[HamWAN PSDR] HamWan 900 MHz

[Bart Kus]

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