[HamWAN PSDR] HamWan 900 MHz

[Steve]

I tried using the Canopy system at 900mhz. Just three miles, nada. Canopy
is wide band, but I still expected a link. Then I looked at the spectrum
and it was BAD in downtown.

Steve


On Thu, May 23, 2019 at 11:03 AM Bart Kus <me at bartk.us> wrote:

> To back up my claims of low noise floor, here's 5 minutes of airtime
> sampled from a 900MHz antenna @ Haystack, aimed roughly at Everett (287
> degrees):
>
>
>
> I don't use this system anymore, so I'm making it available for HamWAN
> experimentation for the next few weeks/months.  To use it:
>
> Modem: Rocket M900 / M9, or compatible, dual-polarity MIMO.
> Antenna: https://www.ui.com/airmax/airmax-yagi-antenna/
> SSID: HamWAN
> Frequency: 917MHz
> Bandwidth: 5MHz
> Mode: AirMAX TDMA
> Security: None
> IP: DHCP
>
> Please let me know if you're attempting to connect, regardless of success
> or failure, as both results are useful.
>
>
> --Bart
>
>
>
> On 5/23/2019 10:16 AM, Bart Kus wrote:
>
> Another thing to mention about 900MHz usage is that it's very close to
> really powerful paging / cell systems.  We had to use an 8-cavity
> super-narrow bandpass filter to make the 900MHz installation @ Gold Mtn
> work.  The initial deploy didn't use said filter, and the adjacent QRM was
> so bad that I couldn't even connect to the AP from the base of the tower!
> I have several more filters in stock to support any possible future site
> deployments.
>
> In my surveys, I haven't observed the high in-band noise floor that others
> are reporting.
>
> Due to the lower gain and directivity of 900MHz antennas, the signal
> levels are low, and higher power would be useful.  Sadly, 900MHz
> bidirectional amplifiers are still prohibitively expensive.  If I recall
> correctly, the math models I did for 900MHz mobile coverage required
> something like 500W peak amplifier performance to get decent data rates.
>
> Sad to hear about the EOL of the 9HPn.  :(  In light of that news, it
> probably makes sense to re-work that system with available gear, such as
> UBNT.
>
> --Bart
>
>
> On 5/23/2019 10:03 AM, Bryan Fields wrote:
>
> On 5/23/19 12:57 PM, Steve wrote:
>
> The 900 MHz noise floor is pretty bad around the populated areas. Lots of
> utility's use it now.
>
> The narrower the better.
>
> If it's just a ptp use, a M2 yagi will help.
>
> Also, there are radios from the mid 2000's mabe by alvarion:
> https://www.ebay.com/itm/162895142474
> They are a 2 mhz channel and will do about 1.5 Mbit/s and 550 packets/sec.
> It's not a lot but if it's behind trees, it's just fine for a link or a
> few
> phones.
>
> 73's
>
>
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-- 
Pardon the brevity, sent from a mobile device.
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