[HamWAN PSDR] 1.2GHz to Paine [was: 44.x.x.x HamWAN network at Paine]

[Bob]

Dean,

Here are some observations and conclusion that I have come up with in adding
the ID-1 to the Kirkland Emergency Communications Team's tool box.  I have
done a number of tests of the ID-1 from various locations in Kirkland in
both the Digital Data (DD) mode and the Digital Voice (DV) mode.  I tested
simplex paths (ID-1 to ID-1) and paths to the Lake Washington Ham Club
(LWHC) DSTAR DV repeater and DD gateway nodes in Bellevue.

 

1.      There are a few locations in Kirkland that have direct visual line
of site to LWHC Gateway in Belleview.  From those locations, pings are
consistently returned in 100 to 200ms with an occasional loss.

2.      We have two location (Stations 22 and 25) are not visual but
according to Radio Mobile modeling skim the terrain.  At these sights no
ping are returned.

3.      At my home QTH (Lat: 47.694 Lon: -122.2161) I do not have a visual
of the LWHC Gateway, but I get occasional pings returned.

4.      John Hays loan me a 1.23 GHz directional antenna. With the
directional antenna I detected two paths to the gateway.  One was off a
condo about 180 degrees from the gateway about a mile away; the other was
off the NOAA building four miles awat at Sand Point about 15 degrees
clockwise from the gateway.  This indicates the presents of multi-paths that
could be interfering with the data even with good signal strength.

5.      I will also confirm the DV mode is more robust than the DD mode, but
it too is affect by multi-path.

 

About 2 weeks ago I brought the ID-1 on line to serve as an alternate path
to the Winlink CMS.

 

Bob - KE7JL

 

 

 

From: PSDR [mailto:psdr-bounces at hamwan.org] On Behalf Of Dean Gibson AE7Q
Sent: Saturday, May 24, 2014 10:20 AM
To: Puget Sound Data Ring
Subject: [HamWAN PSDR] 1.2GHz to Paine [was: 44.x.x.x HamWAN network at
Paine]

 

Scott Honaker and I have moved forward on this project:

1.	We have installed a gateway (Linksys BEFSR41) between the ID-1 and
the internal ARES/RACES subnet (not 44.x.x.x) of the DEM.
2.	We have installed a Digi "AnywhereUSB" box to give us remote access
to the ID-1's USB port, and thus remote control of the ID-1 radio.  This not
only allows multiple use of the ID-1 (which has useful 1.2GHz FM and digital
voice modes as well as Ethernet data), but provides for remote frequency
agility and a diagnostic capability.  This works beautifully (eg, to search
for and use a low-noise frequency)!

Unfortunately, what does not work very well, is the RF portion of the
connection.  PINGs failed at a rate of over 99% when using the 1.2GHz
antenna at the 70 ft level on the tower, so we swapped the antenna with the
one used for the Icom 1.2GHz repeater (which wasn't seeing any action
anyway) at 100 ft.  That made a "dramatic" improvement, as PINGs now only
fail at a 98% rate (depends upon the time of day, etc)!

Antenna comparison between 1.2GHz and 5.9 GHz for the two sites:

1.	On 1.2GHz, both antennas are omni-directional.
2.	At the DEM, the 1.2GHz antenna is now at the 100' level, whereas the
5.9GHz antenna is at 150'.
3.	At my home, the 1.2GHz antenna is about 10' above the 5.9GHz
antenna, and it's on the same line-of-sight path.

Note that voice communication between the two sites using the two ID-1
radios, is fine (there is a slight bit of noise on FM).

The big difference, in my opinion?  I'll bet that the wireless protocol used
by the MikroTik radios includes an aggressive error correction and retry
protocol, whereas the ID-1 is like a piece of Ethernet cable, and thus
relies on the standard TCP/IP retry mechanism.  The TCP/IP protocols, while
"unreliable" in the technical sense of the term, require a higher overall
reliability than a typical raw wireless connection.

What this says (and I'm a bit surprised to note this), is that sites
considering using ID-1 radios for data communications, may find that even
with the tighter siting requirements of 5.9GHz, that the latter may be more
successful (whether or not part of HamWAN).  In addition to being a
lower-cost radio with a much higher data rate, the MikroTik radios offer a
built-in router, which can obviate the need for a separate router.

-- Dean

ps: The callsign and digital code filtering features of D-Star that we
previously discussed, are not available (greyed out in the software) for
digital data mode.  Huh?  Another fine example of software of the "seven
last words" of poor program design: "Why would you want to do that?"

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.hamwan.net/pipermail/psdr/attachments/20140524/b99b7039/attachment.html>