So, humor me. I'm no engineer, I've simply learned everything the hard
way with several concussions to show for it.
Without looking at a datasheet, going with the numbers Mike mentioned....
If the LTE needed a -75 for 64QAM, and the 450 needed a -67... let's say
the end signal was -73 for the sake of argument.
So the LTE will be at 64QAM, and let's say that brings the 450 down to
16QAM. 2 modulation jumps.
2 modulation jumps is often a 2-3 dB increase in tx power.
Given a 4x4, that's a given of 3dB over a 2x2 system, somebody tell me
if I'm wrong.
So you're picking up 3dB from the modulation drop on the 450, and
gaining 3dB from 4x4 on the LTE. That evens out, 0 sum.
I'm dense, where is this additional 10dB coming from? There's no channel
width change, no increase in receiver selectivity or sensitivity, no
reduction in thermal noise. Help me out, educate me.
--
Josh Reynolds
CIO, SPITwSPOTS
www.spitwspots.com
On 02/23/2015 04:40 AM, Patrick Leary wrote:
That's exactly what I'm trying to say, except that the-75 for QAM64
5/6 is not an LTE thing vs the 450; it just reflects the quality of
the components of the COMPACT vs the 450 or PW, etc.
TJ, tone does not come across well via email, especially as you don't
know me. I'm aggressive and challenging, but I'm not trying to be a
dick. I apologize if I come off that way. But, re the "silly WISP"
comment -- don't make the mistake in thinking I'm some piker trying to
sell into some space I don't understand. If there's a vendor person
alive that understands "WISPs" any better than I, I'd love to meet him
or her.
On Feb 23, 2015 6:15 AM, "Mike Hammett" <[email protected]
<mailto:[email protected]>> wrote:
No, it's a very important part. If LTE needs -75 for top 64QAM and
450 needs -67 for top 64QAM, that's an 8 dB difference in favor of
the LTE. 8 dB in the Tx power or 8 dB in the receive sensitivity
is 8 dB in the link budget. Then there's a few dB here and a few
dB there from different systems such as 4x4, HARQ, etc.
That said, that's assuming no interferer. I'd like to see how they
compare in an environment with a -80 interferer. As Ken has
pointed out a few times, one of 3650's "secret sauce" is that
nobody's there yet to make a ton of noise.
-----
Mike Hammett
Intelligent Computing Solutions
http://www.ics-il.com
<https://www.facebook.com/ICSIL><https://plus.google.com/+IntelligentComputingSolutionsDeKalb><https://www.linkedin.com/company/intelligent-computing-solutions><https://twitter.com/ICSIL>
------------------------------------------------------------------------
*From: *"Josh Reynolds" <[email protected]
<mailto:[email protected]>>
*To: *[email protected] <mailto:[email protected]>
*Sent: *Monday, February 23, 2015 5:43:41 AM
*Subject: *Re: [AFMUG] Grail or Gauntlet? ...or Maybe Just
"Powerpointware"?
Deviates from the point. The question remains -- was something
different between the two setups, such as: antennas or power levels?
--
Josh Reynolds
CIO, SPITwSPOTS
www.spitwspots.com <http://www.spitwspots.com>
On 02/23/2015 02:05 AM, Mike Hammett wrote:
But it changes how much signal is needed to be useful.
-----
Mike Hammett
Intelligent Computing Solutions
http://www.ics-il.com
<https://www.facebook.com/ICSIL><https://plus.google.com/+IntelligentComputingSolutionsDeKalb><https://www.linkedin.com/company/intelligent-computing-solutions><https://twitter.com/ICSIL>
------------------------------------------------------------------------
*From: *"Josh Reynolds" <[email protected]>
<mailto:[email protected]>
*To: *[email protected] <mailto:[email protected]>
*Sent: *Monday, February 23, 2015 1:19:51 AM
*Subject: *Re: [AFMUG] Grail or Gauntlet? ...or Maybe Just
"Powerpointware"?
Sensitivity does not change the power level of the received
signal.
--
Josh Reynolds
CIO, SPITwSPOTS
www.spitwspots.com <http://www.spitwspots.com>
On 02/22/2015 08:42 PM, Patrick Leary wrote:
...also, seriously. You any like it's even possible to
compute a link budget without accounting for sensitivity,
MIMO scheme etc. Thinking dBm and dBi are the only numbers
in the equation has me wondering how experienced you are
Adam. You do realize don't you it's impossible to
understand link budget without knowing a whole host of
things besides the output power and antenna gain?
On Feb 22, 2015 10:37 PM, "Adam Moffett"
<[email protected] <mailto:[email protected]>> wrote:
I read that quote before Patrick, and I am forced to
wonder if that individual was in the United States and
running at the correct (legal) power level. And I
wonder if he was comparing the naked 10dbi SM to a
15dbi wimax CPE. You could definitely get 10db more
by turning up the tx power all the way and using a
bigger antenna, and maybe you can do some electronic
magic to make a little more out of the signal you're
getting, but there's no magic that makes more db's
appear. If both systems started with the legal +40dbm
then how does one end up with 10db more at the CPE?
I'm a skeptic by nature.
Testing back to back between Cambium and Telrad
products on the same tower at the same azimuth, we
found an average of 10dB better RF levels with
Telrad’s equipment."
