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Old 12-07-2017, 8:48 PM
extan extan is offline
Join Date: Dec 2017
Posts: 7

Thank you all, very much, for your replies.

Apologies for my unclear description. When I speak of "PTT" I'm referring to push-to-talk (half-duplex) cellphones. I believe Nextel was first to market many years ago, but now ATT and Verizon offer it. It's my understanding that it's packet-switched, running over the data network. Last year the march used "AT&T Kyocera DuraXE 4G LTE E-PTT" and "AT&T Sonim XP5 4G LTE E-PTT". They were a complete failure, I assume primarily because the cell "towers" were completely overwhelmed by the extraordinarily high concentrations of cellphones. (I'm interested in any feedback on this assumption!)

We understand it's a very challenging environment for rf, but the march will go on, and we feel like we have to do the best we can with what we can get. That's what I'm hoping you guys can help us optimize.

I think we're talking about several dozen (maybe up to 60) handsets. These are non-technical volunteers divided into functional groups (eg medical, marshals, legal, stage/speakers, etc) that would like to be in close contact with others in the same group. Each group has a "head", and all the heads would constitute another group, facilitating inter-group communications. (I don't think it's practical to consider obtaining licenses, at least for this march, which is only about 6 weeks away.)

So it seems we are left with VHF/UHF with 2-way radios? I'm thinking if we could station a repeater on each leg of the route, ideally over the heads of the marchers, ideally within line of sight of the neighboring repeaters, it would offer significant benefit. Thoughts?

Perhaps we could park repeater-equipped cars along the route? Perhaps we could mount fairly tall antenna masts on the cars? Or would it be much better to try to find friends with offices directly overlooking the route?

It's not obvious to me what the primary sources of interference are. Is it all of the tightly-packed bodies? Is it rf noise from all the cellphones? Is it the buildings? Is it ambient noise from all the craziness of midtown?

We've had both the CP200 and XPR families recommended to us by rental houses...
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