UmTRX Digest, Vol 4, Issue 35
andreysviyaz at gmail.com
Mon Oct 29 09:32:17 UTC 2012
1) POE components still very expensive for 1GBe and -40 deg C.
2) We'll experiment with POE when 100MB will possible to use.
Anyway, it should be some sppecial design like nanoBTS, for example.
P.S. why issue 35?
2012/10/29 Alexander Chemeris <alexander.chemeris at gmail.com>
> On Sun, Oct 28, 2012 at 11:31 PM, Darby <darbysgoodies at gmail.com> wrote:
> > On Sun, Oct 28, 2012 at 12:26 PM, Alexander Chemeris
> > <alexander.chemeris at gmail.com> wrote:
> >> On Sun, Oct 28, 2012 at 10:08 PM, Darby <darbysgoodies at gmail.com>
> >>> On a side note, for power -Something that could come in useful since
> >>> its got ethernet, PoE?
> >> PoE is an option, but UmTRX require too much power for the standard
> >> PoE and we think that for lab usage PoE is an overkill.
> > Whats the total power budget? 802.3AF should be kosher with 13w at the
> > device, 802.3AT (PoE+) should be good up to a little over 20w
> > Im with you on the lab piece, Im just thinking of a seemingly
> > ubiquitous power source in a industrial environment -I bring this up
> > since so many industrial Wifi AP's (Gateworks, JJPlus, etc.) are PoE
> > powered
> According to our latest measurements, UmTRX alone requires ~15W:
> If you add UmSEL, it will add few Watts as well, but it should be
> below 20W I think. So PoE+ may be an option for a UmTRX without an
> external PA.
> When we discussed internally, we discarded embedded PoE for a couple of
> 1. We focused on medium-range cells which would need an external PA.
> And in this case we're out of PoE power range. In case of a pico-cell
> output power (50-200mW) we could do with PoE.
> 2. We decided that for the first iteration we'd better focus on more
> important issues and use an external PoE adapter if needed.
> 3. PoE by default has 58VDC output. We replaced all capacitors to
> tantalum ones and IIRC there was a concern that increasing input
> voltage range to 48VDC may considerably add to the BOM cost. This is
> according to my memories - I hope Andrey Sviyazov could correct me if
> I'm wrong.
> Taking all this into account, I think we might consider adding PoE
> option in some later version, but it's not a focus for us now. If
> someone wants to help us in adding this feature - please go ahead.
> It's an open-source project after all.
> >>>> 2. Enclosure. We'd love to have a nice table-top enclosure for UmTRX,
> >>>> but it requires a significant effort to source, design and assemble.
> >>> If anyone has some preexisting case designs, there's always protocase
> >>> (protocase.com) or Rapid sheet metal
> >>> (http://www.rapidsheetmetal.com/parts/enclosures.aspx) -Im sure theres
> >>> plenty of other sheetmetal fabshops that will do custom work though,
> >>> If youre wanting to use something a bit more generic -Theres
> >>> enclosurehub.com
> >> Interesting. Do you know similar ones in Europe? We manufacture in
> >> France and shipping enclosures from US doesn't look like a good idea.
> > Not that Im aware of, I know of protocase since they did the backblaze
> > storage pods & you can order anything from them in individual piece
> > quantities -But thats not to say that there arent plenty of others
> > that offer the same services, I would imagine there would be a fair
> > amount of places in europe that will do sheet metal enclosures -If you
> > want something extruded though, they might have a MoQ to make the cost
> > of the die fabrication feasible...?
> With 15W-20W power consumption Andrey Sviyazov is worried that a sheet
> metal enclosure might not be enough. I'm still inclined to give it a
> try for a lab enclosure, though.
> That said, we don't have manpower to do this right now. I estimate
> this as at least a week of work and thus as I mentioned - if someone
> is willing to make a design, we're ready to assist by all means.
> Alexander Chemeris.
> CEO, Fairwaves LLC / ООО УмРадио
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