Brad,
Do you care to address my comments about F/D ratios and beam width? I
think that is more pertinent in mitigating interference than dish size.
If there is one qualified RF engineer in this group who can post a
single message here that is thought out about the issues around 11 GHz
dish size, F/D ratios, etc. then we can and should consider the
possibility of addressing this as a genuine concern of WISPA. If all we
have are people saying we should comment on this with no basis of RF
fact as to why we should comment then I will stand by my original
assertion that it is not an issue we will be addressing here.
Are you an engineer Brad? Do you know the actual facts concerning this
issue along with the outcomes of supporting or denying support to the
petition? I guess we should address this issue since it looks like we
are addressing the idea of addressing this over and over again. If this
issue is that important to you, Brad, then why don't you Chair this
effort yourself and convince us of what the issues are, what the RF
facts are supporting the issues and why and how we should comment as
WISPA. I am not trying to stop you from helping, quite the contrary. You
obviously feel strongly about this issue so please send us what you find
so we can make an informed decision on how best to proceed.
Scriv
Brad Belton wrote:
"... I am sure we could setup a committee to work on 11 GHz dish size
issues."
That's beginning to sound like congress, the true epitome of efficiency.
<sigh>
No, I do not believe a committee of engineers is required to study the issue
as the RF impact of smaller antennas is largely already known. The simple
question was what do we think about it and possibly should we as a group
comment on it.
Best,
Brad
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of John Scrivner
Sent: Friday, March 30, 2007 12:27 AM
To: WISPA General List
Subject: Re: [WISPA] FCC requests comment on smaller dishes for 11 GHz
The truth is we need qualified RF engineers to speak up if they are
here. It is my limited RF engineering knowledge which has always led me
to believe that F/D Ratio (Focal Length to Diameter Ratio) which
determines the beamwidth of the focused RF beam including the spread of
the spurious side lobes in microwave parabolic dish antenna systems. If
that is the case then the F/D ratio (not the diameter) should be the
root of the discussion. The truth is though that I am NOT an RF engineer
and therefore not truly qualified to make any genuine comment on the
issue until I hear more from engineers who know. If this group wants to
devote resources to this issue I am sure we could setup a committee to
work on 11 GHz dish size issues. I am just seeing this as a minor issue.
I am sorry to those out there who think this makes me short-sighted.
Scriv
Jack Unger wrote:
Brad,
I see how my original comment could have been misinterpreted. There
was an element of "I don't have time for this". Now that I've taken
the time (that I didn't have) and (hopefully) asked the right
questions, I think it's time for others to follow up if they feel it's
an important issue.
Personally, I'm not worried at this point about allowing smaller 11
GHz antennas. I don't think it's going to cause us any problems with
frequency availability. I think 11 GHz frequencies will be available
when they are needed. FiberTower's investors include American Tower,
Crown Castle and SpectraSite. I can't believe that those companies
would want to do anything to "screw up" either the availability of
frequencies or the sale of "vertical real estate" on their tower
properties.
Have a good day,
jack
Brad Belton wrote:
Hello Jack,
Good to see you're back on track with, IMO, a proper response to the
11GHz
question/concerns.
Your initial comment came off as who cares and we don't have time for
this.
John simply dittoed your comments, so what was the group left to
believe? I
apologize if I misunderstood your intent.
Your questions/response below illustrate the type of post I would have
expected from you in the first place.
Best,
Brad
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Jack Unger
Sent: Tuesday, March 27, 2007 1:33 AM
To: WISPA General List
Subject: Re: [WISPA] FCC requests comment on smaller dishes for 11 GHz
Brad,
I think you may be misquoting or misunderstanding me. No good can
come from that. Real questions need to be asked and need to be
correctly answered before we risk our reputation by filing comments
with the FCC that are technically incomplete or technically incorrect.
Here's a repost of my original post.
****************** Begin Original Post *********************************
It would be good to know the minimum required dish size now and the
changes that FiberTower is proposing before deciding what to do or say.
I'm not sure this dish-size issue would impact any WISPs so we may
want to ask ourselves if there are more important issues that we need
to be focusing on, given the limited time and resources that we have.
I think this is an issue that the licensed microwave vendors will
probably deal with adequately, without harming our interests. When we
decide to purchase a licensed 11 GHz link, we'd be buying it from
them anyway.
Finally, WISPA doesn't have an engineering staff that can adequately
analyze the technical implications and prepare an informed technical
response to submit to the FCC.
******************** End Original Post *********************************
NOWHERE did I say that the licensed frequency bands are not important
to WISPS. Licensed backhauls are very important to WISPs. WISPs
SHOULD use licensed backhauls wherever interference levels are high,
where reliability is crucial, where throughput needs are high, and/or
where full duplex links are needed.
NOWHERE did I say that the focus of the group should be limited to
unlicensed frequencies only.
TO BE CRYSTAL CLEAR, I will restate each original paragraph and I
will list the questions that each paragraph is implicitly asking.
****************************************************************************
***
PARAGRAPH 1 - "It would be good to know the minimum required dish
size now and the changes that FiberTower is proposing before deciding
what to do or say". In other words, we need to know the minimum dish
size now and we need to know what dish sizes FiberTower is proposing
before we can begin to understand if there is any affect on us and
before we can formulate our position.
QUESTION: SO WHAT ARE THOSE DISH SIZES NOW, BEFORE A RULES CHANGE AND
AFTER THE PROPOSED RULES CHANGE?
QUESTION: WHAT'S THE TRUE IMPACT, IF ANY, ON US IF THE FCC ALLOWS
SMALLER DISH SIZES TO BE USED?
QUESTION: ONCE WE UNDERSTAND THE TRUE IMPACT, IF ANY, WHAT POSITION
SHOULD WE TAKE BEFORE THE FCC?
****************************************************************************
**
PARAGRAPH 2 - "I'm not sure this dish-size issue would impact any
WISPs so we may want to ask ourselves if there are more important
issues that we need to be focusing on, given the limited time and
resources that we have".
QUESTION: DOES A REDUCTION IN DISH SIZE REALLY AFFECT US?
QUESTION: HOW DOES IT REALLY AFFECT US? ARE 11 GHz FREQUENCIES
CURRENTLY IN SHORT SUPPLY IN THE AREAS WHERE MOST WISPs OPERATE?
QUESTION: HAS ANY WISP EVER BEEN DENIED A LICENSE FOR AN 11 GHz
FREQUENCY? IF SO, WHERE? HOW OFTEN HAS THIS HAPPENED?
QUESTION: ARE THERE MORE IMPORTANT ISSUES BEFORE THE FCC THAT WE NEED
TO DEVOTE OUR TIME AND ENERGY TO? WHAT ARE THOSE ISSUES? WHITE SPACE?
WISPS AS AN INFORMATION SERVICE? FCC's BROADBAND SERVICES SURVEY?
CALEA? OTHERS??
****************************************************************************
*
PARAGRAPH 3 - "I think this is an issue that the licensed microwave
vendors will probably deal with adequately, without harming our
interests. When we decide to purchase a licensed 11 GHz link, we'd be
buying it from them anyway".
QUESTION - IF ALLOWING SMALLER DISH SIZES WAS GOING TO CREATE
INTERFERENCE PROBLEMS WOULDN'T THE COMPANIES THAT MAKE 11 GHz
EQUIPMENT BE AGAINST THE PROPOSED CHANGES BECAUSE THAT WOULD RESULT
IN THEM SELLING FEWER LICENSED 11 GHz LINKS AND HAVING HIGHER
CUSTOMER SUPPORT COSTS?
***************************************************************************
PARAGRAPH 4 - "Finally, WISPA doesn't have an engineering staff that
can adequately analyze the technical implications and prepare an
informed technical response to submit to the FCC".
QUESTION - DO WE HAVE THE ENGINEERING KNOWLEDGE TO REALLY KNOW WHAT
THE TRUE EFFECTS OF ALLOWING SMALLER DISH SIZES WILL BE?
QUESTION - A SMALLER ANTENNA WILL HAVE LARGER SIDELOBES. IS THIS
REALLY AN ISSUE OR ARE 11 GHz ANTENNAS NORMALLY MOUNTED WITH A FEW
FEET OF VERTICAL SEPARATION ANYWAY SO THAT A MARGINAL INCREASE IN
SIDELOBES WILL REALLY HAVE NO IMPACT ON ANYONE ELSE ANYWAY?
QUESTION - SHOULD THE FCC GIVE ANY WEIGHT OR CREDIBILITY TO OUR
OPINIONS AND OUR GUESSES OR SHOULD THEY ONLY GIVE WEIGHT TO REAL
ENGINEERING ANALYSIS?
QUESTION - WHO IN WISPA IS AN ENGINEER AND HAS ACTUALLY DESIGNED,
ENGINEERED, AND DEPLOYED A SIGNIFICANT NUMBER OF 11 GHz LINKS? SURELY
SOMEONE HAS... WHO IS THAT PERSON? WILL THEY STEP UP AND DO SOME REAL
ENGINEERING ANALYSIS FOR US ON THIS ISSUE?
QUESTION: WILL THAT ENGINEERING ANALYSIS SHOW THAT THERE IS ANY REAL
IMPACT TO OUR ABILITY TO OBTAIN AND USE LICENSED 11 GHz LINKS IF THE
FCC ALLOWS SMALLER ANTENNAS TO BE USED?
QUESTION: WILL ALLOWING SMALLER ANTENNAS ACTUALLY BENEFIT US BECAUSE
OUR COSTS TO DEPLOY LICENSED LINKS WILL BE LOWER? (SMALLER ANTENNAS
COST LESS TO BUY AND SMALLER ANTENNAS COST LESS TO MOUNT ON TOWERS).
***************************************************************************
That's it, Brad. Your help would be most appreciated to get real
answers. If I'm "off the mark" as you believed, that's OK with me as
long as it leads to an understanding of what the real issues are and
builds our credibility with the FCC, the manufacturers, and the
public at large. Real understanding benefits everybody.
Best Regards,
jack
Brad Belton wrote:
Agreed. Just getting caught up on some of my email readings and
strongly
believe Jack and John are off the mark here.
6GHz, 11GHz, 18GHz, 23GHz, 24GHz, 60GHz and 80-90GHz should all be
important
to us as a group. Any frequency that can be used by fixed wireless
operators should be important to the group.
For Jack and John to assume the focus as a group should be limited
to UL
frequencies is short sighted to say the least. Many operations, ours
included, are already utilizing licensed spectrum were we can.
Best,
Brad
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Tom DeReggi
Sent: Monday, March 26, 2007 2:10 PM
To: WISPA General List
Subject: Re: [WISPA] FCC requests comment on smaller dishes for 11 GHz
Anything related to 11Ghz, should be WISPs concern. It is my belief
that all serious unlicensed ISPs will at some point start to migrate to
Licensed
spectrums for backhauls. 11Ghz is one of the few upgrade options
available
for WISP's that designed their existing backhaul to 5.8Ghz
functionality. (meaning needing 4ft dish 11Ghz to reach equivellent
distances of 5.8Ghz
2ft
dish links, in practicality). There really aren't very many Long
range backhaul spectrum range options out there. Relaxing the rules
could
result
in the inabilty for many WISPs to obtain 11Ghz licenses, because of
unavailable spectrum, when they are ready to need it. A 2ft dish
beamwidth
(9-10 degrees) will cover the width of most of a small city at 10
miles. (Sorry I didn't do the Angle math yet). Compared to that of
4 ft dish beamwidths. As much as I'd like a 2 ft Dish, how would
that effect my future abilty to get a license? Thats an important
question. Fibertower wants 2ft dishes today because they are ready
to buy up the licenses
today.
Are the rest of the WISPs ready to buy the licenses today? How much
license
space is available still? I think some propogation data and current
saturation data (number of links / potential for more links) would
need to
be disclosed first to develop a relevant opinion. And how would the
rules
effect cost? Currently 11Ghz is significantly more expensive to
obtain because of dish size. If smaller more advanced dishes were
allowed, a 2ft dish that had the characteristics of 3-4ft dishes,
would those dishes be more expensive because of their unique better
characterisitcs? The truth
is, every provider would chose 11Ghz over 18Ghz, if they could get away
with
a smaller dish. It would likely lead to less use of 18Ghz and 23
Ghz. Is 18Ghz getting saturated? If so it would be relevent to allow
11Ghz to take
over the load. But I'd argue that 18Ghz should be near at capacity
before
11Ghz be allowed to be more leanent in antenna size.
The bigger fight for smaller antennas is to allow 6Ghz to be allowed to
use
4 ft dishes. 6ft dish requirement is insane. If 6Ghz was allowed to use
4ft
dished, it would then give another option for long range, (within a
realistic antenna size for roof tops), then justifying the allowance
for 11Ghz to have smaller antennas. The question is, why isn't
Fibertower
just
using 18Ghz in their applications? Can they prove that 18Ghz is to
limiting
or unavailable for them?
Tom DeReggi
RapidDSL & Wireless, Inc
IntAirNet- Fixed Wireless Broadband
John Scrivner wrote:
Thank you Jack. You said it better than I could have.
:-)
Scriv
Jack Unger wrote:
Dylan,
It would be good to know the minimum required dish size now and the
changes that FiberTower is proposing before deciding what to do or
say.
I'm not sure this dish-size issue would impact any WISPs so we may
want to ask ourselves if there are more important issues that we
need to be focusing on, given the limited time and resources that
we have.
I think this is an issue that the licensed microwave vendors will
probably deal with adequately, without harming our interests. When
we decide to purchase a licensed 11 GHz link, we'd be buying it
from them anyway.
Finally, WISPA dosn't have an engineering staff that can adequately
analyze the technical implications and prepare an informed
technical responese to submit to the FCC.
jack
Dylan Oliver wrote:
I recall some past discussion bemoaning the large dish sizes required
for
licensed links .. I just found this in the latest "Rural Spectrum
Scanner"
from Bennett Law (http://www.bennetlaw.com/rss.php?vol=13&issue=12).
Should
WISPA endorse this? I'm not familiar with the details of 11 GHz
regulation.
*FCC Seeks Comment on the Use of Smaller Antennas in the 11 GHz Band*
The FCC has released a *Public Notice* announcing that it has adopted
a *Notice
of Proposed Rulemaking* seeking comment on whether to permit the
installation of smaller antennas by Fixed Service (FS) operators
in the
10.7-11.7 GHz band. The FCC initiated the rulemaking pursuant to
a Petition
for Rulemaking filed by FiberTower, Inc., a wireless backhaul
provider,
proposing to change the technical parameters that would permit the
use of
smaller FS antennas with reduced mainbeam gain, increased
beamwidth, and
modified sidelobe suppression in the 11 GHz band. The FCC seeks
comment on
whether FiberTower, Inc.'s proposals would serve the public
interest by
facilitating the efficient use of the 11 GHz band while protecting
other
users in the band from interference due to the use of smaller
antennas. The
pleading cycle has not yet been established.
Best,
--
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