05-13-2016 07:32 AM
My customer wants to use an AP-224 (he has exclusively 220-series APs), inside a building, cabled to an outdoor, dual-band antenna set, providing good-range omni-directional coverage. He therefore wants to deploy a kit of 3 x ANT-19. He wants lightning arrestors (I think LAR-1s are right), but these use N-type connectors. I believe 3 x AFC2DL60-00 would hook the AP to the arrestors, with 3 x AFCSJMTM-00 linking the arrestors to the Antenna pig-tails. Have I got the right connectors in the right places?
Is ANT-19 recommended for outdoor coverage (it certainly appears sufficiently 'element-proof').
Unfortunately, he also requires 3m of cable in the cable scheme, to get from his proposed indoor AP location, to the mounting location for the antennas. Would AP-CBL-1 have the right connectors to provide this extra length?
I have already suggested to the customer that AP-275 would seem a far simpler approach, but he wants costs for the more complex alternative, so I need to confirm it's OK, in principle, even if I don't recommend it. Any comment on the two? Any 3rd approach we've not thought of?
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05-13-2016 07:57 AM
You would be far better off purchasing an RP-SMA-based lightning arrestor than trying to put together a convoluted patch cable plan. The LARs have to be outside anyway. Once you know the gender ends of the lightning arrestor you plan to use, you can figure out which cables to use.
Note that that many connectors and long cables are going to drop the RF at least 3-6dB (or more if there's more connectors) which will cut the range of that AP's coverage/throughput in more than half. The reason we recommend the 275s outdoors is that not only are the 275s outdoor rated, but also have far more power ouput which can extend coverage out past 200m in many cases. Range with the 225 using the ANT-19s will be much much less.
Also note that the ANT-19s are not polarized, so those coupled with being outdoors and no multipath will be the equivalent of SISO speeds.
Sr. Techical Marketing Engineer
05-13-2016 08:24 AM
Many thanks for the feedback Jerrod - I didn't mention it in my original post, but I had already suggested to the customer that using RP-SMA arrestors might be better (I've not used them, but I know Terrawave RF gear is usually pretty good and they do appear to stock such a thing). Any alternatives you'd suggest...?
As it happens, I don't think my original suggestion would work anyway, would it, as AFCSJMTM-00 has an RP-SMA male connector, the same as the ANT-19 pigtail (?)
With the loss introduced by whichever combination of cables, arrestors etc. presumably we can partially compensate by increasing Tx power, provided we remain within permitted EIRP? I guess that doesn't account for the loss on Rx though, does it, as the clients will all be bog-basic mobile devices...
On your point about single-polarisation and lack of multipath, presumably if you went for such a solution, you'd be best using just the two antennas and then, only to provide traditional antenna diversity, rather than additional bandwidth through MIMO...?
05-13-2016 09:24 AM
Even at max power on the 225 (18dBm per chain or 23dBm 3x3 MRC, ignoring antenna gain), if you lose 6 due to connectors and cabling, you're now at 12dBm per chain or 17dBm 3x3 MRC, ignoring antenna gain). In addition to Tx loss, remember you lose that on the Rx side as well (your AP becomes 5-6dB more deaf). So both Tx range and Rx range decrease, regardless of what you do with the power. With a 275, we have 23dBm per chain, or 28dBm from the radio (ignoring antenna gain) and no RF losses. You can do the math on how much farther clients can hear and talk back to an AP when there's a 10dB difference.
Ventev/Terrawave products should be fine. Any M-to-M extension cabels would have to have a coupler between them, worth two connector pairs, which means more loss.
You still want every connector on an AP terminated, at least for the MRC gain (on the 3rd chain worth ~1.5dB). So you want to use three ANT-19s. Also, how are they planning on mounting the three ANT-19s? If wall mounted, they will have to build a standoff to get them away from a wall 6-18" ideally, and then some kind of proper separation distance between them as well. All that money they *think* they are saving by using an indoor AP is going to be spent on time and labor and materials costs trying to make the indoor AP.outdoor antenna solution work, when they could just do a simple AP-275 on the wall and be done.
Note they have to buy THREE lightning arrestors, not just one. and three of every cable they chose to extend. The cables and arrestors will be hundreds of dollars at least, and then the standofs and structs will be another couple hundred, and then 4-5x the time and labor costs. All of that for about 30% of the performance and range of a 275.
Sr. Techical Marketing Engineer