar results with the 450b. With the new software patch and correct alignment we are seeing from 4 - 6db of a drop. We are also talking short distances from 1 to 3 miles. The 450b from what we see perform similar to a 450 without a clip. We are connecting these to existing access points that are tilted and directed to suit the existing customers.

We also will not purchase anymore 450b SMs until the issue is addressed.  We need the extra gain that is advertized.

We are still working on this. We have as yet been unable to reproduce these results.  If anyone is willing to send in a unit to us, we will ship a replacement to you.  Please email me directly:

matt @


I sent you an email about shipping back one of our 450b SMs

Also have reached out and sent an email.

I would like to ask anyone that believes their 450b is not performing to expectations to do the following.  This will tell us if we're chasing the right issue here.

  • Once 450b SM is registered, run 2-3 link tests from 450b SM GUI. To run link test go to : Tools >> Link Status and click Run Link Test

Figure 1 Example of Good Radio with healthy link.

  • Look at the Received Power levels for both V and H paths in Downlink as well as Uplink. (Highlighted lines in above screenshot).
  • If difference in received power levels between V pole and H pole shows delta greater than 12 dB, it can be a sign of bad hardware.

Example of Bad Radio with imbalanced Link:

If you see this condition, please open a ticket with support, and we will keep you up to date with a remedy as soon as possible.

I would also like to ask again if anyone following this thread has had good experiences with 450b.  Is it performing as expected? 

We recived an SM tested by cambium support.  After swaping our 450b out for that one our modulation impruved all the way up to 256-QAM up and down.  Our plain 450 + clip would only do 64-QAM down.

Strangely our good 450b still gets about 2-3 dBm less than our plain 450 + clip.  But the modulation is much better so I guess thats what matters.

We have tested and found a few good 450b SMs in the batch we recived.  1 out of the 5 we deployied worked as expected.  We have 70 more to test tho.  We will be contacting cambium support to return the defective units.

I love it when it's not a lemon

Hi Matt,

I have sent you an email regards recent tests.

Let me know if recieved ok.


We have received your email, and are still working this issue. Thank you.