I thought the 2.4 SMs were in fact V/H because the slant patch
wouldn’t fit in the case? Am I remembering this wrong? There was a
whole thread about it.
*From:*Af [mailto:[email protected]] *On Behalf Of *Kurt Fankhauser
*Sent:* Tuesday, November 22, 2016 8:06 PM
*To:* [email protected]
*Subject:* Re: [AFMUG] Dual-slant 900mhz omni (for PMP450) ordering group
When did 450 start working with mixing Slant and Linear? Whats your
definition of working? Last time I tried running a 2.4ghz 450 AP with
a V/H Omni and the slant SM's they all would operate in Mimo-A mode
(instead of Mimo-B) which basically resulted in throughput being cut
in half. Or are you saying that it works because the product does run
in Mimo-A mode when it cant distinguish the chains? I guess for me I
would want to run in Mimo-B mode to get maximum throughput.
On Tue, Nov 22, 2016 at 7:41 PM, Ken Hohhof <[email protected]
<mailto:[email protected]>> wrote:
I would be very surprised if you couldn’t use the dual slant yagi
at the SM and a V/H sector or (shudder) omni at the AP. You could
open a ticket with Support or post on the Cambium community. But
if 2.4 and 3.65 can do it, why would 900 lack this capability?
Why would a Dalmatian not have spots?
*From:*Af [mailto:[email protected]
<mailto:[email protected]>] *On Behalf Of *George Skorup
*Sent:* Tuesday, November 22, 2016 5:19 PM
*To:* [email protected] <mailto:[email protected]>
*Subject:* Re: [AFMUG] Dual-slant 900mhz omni (for PMP450)
ordering group
It's not as simple as taking the slant adapter off of the Cambium
yagi. The adapter is threaded. You'll need slightly longer bolts
and nuts to convert it to H/V.
Ideally, I'd like to leave them as slant and get away with a H/V
omni during site conversions. Then there's no going back to the
customers after swapping to Cambium OEM slant sectors.
What we could do right now if we really wanted to, is use an Antel
h-pol and a separate v-pol omni like L-com/Hyperlink or something
like that. I know Ben Royer has done that. I think it was an MTI
diving board though, and whatever v-pol omni.
On 11/22/2016 4:56 PM, Mathew Howard wrote:
I'm pretty sure the 900mhz 450i can do the phase thing... the
3.65ghz PMP450 definitely can (the high gain integrated thing
is H/V, but all the other 3.65ghz is slant, so it does work),
so it'd seem pretty odd if these couldn't. I did do some
testing with mixing H/V and slant antennas, and it seemed to
work fine, but I didn't really do enough testing to know for
sure. It looks like you can change the Cambium yagis to H/V
pretty easily (theres a metal piece the holds the mount to the
antenna at a 45 degree angle, that looks to be removable...
haven't actually tried it though).
Tower loading is definitely a problem with these things... so
far all of our deployments have only been one or two sectors,
because we usually don't need nlos coverage in all directions
anyway, but I certainly wouldn't want four of them on most of
our towers. Itelite makes a little (closer to the size of a
normal 2.4ghz sector) 11dbi dual polarity H/V sector that
could somewhat help with that, if they work half way
decently... they're not exactly anywhere near the same quality
as the Cambium sectors, and I'm assuming they don't have good
enough F/B ratio to do frequency re-use, but they are nice and
small and I'm hoping they'll be usable for some stuff. We have
one of them up, but I haven't had time to do anything with it
yet, so I don't know how well it's going to work.
On Tue, Nov 22, 2016 at 1:45 PM, George Skorup
<[email protected] <mailto:[email protected]>> wrote:
The scenario I have at many 900 sites is >15-20 customers
using 4x90 ABAB on FSK. There is no other option. 900 is
the only thing that works. And I'm already using 16MHz.
The top of the band is hosed with paging. I might be able
to sneak a 5MHz channel in somewhere, but it will depend
on the site.
The next problem is tower loading. I already have four
sectors. Adding another four of the Cambium OEM is
unpossible. So if I can have an omni to get the site
converted to 450i, take the FSK sectors down and put 450i
sectors in their place and then take the omni down.
That Alpha is hugemongous, but is dual slant. The KP will
be H/V. So how would the SM handle being in a mixed H/V
and slant environment? Can the 900 450i do the phase thing?
The final problem which could make this a big waste of
money is the smart grid rollout that we will see in the
next year or two. If I get FSK speeds out of the 450i
after they turn it up, that's pretty much suicide.
I would club baby seals for some TVWS gear that works.
On 11/22/2016 9:12 AM, Kurt Fankhauser wrote:
You are wasting you time with omni's on 900mhz. So
your sacrificing a lot of gain to get 360 degree
coverage which in turn will result in higher overall
noise floor and lower signal when this 450 product
really starts to shine you need 25db+ SNR at the
client side to get the higher modulation connections.
So even if you got the Omni you'd going to be lucky to
get 8-10db SNR to the client which means your only
going to be running at 2x speed and getting 10mbps
download which will probably be intermittent. I had a
lot of omnis on FSK 900 and I can tell you that after
having used the cambium slant sector on 450 I am a
firm believer in sectors only for 900 from here on
out. I have connections that are 3-4 miles out running
10mhz channels and getting 40mbps down/10mbps up. You
will never get that with an Omni unless you have LOS
and if you have LOS then why aren't you using another
frequency band?
On Tue, Nov 22, 2016 at 2:03 AM, Colin Stanners
<[email protected] <mailto:[email protected]>> wrote:
I've been looking for dual-slant 900mhz omni
options that would allow lower-cost PMP450 900mhz
deployment on middle-of-the-woods towers where
there are only a small number of customers (and
low noise). I know that "omnis suck compared to
sectors", but having nothing at all sucks more.
Due to the difficulty of designing dual-slant
antennas and the small market, options are very few.
Commscope has the CH360QS, only 5dbi gain at
~900mhz... and it's a cellular base station omni
with all the fancy doodads: 1800-2200Mhz band that
WISPs can't use, internal GPS antenna, internal
diplexer, remote-controlled signal tilt on the
upper band, etc. At $3500 per antenna I hope that
it makes your breakfast too.
Alpha has the best design that I found at present,
the AW3464. ~7dbi gain
http://alphaantennas.com/products/small-cells/aw3464/
. It's ~$1200 USD which is still inexpensive
compared to any other NLOS options.
But currently those antennas cannot be bought - I
spoke with Crossover Distribution and Alpha, they
haven't received enough POs to make a production
run, need 50 orders at a bare minimum. So if
anyone else is really interested in one or more of
these antennas, ready to buy for sure if they are
available, e-mail me "If available, I will buy x
number of the Alpha AW3464 at $1200/USD each from
Crossover." and I'll make a list, once it hits 50+
antennas I'll speak with Crossover and see if it
can happen.
