300 yards with LOS with a signal of -70 dB?  That sure seems low.  You
either have another system real close or you have severe trouble with
antenna or cabling.  A Superpass 21 dB at that range would give you
-40 dB or better signals, assuming proper cabling.

Did you set the distance to a couple of miles?  I always figure out
the exact number and add 2 or 3 to it.  You can safely be over but to
be under limits throughput severely.


On 10/10/05, Tom DeReggi <[EMAIL PROTECTED]> wrote:
> I just installed a link using CM9, Station Server, WRAP board, about 300
> yards away LOS, with only a single client so far on AP to SU mode.  The
> radios associated at 54 mbps, and about -70 db, with a quality of 24/29.
> All speed enhancement features enable, and encryption turned off.
> Using Station server throughput test, testing from AP, the RX was 13.6 mbps,
> and the TX was 9.1 mbps.
> I thought that was odd, because I thought the TX would be faster. (AP to SU)
> This supported my estimates that 54 mbps Atheros card's top real throughput
> (for 54 mbps) was about 14 mbps, in a best case scenario.   Then through in
> longer range links, interference, hidden node (or CTS/RTS to cure),
> retransmissions, heavy use links, and before you know real throughput can be
> much less than 10 mbps.  Asumming of course Turbo Mode won't be used to hog
> up channels.
> My tech question is... Is this being limited by the Atheros chipset, or the
> WRAP motherboard? If using the Mikrotik RB532 board with higher processing
> speed, can a single Atheros card transfer at a higher rate?
> For those interested....
> My business decission question is:
> 1) If Atheros can't go higher than 10 mbps in real world PtMP and...
> 2) Trango has fixed its short range packet loss problem (which they have)
> 3) Trango has new low pricing on Fox-D2 CPE (dropped $100 or so)
> 4) Trango has better testing tools
> 5) Trango avoids all the problems of 802.11 standard and home brew that cost
> ISPs aggrevations (accept large packets 1600b, pre-assembles, consistent
> availabilty, security, better remote management, ARQ, etc),
> What reason would there be to use anything but Trango broadband, even for
> small community projects?
> 802.11 Atheros gives you...
> 1) Mesh designs
> 2) Relay radio designs, multiple antennas/links per single unit, with only a
> $50 cost per radio card added.
> 3) HotSpot, compatible with laptops built-in config.
> 4) Built in VLAN switch, when used with Mikrotik RB532&daughter card.
> 5) OMNI support, when 6 sector design not needed.
> 6) One radio to stock, that supports ALL Freqs, for easy on the fly
> adaptabilty (pending antenna swap).
> #2 was good to reduce roof top colocation costs, by not needing to discuss
> the need to install two radios with a landlord for roof top approval.
> My recent interest, was for #4 and #5 for a small multi-building /
> multi-tenant complex.
> I reduce AP costs, by using only one AP w/ OMNI (OK for short range),
> apposed to Trango sector model. In a worse case scenario, where a Trango 60
> degree, would cover all MTUs based on edge of complex placement, Mikrotik
> 802.11 would still save about $400 on the AP side.  On the MTU side, I would
> normally pay $385 for 802.1q VLAN switch (24 port) for EACH building,
> apposed to $99 additional for Mikrotik RB daughter card (total of 9 ports
> including RB532).  Many complexes have less than 8 subscribers per building.
> But if we use an example of a 4 building project, the savings for a VLAN
> switch  would add up quick to around $1100, and adding simplicity with
> maintenance of only one device (the CPE/Router/VLAN combo) instead of two
> devices (VLAN switch and CPE Router).  It also reduces costs for remote
> reboot devices, as the Mikrotik has a hardware watch dog, where as a typical
> VLAN switch would not.  We use WDS to accomplish VLAN support.  We use VLAN
> support for several reasons.  1) it protects end users from seeing other end
> users for security. 2) It allows us to more easilly centrally bandwidth
> manage and route via VLAN (per customer), apposed to paying attention to IPs
> and MACs which may have the need to change over time, or may not be known in
> advance.   3) Prevents customer's misconfigurations from effecting other
> users' links or router configs. Because the traffic doesn't cross paths, it
> can't conflict. The misconfigured client only gets effected.
>  I will say, after all the time it has taken me to order, deploy, figure out
> how to configure, and wait for equipment stalling reocurring revenue, I'd
> argue I would have saved by just deploying Trango and VLAN switches to the
> project.
> Another problem, is that if VLAN is used, its no longer possible to use a
> Trango sector for both VLAN and non-VLAN customers at the same time, because
> large VLAN packets would get their would be no VLAN device on the Non-VLAN
> custoemrs to untag
> In summary...
> 1) If Trango would add a third external connector option to their 5830AP
> line, like the 900APs, it would drastically reduce the justification of home
> brew wifi, making it much more affordable to use Trango for these type
> projects.  It still wouldn't fix the VLAN cost reductions, but then again so
> what.
> Tom DeReggi
> RapidDSL & Wireless, Inc
> IntAirNet- Fixed Wireless Broadband

Lonnie Nunweiler
Valemount Networks Corporation
WISPA Wireless List: wireless@wispa.org


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