[HamWAN PSDR] Beacon Tower-Capital Park Backbone Link

Randy Neals randy at neals.ca
Wed Mar 28 13:41:26 PDT 2018

Thanks for the response Tom,

The link between Queen Anne and Capital Park looked like a client radio
connecting to sector, so I didn't count that.
>From your description, it sounds like a proper PtP back of some sort - yet
the Queen Anne site isn't exactly a full HamWan node, so not sure how that

Other bands I considered are 2.4 GHz, 3.4 GHz and 10 GHz.

*10 GHz* is an ideal band for these links.
However, the only commercial radio that will work on the 10 GHz ham band is
the Mimosa B11.
Yet, the 10GHz mimosa stuff is $2,000 an end. Pricey.
The amateur community would prefer to not support mimosa - And I understand
that. The practicality is that any volume of radios that Amateurs would buy
from Mimosa won't make or break the company.
In refusing to use Mimosa, and in not having other equipment choices for 10
GHz, we are actually making Mimosa's statement true that the 10GHz band is
not well utilized.
Deploying a few 10GHz links would make the band harder to take away. A
physical act of spectrum defence.

*3.3 to 3.5 GHz* is a ham band.
Ubiquiti Rocket M3's (International) work on 3400-3500 MHZ, although the
new Citizens Broadband Radio Service just took away 3450-3500 from the
Amateur band.
3400-3450 is still available for our use and works on UBNT.

Ubiquiti has a 3 GHz radio card, the XR3.
I think that is compatible with Mikrotik Routerboard - so in theory an XR3
and Routerboard would still run Router OS.
Frequency selection on the XR3 is done by configuring the RouterOS as
though it is a 5 GHz radio.
But I think that is also limited to 3400-3450.

Cambium has 3.3 to 3.8 GHz radios, but I'm not familiar with the product
and it's more expensive than Mimosa.

On *24 GHz*, the other equipment option in UBNT airfiber.
Quite a bit more expensive than Mimosa's new product, but I think also
higher power.
Maybe the Mimosa price pressure will cause UBNT to lower the cost of their
24 ghz product?

Because this is an ISM / unlicensed band, I think we'll see more equipment
choices in 24ghz, but its really so distance limited that the number of use
cases where Hams can use 24Ghz is tiny.

The 500 MHz of spectrum in the 10 GHZ band has such great potential for
backbone links between sites.
I wish more of the 11 GHz commercial WISP PtP system would work in the
10GHz ham band.

The continuing push by the FCC to make vendors software-lock frequency
ranges on commercial radio systems is actually hampering our traditional
amateur mode of using surplus commercial radio gear.
Bands like 2M and 70cm owe their popularity today to a long history of
surplus commercial radio equipment flowing to the ham community for a
second life.


On Wed, Mar 28, 2018 at 8:46 AM, Tom Hayward <tom at tomh.us> wrote:

> Randy,
> Capitol Park also links to Queen Anne, which links to Haystack, so it's
> not single-homed. That said, there's a lot that could be improved at
> Capitol Park. It has traditionally been hard to get access to, so it
> doesn't get much love.
> We've never done any 24 GHz, and $1458 is a lot to spend on one link.
> We've also never done any non-Mikrotik gear. A consistent OS makes writing
> configuration automation a lot easier. Change is hard.
> I agree with Bryan's point that I don't want to support a company lobbying
> to take 10 GHz away from hams. I took a quick look and other 24 GHz gear
> appears to be about twice as expensive. Hmm.
> There's a lot of broken stuff right now, so my priorities for the next few
> months will be helping with repairs rather than improvements. And East
> Tiger is now single-homed, so it would be nice to find something for it to
> connect to in the SW direction.
> Sorry for the lack of depth. Busy week.
> Tom
> On Wed, Mar 28, 2018 at 1:41 AM, Randy Neals <randy at neals.ca> wrote:
>> Hi,
>> I was digging through the HamWAN Map and Monitoring site to better
>> understand the connectivity and redundancy of the backbone supporting the
>> two key Seattle HamWAN sites, Beacon Tower and Capital Park.
>> To recap what I observed...
>> Documentation suggests *backbone connectivity at Capital Park* is:
>> a. PtP link to Baldi
>> b. PtP link to Paine
>> The Capital Park to Baldi PtP actually appears to be a
>> Point-to-Multipoint Link with 2 clients registered on the Baldi radio. I
>> suspect that is Capital Park and Beacon Tower sharing access to a single
>> dish/radio at Baldi.
>> The Capital Park to Paine PtP seems to be decommissioned.
>> *Question:* Am I correct in believing that Capital Park is
>> single-threaded with just one backbone connection to Baldi operational?
>> *Suggestion:*
>> I think it might be prudent to have a direct PtP link between Capital
>> Park and Beacon Tower.
>> The sites are 4km apart with good visual line of sight. These two sites
>> are very important to Seattle users.
>> *Proposal:*
>> 24 GHz is both an Amateur Radio band, and an ISM unlicensed band.
>> This band works very well on short point to point paths. Further, 24.05
>> to 24.25 is an ISM band and can carry commercial traffic or amateur traffic.
>> 24 GHz could be utilized on the Beacon Tower to Seattle EOC link.
>> This link is very short (1.1 Miles/1.7 Km) and is a really good use case
>> for 24 GHz.
>> Equipment for 24Ghz is not particularly expensive.
>> Mimosa announced a new B24 model on March 6 that has a $729 per end cost
>> for integrated dish/radio. https://mimosa.co/products/specs/b24
>> Using 24 GHz to the EOC would allow the repurposing of the 5GHz link
>> intended as Beacon-EOC to be a new backbone path Beacon Tower to Capital
>> Park. I believe there is ample room at Capital Park to add a 2' dish
>> pointing at Beacon. This path is about 4km and would not be suitable for 24
>> Ghz.
>> The outcome of this proposal would be:
>> 1. Seattle EOC-Beacon being linked at very high speed over 24 GHz. (circa
>> 1 Gb/s)
>> 2. Beacon Tower-Capital Park also having a high speed 5GHz backbone
>> (circa 100 Mb/s)
>> These key sites in Seattle would be less reliant on Gold, Baldi, and
>> Haystack for connectivity within the City of Seattle/across town.
>> There is an obvious cost implication for this change, but it's not
>> particularly large and could make the network more robust. I'd be willing
>> to contribute to this and others may also also do the same.
>> Thanks for reading this and considering it.
>> Randy
>> W3RWN
>> _______________________________________________
>> PSDR mailing list
>> PSDR at hamwan.org
>> http://mail.hamwan.net/mailman/listinfo/psdr
> _______________________________________________
> PSDR mailing list
> PSDR at hamwan.org
> http://mail.hamwan.net/mailman/listinfo/psdr
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.hamwan.net/pipermail/psdr/attachments/20180328/5d9c2c87/attachment.html>

More information about the PSDR mailing list