[HamWAN PSDR] VOTE: 900MHz service experiment

Bart Kus me at bartk.us
Sun Mar 8 12:30:58 PDT 2015


I didn't go, nor would I trust HamWAN money to sketchy antennas.

I purchased the 3 modems recently approved (1 replacement 5GHz and the 2 
900MHz modems) and saved money by combining shipping.  There is $118.12 
left in approved funds to get a 900MHz antenna solution. Baltic is 
asking for *$204.59 to make the OD9-8 antenna happen* (shipping 
included).  Laird's lower gain antennas also have crazy high shipping 
costs, and they quickly approach isotropic gain.  I don't think it's a 
good idea to spend $125 on shipping for what was supposed to be a low 
cost / low performance test antenna. Longer-term, we would very likely 
employ a cross polarized MIMO system since bandwidth @ 900MHz is very 
limited and it's therefore important to maximize bit/Hz.  There is only 
one antenna on the market that I'm aware of that fits the bill: Ubiquiti 
AM-9M13.  It's a 13dBi 120 degree dual polarity sector.  I'm pretty sure 
they add the dBi from H+V polarizations to arrive at 13dBi, so it's 
probably 10dBi / polarization.  Still, 2dB better than the 8dBi OD9-8.  
This antenna is physically smaller, so the shipping is much cheaper. *It 
costs $278.36 shipped*.  We'll also need a pigtail cable to adapt from 
the RP-SMA terminals on the antenna to the N-male on the modem.

Now, there are a couple advantages to going this route:

1) We can re-use this antenna if we do deploy a 900MHz service since 
it's the only one I'm aware of that fits the bill.
2) The experimental phase can test both vertical and horizontal polarity 
performance independently by simply switching a cable.

So here's the modification:

1x Credit from removing OD9-8 = ($118.12)
1x Ubiquiti AM-9M13 @ $252.00/ea = $252.00
1x RP-SMA to N patch cable (1m) @ $9.95/ea = $9.95
1x NF-NF barrel adapter @ $4.25/ea = $4.25
1x Shipping @ $36.60 = $36.60

*Total additional funds requested: **$184.68*

If we don't end up doing a 900MHz service, or it doesn't use these 
components, we'll return or eBay the parts and credit the HamWAN balance.

--Bart



On 3/6/2015 7:59 PM, Tom Hayward wrote:
>
> Try the swap meet tomorrow?
>
> On Mar 6, 2015 7:55 PM, "Bart Kus" <me at bartk.us <mailto:me at bartk.us>> 
> wrote:
>
>     Turns out the shipping on that 8dBi vertical is $125.
>
>     I'm open to suggestions at this point.
>
>     --Bart
>
>
>     On 3/6/2015 11:23 AM, Bart Kus wrote:
>>     I just sent you all the relevant invoices.
>>
>>     Thanks, board!  I guess I'm placing all the orders now.
>>
>>     --Bart
>>
>>
>>     On 3/6/2015 11:19 AM, Cory (NQ1E) wrote:
>>>     Bart,
>>>
>>>     I also vote YAY on the contingency that you get caught up on the
>>>     paperwork.  I still don't have the invoices on file from your
>>>     last two purchases. ;)
>>>
>>>     That makes it unanimous, so I guess the voting is complete.
>>>
>>>     -Cory
>>>     NQ1E
>>>
>>>     On Fri, Mar 6, 2015 at 10:49 AM, Ryan Elliott Turner
>>>     <ryan.e.t at gmail.com <mailto:ryan.e.t at gmail.com>> wrote:
>>>
>>>         Thanks, Bart. I vote yay.
>>>
>>>         On Fri, Mar 6, 2015 at 12:47 PM, gary.k7ek at yahoo.com
>>>         <mailto:gary.k7ek at yahoo.com> <gary.k7ek at yahoo.com
>>>         <mailto:gary.k7ek at yahoo.com>> wrote:
>>>
>>>             I'd be interested in experimenting with 900 mhz gear at
>>>             my Spanaway residence, and possibly at my Graham Hill
>>>             repeater site. I believe 900 mhz would provide better
>>>             overall results than 5 Ghz, which proved to be marginal
>>>             to barely usable during our recent site survey.
>>>
>>>             Best regards,
>>>
>>>             Gary, K7EK
>>>
>>>
>>>             Sent from my Verizon Wireless 4G LTE Smartphone
>>>
>>>             ----- Reply message -----
>>>             From: "Bart Kus" <me at bartk.us <mailto:me at bartk.us>>
>>>             To: "Puget Sound Data Ring" <psdr at hamwan.org
>>>             <mailto:psdr at hamwan.org>>
>>>             Subject: [HamWAN PSDR] VOTE: 900MHz service experiment
>>>             Date: Fri, Mar 6, 2015 10:38
>>>
>>>             Hello,
>>>
>>>             5.9GHz is awesome when it works.  The speeds are great, and it carries
>>>             as far as the eye can see with very low ambient noise floor.  It does
>>>             however have problems when it needs to penetrate trees and buildings.
>>>             To alleviate this, I'd like HamWAN to offer a slower but deeper
>>>             penetrating 900MHz service.  900MHz is the lowest frequency ham band
>>>             without bandwidth or modulation rate restrictions.  Before we deploy a
>>>             full cell site, I'd like to get some real-world experience with 900MHz
>>>             penetration, propagation and ambient noise conditions.  Here's the
>>>             cheapest appropriate hardware we can use for this:
>>>
>>>             1x Vpol omni antenna @ $79.50/ea = $79.50
>>>             (http://www.balticnetworks.com/laird-antenna-omni-8dbi-900mhz-n-female-integrated.html)
>>>             2x 9HPn modem @ $108.00/ea = $216.00
>>>             (http://www.balticnetworks.com/mikrotik-metal-9hpn.html)
>>>             1x Shipping @ $UNKNOWN (quote not showing?!  Need to call them.) =
>>>             $40.00 ???
>>>
>>>             Total: $335.50
>>>
>>>             I already have a 900MHz high gain Yagi-Uda in my inventory and can use
>>>             that to do various field tests.  These can be directly compared against
>>>             5.9GHz performance since the gear will be deployed to one of our
>>>             existing 5.9GHz cell sites.  The results of such comparisons will give
>>>             us a good idea of how well 900MHz might do for HamWAN.
>>>
>>>             Disclaimer: These may not be the right modems or antennas for us
>>>             long-term.  A real deployment might use Ubiquiti Rocket M900 with their
>>>             sector antennas.  These Ubiquiti items are far more expensive though,
>>>             and their software doesn't integrate as easily into our network, so for
>>>             the purposes of the test I believe the set of hardware I proposed will
>>>             do well at deploying fast and keeping costs down.
>>>
>>>             NOTE: If both the votes are approved, I will combine shipping from
>>>             Baltic to save money.
>>>
>>>             --Bart
>>>
>>>             _______________________________________________
>>>             PSDR mailing list
>>>             PSDR at hamwan.org  <mailto:PSDR at hamwan.org>
>>>             http://mail.hamwan.net/mailman/listinfo/psdr
>>>
>>>
>>>             _______________________________________________
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>>>
>>>
>>>
>>>
>>>         -- 
>>>
>>>         Ryan Turner
>>>
>>>
>>>         _______________________________________________
>>>         PSDR mailing list
>>>         PSDR at hamwan.org <mailto:PSDR at hamwan.org>
>>>         http://mail.hamwan.net/mailman/listinfo/psdr
>>>
>>>
>>>
>>>
>>>     _______________________________________________
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>>>     PSDR at hamwan.org  <mailto:PSDR at hamwan.org>
>>>     http://mail.hamwan.net/mailman/listinfo/psdr
>>
>>
>>
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>
>
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