[FADCA] re: 802.11b/g Operations

Sat, 15 Feb 2003 11:20:41 -0500 (Eastern Standard Time)

 Hello all i have been following this line  of thinking closely =0D
my thoughts is it may be ok in town were antennas can be placed on
commericial buildings =0D
around town but in the country you are lucky to find a tower that will le=
t=20
anything else be placed on it due to the liabality  clauses in there
insurance point  in beeing i had a cell tower company want to =0D
place a tower in my pasture  and i asked if they would allow me to  place=
 a
triband antenna at the 300 foot mark  they replied  there insurance would
not allow it  so guess what i have no tower in my pasture nor will i ever
have unless there can be amateur radio communications placed on it .=0D
another case in point is i have my direct tv  dish mounted at 55 feet on =
my
tower and in march =0D
it needs to be realigned due to the strong march winds in the open countr=
y
god knows i do like to experiment with things   but i personally feel tha=
t
for the long range flat  systems 6 meters would be the  choice  .=0D
 just some thoughts from  the country lol=0D
73 john ke4ini=0D
 =0D
-------Original Message-------=0D
 =0D
From: [email protected]=0D
Date: Saturday, February 15, 2003 07:34:20 AM=0D
To: [email protected]=0D
Subject: RE: [FADCA] re: 802.11b/g Operations=0D
 =0D
Rich, Paul/All=0D
 =0D
Thanks for the real world feedback on the link estimates. That link=0D
estimator URL does have a mechanism for adding in additional loss for tre=
es.=0D
We need to develop the "real world" loss fudge factors based on your=0D
personal experiences. That would allow us neophyte microwavers to be able=
 to=0D
make more realistic estimates.=0D
 =0D
I think Paul is also right on with his suggestions of 3.3. and 5.5 GHz as=
=0D
being better target frequencies. Locating or developing a good sources fo=
r a=0D
2.4 to 3.3 or 5.5 Transverter/Amp/LNA would allow using the low cost WiFi=
=0D
radios in those bands with higher power.=0D
 =0D
My initial effort is just to get familiar with setting up a wireless netw=
ork=0D
and then doing a little experimenting with external antennas. The great=0D
thing is the cost of the basic WiFi radios is reasonable enough to do thi=
s=0D
even if in the end they are throw away.=0D
 =0D
Thanks for the help.=0D
 =0D
Rick=0D
 =0D
 =0D
-----Original Message-----=0D
From: [email protected] [mailto:[email protected]]On=0D
Behalf Of Richard Garcia=0D
Sent: Friday, February 14, 2003 1803 PM=0D
To: [email protected]=0D
Subject: RE: [FADCA] re: 802.11b/g Operations=0D
 =0D
 =0D
I agree the link ranges are a bit optimistic. I work for a PCS provider s=
o=0D
1.9 Ghz is a daily routine for me and since I live in somewhat rural=0D
country I also get to play with 6 Ghz, I maintain part of a 12 hop Harris=
 MW=0D
system on 6 Ghz. Most PCS providers do not run more than 8-20 watts from =
a=0D
site and that is out of the amp. Take into account about 200ft of 1 5/8=0D
feedline and then a 18 DB antenna at about 150ft. Coverage in a ENGINEERE=
D=0D
system is about 3-4 mile radius, coverage on a clear channel is about dou=
ble=0D
that maybe a bit more. We often turn up new sites on a test channel at ni=
ght=0D
and have the site driven then turn it to a operational channel and drive =
it=0D
again when it is in service.=0D
 =0D
Granted a point to point link will have directional antennas, not a littl=
e=0D
handheld but the power is WAY lower than the average 16watts and I seriou=
sly=0D
doubt that we will be lucky enough to get 2 points very high in a emergen=
cy=0D
situation. Also remember that these are part 15 allocations, not a specif=
ic=0D
band that only one carrier uses and has very accurate RF control over.=0D
Co-Channel will be a very important case here to work with and the S/N wi=
ll=0D
reduce the range.=0D
 =0D
On 6 Ghz the average antenna height is between 100-140 ft. Usually divers=
ity=0D
with Primary at 140 and Diversity at 100 8ft Parabolic Dishes (ie Super H=
igh=0D
Gain). We are talking $50K+ radios here and a 30 mile hop is marginal, so=
=0D
much so we are relocating one to 15 miles. Granted 6 Ghz is much higher t=
han=0D
2.4 but the HSMM is looking at all bands above 900 Mhz, 5.8 is quite clos=
e.=0D
 =0D
I just got a commercial AP today I am going to play with it this weekend =
and=0D
see how well it works without the BDA. I got to do some climbing to get t=
he=0D
amp/antenna so I don't know when that will be. But believe me paths are=0D
going to be difficult to do unless you have some serious towers or mounti=
ans=0D
to work with. City folk out there will have better luck since trees are n=
ot=0D
a problem and a 12 story office or condo is easyer to get on after a=0D
disaster in a pinch than dealing with large tower corporations. Case in=0D
point one national tower company started requesting in November all tower=
=0D
climbing crews to submit a few pounds of paperwork for climbing approval.=
=0D
Requested is a Custom Designed Safety Handbook, certified training,=0D
insurance documents and BANK STATEMENTS!! just to start. If you thought=0D
tower access was bad last year hold on to the future!=0D
 =0D
My observations are seat of the pants granted but I deal with it all day=0D
long on frequencies VERY close to what we are talking about, it just come=
s=0D
second nature after so many years.=0D
 =0D
Rich K4GPS=0D
 =0D
 =0D
-----Original Message-----=0D
From: [email protected] [mailto:[email protected]]On=0D
Behalf Of Paul J. Toth-NA4AR=0D
Sent: Friday, February 14, 2003 4:02 PM=0D
To: [email protected]=0D
Subject: [FADCA] re: 802.11b/g Operations=0D
 =0D
 =0D
Rick and all....=0D
 =0D
The HSMM is working on a number of different aspects of using DSSS=0D
technology above 900 MHz for digital networking and communications. The=0D
hardware group is currently working on developing a recommended Hardware=0D
List for Radio Amateurs to build their systems around. The software group=
=0D
is focusing on networking issues, applications and insuring the security =
and=0D
integrity of the system while being in compliance with Part 97. ?The=0D
massive proliferation of 802.11b devices operating under Part 15 offers a=
=0D
particularly interesting challenge for Amateur Radio that we seldom see i=
n=0D
any of our other bands. There are also legal and regulatory issues to dea=
l=0D
with to make this effort whole.=0D
 =0D
Based on some experience in the commercial broadcast industry, I think th=
e=0D
range estimates Rick offered are a little optimistic, particuarly here in=
=0D
Florida with all dense foliage and Summertime sub-tropical downpours.=0D
Getting the antenna above the treeline is paramount for any microwave=0D
signal. "If you can see it, you can make the shot" was the philosophy we=0D
lived by in my Broadcast News days. I believe we will be lucky to achieve=
 a=0D
five mile (5 mi) footprint radius in many areas for local access (User to=
=0D
Access Point). This stuff just does not like trees! It is also worth=0D
noting the commercial WISPs are using cellular-like antenna arrays at the=
ir=0D
Access Points rather than omni-directional antennas. Better gain and=0D
rejection of unwanted signals. Point to point with two foot parabolic=0D
dishes, I look for fifteen miles. Using separate RX and TX antennas (whic=
h=0D
is possible with some Access Points, like Linksys, may enhance the hop=0D
distance a little. The key on the Point-to-Point stuff will be to get the=
=0D
antennas (and antenna-mounted ampifiers) up in the air between 170' and=0D
300'. The 5.7 GHz band may actually be better for backbone operations as=0D
802.11a will support connectivity up to 54 MBps.=0D
 =0D
While there is still some room for Part 97 in the 2.4 GHz band, I believe=
=0D
Amateur Radio's real future is in the 3.3 GHz band. There is virtually no=
=0D
Part 15 activity there at the present time to trashup the band. If we can=
=0D
stake a claim first, our ability to use some power (>100mW) may help dete=
r=0D
Part 15 activity. The 2.4 GHz band is seeing so much activity in many=0D
metropilitan areas and Californai it's hard to squeeze a signal in edgewi=
se.=0D
In fact, a 2.4 GHz Amateur Radio voice repeater in California was recentl=
y=0D
turned off because it couldn't deal with the interference from a nearby=0D
802.11b Access Point. The ARRL is investigating this situation.=0D
 =0D
One other point worth noting. In my presentation last Saturday at Orlando=
,=0D
I noted a third potential area for development and activity...the 'Last=0D
Mile" for EComm (or EmComm, if you prefer). These high speed links offer =
us=0D
the ability to do voice, video and data simultaneously, if we have the ri=
ght=0D
equipment on both ends of the link. That means a Red Cross Field Operatio=
n=0D
could have their telephones and computer data routed over the same link.=0D
This is something to look at for supporting hospitals during a disaster.=0D
 =0D
Thanks to Doug-KN4YT for his comments this morning about ESATCOM. Tying a=
ll=0D
this together with satellite links is the ultimate high speed wireless=0D
solution. Until then, bring on the HF Pactor station that can route=0D
messages to gateway stations.=0D
 =0D
73 de Paul-NA4AR=0D
ARRL HSMM Working Group=0D
 =0D
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