On Thu, May 23, 2019 at 11:03 AM Bart Kus <me@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 ofIf it's just a ptp use, a M2 yagi will help.
utility's use it now.
The narrower the better.
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
_______________________________________________
PSDR mailing list
PSDR@hamwan.org
http://mail.hamwan.net/mailman/listinfo/psdr
PSDR mailing list
PSDR@hamwan.org
http://mail.hamwan.net/mailman/listinfo/psdr