Sriram, that brings up my next question. The channel planning model for reuse is great for Idealtown, located on a flat plain where one can permit and build POPs on a tidy rectilinear grid. (This may be just west of Rolling Meadows). I wonder about the utility of channel reuse in say, Realtown, where the topology is quite bumpy, forestation is patchy, and the operator takes what he can get in the way of locations for POPs. This is pretty much my situation, and probably plenty of other folks’ too.
I’m trying to think of a broad rule set for channel planning in those conditions. For instance, I’m planning to expand into an area with existing structures (silos). In the attached image I’ve modeled coverage in Radio Mobile with an RSSI of –66dBm or better at the SM, assuming an ePMP AP/90°sector at power limit for max modulation and Force (25dBi) SMs (antenna pattern is just an omni for planning purposes). Max cell radius is 6km. This is over actual topology, of course, and using a publicly available ground cover (clutter) database, so it should be a pretty good prediction of which POP gets best signal to a given location. Each POP has its own color, with some reuse where it wouldn’t be confusing. (This is RM’s “combined cartesian” coverage, so there are plenty of locations where more than one POP can provide better than -66, but the POP with the strongest SS gets to put its color on the pixel.) Some of the POPs won’t want a full 4-sector deployment, but many, probably most, will. Am I better off, generally speaking, with the recommended 4-channel model, with two of the four channels on each POP (and the other two channels on the adjacent POP) than I am with the two channel model? And if so, would I just maintain the same azimuths for all of the POPs—e.g. channel A always at 0° and 180° and C at 90° and 270 ° on POPs 1,3, 5…, then channel B always at 0° and 180° and D at 90° and 270 ° on POPs 2,4,6…? Then maybe we could just leave out unnecessary AP quadrants on POPs where they weren’t going to do any good. Is there any reason to try the ABAB reuse model if four channels are available? Does the necessity of setting Frequency Reuse “Front” and “Back” go away in the ABCD model—and can anyone explain just what that’s doing? Whew. Oh, yeah—can you just software switch between the GPS timing signal on the (internal patch or) local GPS port and the signal on the Cat5/6 from a CMM, if you want that kind of redundancy? From: Af [mailto:af-bounces+grip=nbnworks....@afmug.com] On Behalf Of Sriram Chaturvedi via Af Sent: Thursday, September 25, 2014 5:45 PM To: That One Guy via Af Subject: Re: [AFMUG] Cambium Newbie Question Hi, Yes, the GPS chip comes with an internal patch antenna. The internal patch antenna is automatically disabled once you connect the external GPS antenna (and auto enables when you disconnect the external antenna). If you think the radio itself doesn't have clear LOS to the sky, then you can use the external antenna and place it elsewhere on the installation to get better LOS to the sky. There are a couple of documents on our support site (https://support.cambiumnetworks.com/files/epmp) you can read through that will help answer questions about ABAB deployment using ePMP. Thanks, Sriram _____ From: Af <af-bounces+sriram.chaturvedi=cambiumnetworks....@afmug.com> on behalf of That One Guy via Af <af@afmug.com> Sent: Thursday, September 25, 2014 4:36 PM To: af@afmug.com Subject: Re: [AFMUG] Cambium Newbie Question the APs come with an antenna for GPS, but its never been clear to me whether there is also an internal patch On Thu, Sep 25, 2014 at 4:31 PM, Jeremy Grip via Af <af@afmug.com> wrote: So would you be able to switch over to the onboard sync remotely? Do you need an antenna for each AP for using it? Do you think it’s as precise as using an CMM4 (or SyncPipe Deluxe w/Gig Injector) if not as robust? If all POPs are sync’d with same Up/Dn ratio and max cell distance and they’re talking to the same birds, is it pretty much the same? From: Af [mailto:af-bounces+grip <mailto:af-bounces%2Bgrip> =nbnworks....@afmug.com] On Behalf Of Adam Moffett via Af Sent: Thursday, September 25, 2014 2:55 PM To: af@afmug.com Subject: Re: [AFMUG] Cambium Newbie Question .....also the PMP100 SyncInjector from Packetflux ought to work with ePMP. You might want the gigE version, but in the real world with a mix of subscribers at different MCS levels I'm not sure how likely you are to exceed 100x100. The CMM4 is a much more rugged beast. It is expensive, but you are not likely to go back and wish you'd bought the cheap one. My plan is to hook up the internal GPS and have it available, but also to provide sync over power. Once you are using GPS sync to re-use channels it becomes critical that it's always working, so better to have two timing sources available IMO. They have built in GPS if youre on a budget, not sure why alot of people are so die hard against using it On Thu, Sep 25, 2014 at 12:56 PM, Jeremy Grip via Af <af@afmug.com> wrote: I’m looking at ePMP w/channel reuse from a cost-comparison standpoint. Trying to figure out how much I need to spend on GPS synch for a 4 AP/ 2 channel cluster. Does it need to be a CMM4? I will want to be synching multiple POPs… Jeremy Grip North Branch Networks,LLC -- All parts should go together without forcing. You must remember that the parts you are reassembling were disassembled by you. Therefore, if you can't get them together again, there must be a reason. By all means, do not use a hammer. -- IBM maintenance manual, 1925 -- All parts should go together without forcing. You must remember that the parts you are reassembling were disassembled by you. Therefore, if you can't get them together again, there must be a reason. By all means, do not use a hammer. -- IBM maintenance manual, 1925
