[HamWAN PSDR] HamWan 900 MHz

[Bart Kus]

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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