I don't know the answer to that question. I have always pondered the issue
of fade margin on digital paths. If you factor in an error checking in both
the modulation methods and the TCPIP stack, you can deal with minor fades
and in many cases you might not even notice a short fade. At that point
however you would still need to have a tool that deals well with temperature
inversions and rain fade, because if you do get a fade in those situations
it more than likely will last long enough to be noticed even on a digital
path. But in most cases for WISP's in today's usage patterns they won't run
in to those situations. The one thing that will start to push us back to
engineering like analog paths, will be the migration towards net
applications that are a more constant demand on the pipe and not bursting in
nature. Things that would be sensitive to packet resends will start to show
a weak backhaul with fading issues.



Thank You,
Brian Webster

-----Original Message-----
From: Chuck McCown [mailto:[EMAIL PROTECTED]
Sent: Wednesday, August 06, 2008 10:58 AM
To: [EMAIL PROTECTED]; WISPA General List
Subject: Re: [WISPA] Pathloss 4


Most of the tools use the old AT&T long lines long haul and short haul
availbility factors that were generated for analog radios.
It is the opinion of some that digital radios do not need to need nearly  as
much fade margin as the old analogs.
I would have to say, that our experience with some 60 mile paths using
cyclones, I would have to agree with that opinion.
Does Pathloss have a different availability formula for digital modulation?

----- Original Message -----
From: "Brian Webster" <[EMAIL PROTECTED]>
To: "WISPA General List" <wireless@wispa.org>
Sent: Wednesday, August 06, 2008 8:49 AM
Subject: Re: [WISPA] Pathloss 4


> Chuck,
> I am probably one of the biggest supporters of Radio Mobile, love the
> software and agree with you. What Radio Mobile does not do well is things
> like reliability factors for  hot standby and if you build in diversity
> antennas. For most WISP's this is not an issue. To that end, Radio Mobile
> does do well because you can get 10 meter resolution terrain data and now
> with the working clutter model you can do pretty well with that if you buy
> the data (1 km resolution is free). Radio Mobile also has issues above a
> certain frequency due to the fact that the Longley Rice model does not
> work
> that high. One big drawback to any RF tool is the learning curve and your
> knowledge of the basic RF theory itself. Knowing the theory helps you to
> recognize what the software is doing and why you might get errors. Any of
> them have a time commitment to become proficient and then use the tool to
> it's full potential. But as you said, it's certainly much easier than
> doing
> it from paper maps counting contour lines :-) I wonder how many people on
> this this even know how to do that?
>
>
>
> Thank You,
> Brian Webster
>
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
> Behalf Of Chuck McCown - 3
> Sent: Wednesday, August 06, 2008 10:24 AM
> To: WISPA General List
> Subject: Re: [WISPA] Pathloss 4
>
>
> What can it do that Radio Mobile does not?
>
> I have been engineering microwave paths since 1978.  Back in the day it
> was
> curved path profile paper and counting elevation lines on a topo map.  I
> have used about a half dozen software products over the years, including
> the
> original on line version from ComSearch.  I have NEVER had a path perform
> worse than my estimation.  Many times the received signal strength was
> within 1 dB of prediction.  I consider myself a professional and I am a
> commercial carrier.
>
> So, what's so wonderful about pathloss?
>
> ----- Original Message -----
> From: "3-dB Networks" <[EMAIL PROTECTED]>
> To: "'WISPA General List'" <wireless@wispa.org>
> Sent: Wednesday, August 06, 2008 8:15 AM
> Subject: Re: [WISPA] Pathloss 4
>
>
>> -----Original Message-----
>> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
>> Behalf Of MichaelDavidLake
>> Sent: Wednesday, August 06, 2008 8:11 AM
>> To: WISPA General List
>> Subject: Re: [WISPA] Pathloss 4
>>
>> Daniel,   Most professionals use Pathloss..... Most if not all commercial
>> carriers use Pathloss.... I've been engineering Paths for 8 years and
>> swear
>> by it.  Its worth it....  Knowing how to use it properly is priceless.
>>
>> I'm not in here much any more because some of the members like to go
>> against
>> the grain and try to re-invent the wheel with their "profound knowledge"
>> and lack of experience.
>>
>> Pathloss is a winner.  I've used it over the yrs to design networks in
>> over
>> 10 major US markets. 100-400 paths per market.
>> Its a great product.  You will need to know how to use a GPS.  The
>> software
>> ( Pathlosss ) is a great tool but it should be used in coordination with
>> a
>> process of " eyes on/ hands on ".
>>
>> Nothing is more valuable than Driving the path and terrain to see what
>> the
>> software is showing you on paper.   The software isn't going to show
>> things
>> like new construction.  It isn't going to show you that 80' tree sitting
>> on
>> the highest terrain feature blocking your path with gear at 60' on the
>> tower/rooftop.
>>
>>
>> Mikey
>>
>>
>>
>> In a message dated 08/05/08 14:35:25 Eastern Daylight Time,
>> [EMAIL PROTECTED]
>> writes:
>> Anyone on the list using Pathloss 4?  Just trying to figure out if the
>> money
>>
>> is really worth it.
>>
>> Thanks!
>>
>> Daniel White
>> 3-dB Networks
>>
>>
>>
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