PMP450-900MHz antenna question

Products PMP
1

Got a question for everyone.  We had more than a thousand customers on Canopy 900MHz gear in the past, still have about 200 of them.  The ones remaining are ones we have been unable to migrate to 3.65GHz, 2.4GHz ePMP, etc.  They're all on 17dB yagi antennas. (goes a long way toward explaining why we've not be able to upgrade them)

With the PTP450 in 900MHz there is a higher-gain 17dBish yagi available from KP Performance, but they're of course not exactly inexpensive.  Meanwhile we have about 300 17dB single-polarity Yagis in a pile behind the shop.

Has anyone tried mounting two of the older single-polarity Yagis together for the PMP450?  If so, what was the outcome?  Trying to find out if it's worth the trouble to create a custom mounting block to test this, and whether there's problems with cross-interference between the polarities, and if any such interference is mitigated by any particular efforts.  (like mounting closer together, farther apart, etc)

I just have trouble convincing the owner to buy 250 dual-polarity 17dB+ antennas at about $130 each.  If I can get a reasonable outcome with a couple hundred $15-$20 custom folded brackets that hold two (already on-hand and earmarked for recycling) antennas at +45 and -45 that would certainly be a win.

It's been disappointing that the official Cambium yagi for the 900MHz PMP450 gear is only 12dB, with the two standard antennas for the old Canopy gear being (IIRC) 14dB and 17dB.  Almost everyone who was on 14dB was already migrated to more modern and faster equipment years ago, and getting the last couple hundred off of the old 4Mbps-max-per-sector gear is essentially impossible without either new tower locations or $400+ per customer for new radios plus new higher-gain antennas.  (plus truck roll service call, and the majority are at least 50ft up in trees)  If I can shave $100/customer off that cost...

j

2

I don't know anyone that has standardized on this type of configuration. However, I know some folks have tried it, but not sure of the results.

I will send a note to Ben Royer, who has certainly done this sort of thing on the AP side. Maybe he has tried it on the SM side as well.

3

I indeed have done both. I’ll save you time and energy as we had over 1,500 Yagi’s we looked to put back into force.

Buy the Cambium or KP and move on.

The issue here is these antennas are designed to help mitigate localized noise issues. When we tried to cross two Yagis it took a minimum of 3’ separation for them to somewhat smooth out, but still showed signs of inconsistency. Not to mention not a lot of clients have the option to install antennas 3’ apart from each other.

If you do decide to test yourself, if you happen to have grid brackets laying around in the 100’s to 1,000’s also, take on and bend it at a 45 and this should give you the two planes you need for mounting the yagis.

4

Thanks, I suspected that would be the case but of course hoped otherwise.

j