<html>
<head>
<meta content="text/html; charset=windows-1252"
http-equiv="Content-Type">
</head>
<body bgcolor="#FFFFFF" text="#000000">
Are you sure a Mikrotik host board won't just run a 902MHz card like
the XR9? If it's possible, that'd allow us to keep the same
software stack we have right now, keep TDMA, and provide the MIMO
we're seeking. The other thing I'm curious about is the frequency
agility of the XR9. Does it support 2.5MHz/5MHz channels? What are
the quantization steps on its tuning ability? What is its tuning
range? Are there other 902MHz miniPCI(-e) cards on the market?<br>
<br>
I'd still like to see sectorization since it's hard to scale
otherwise. The band is 26MHz wide, which is enough for 5MHz
sectorization. Perhaps the sectorized spectrum can be arranged to
avoid the most likely/frequent users of this band, but I don't think
you're gonna have any luck by trying to comply 100%.<br>
<br>
If someone has any suggestions about other technologies, such as
CDMA spectrum sharing, I'd like to hear them. One of the things to
keep in mind about 902MHz HamWAN service is that it's aimed squarely
at mobile users. Can't assume high gain directional antennas at the
user terminal. I'd like to support things like whips on car
rooftops with near-continuous coverage as the car drives around.<br>
<br>
As some of you are aware, I'm not satisfied with the available power
levels for any of this equipment. Mobile stations will be behind
buildings and trees, at close to ground level. I'd like to bring
things up +20dB or so over stock (ie: 50W range). If you know of
any affordable 902MHz amplifiers that can be used with these radios,
let me know. The requirements are RF-sensed TX triggering from
signals as low as 100mW or so, bidirectional signal handling, about
a 1us TX/RX delay time, and linear amplification since these modems
use amplitude components to carry data. Running off a standard 12V
car power system would be a bonus. The combination of reduced
frequency and increased power ought to drive a far more available
service than we have with the 6GHz offering right now. However,
experiments can begin right now with just stock power levels to get
a better feel for propagation properties and noise levels of this
band.<br>
<br>
--Bart<br>
<br>
<br>
<div class="moz-cite-prefix">On 11/21/2014 10:34 AM, Ryan Elliott
Turner wrote:<br>
</div>
<blockquote
cite="mid:CACHX6g-Dv6mAWy+k399=9TjnEyuRyLYJmc-HWnNSpJP_bViu1A@mail.gmail.com"
type="cite">
<div dir="ltr">Hey folks,
<div><br>
</div>
<div>I'd love to get rolling on testing some 900 MHz gear here
in Memphis. I've got a few high-level questions about it,
though, and I'd love to find out what others have already
settled.</div>
<div><br>
</div>
<div>Do we want to do sectors and multiple channels? UBNT sells
a AM-9M13 that looks pretty slick; 120 degrees, 2x2 mimo; spec
sheet here: <a moz-do-not-send="true"
href="http://www.streakwave.com/mmSWAVE1/Video/AirMax900Sector_DS.pdf">http://www.streakwave.com/mmSWAVE1/Video/AirMax900Sector_DS.pdf</a></div>
<div><br>
</div>
<div>Mikrotik sells a metal 9hpn that's 27 dBm @ 11Mbps to 24dBm
@ 54 Mbps (500 mW transmitter), but that's single chain. From
what I read, dual chain MIMO mitigates about 3dBm of noise,
which may be worthwhile. These devices don't play nice between
vendors, though, and I think the preferred dual chain 900 mhz
device is the UBNT XR9. We'd lose TDMA by going with this but
gain another chain. Thoughts?</div>
<div><br>
</div>
<div>Apparently the ARRL band plan is pretty outdated and
unrecognized (<a moz-do-not-send="true"
href="http://www.aracc.org/33cm900mhz.pdf">http://www.aracc.org/33cm900mhz.pdf</a>
). Around here, we have an organization named SERA that has
specified a 900 MHz band plan; it is available at the
following URL: <a moz-do-not-send="true"
href="http://www.sera.org/pdf-files/SERA%20902%20MHz%20FUP.pdf">http://www.sera.org/pdf-files/SERA%20902%20MHz%20FUP.pdf</a></div>
<div>So, here we've got </div>
<div>
<ul>
<li>922<=f<928</li>
<li>910<=f<916 (it says ATV...)<br>
</li>
</ul>
<div>And that's it. So, if we were to sectorize, we don't even
have 3 channels to use here.</div>
<div><br>
</div>
<div>Thoughts? Looks to me like omni, TDMA, and single 5 MHz
channel (911-916?) is the best way to go for this.</div>
-- <br>
<div class="gmail_signature">
<p><font face="arial, helvetica, sans-serif">Ryan Turner</font></p>
</div>
</div>
</div>
<br>
<fieldset class="mimeAttachmentHeader"></fieldset>
<br>
<pre wrap="">_______________________________________________
PSDR mailing list
<a class="moz-txt-link-abbreviated" href="mailto:PSDR@hamwan.org">PSDR@hamwan.org</a>
<a class="moz-txt-link-freetext" href="http://mail.hamwan.org/mailman/listinfo/psdr_hamwan.org">http://mail.hamwan.org/mailman/listinfo/psdr_hamwan.org</a>
</pre>
</blockquote>
<br>
</body>
</html>