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

Wed May 28 20:25:53 PDT 2014

http://www.jarl.com/d-star/shogen.pdf Section 2.1.1

------------------------------
John D. Hays
K7VE
PO Box 1223, Edmonds, WA 98020-1223
<http://k7ve.org/blog>  <http://twitter.com/#!/john_hays>
<http://www.facebook.com/john.d.hays>

On Wed, May 28, 2014 at 5:12 PM, Bart Kus <me at bartk.us> wrote:

>  This is some really broad strokes.  Are there specifics on ID-1 protocol
> / framing somewhere?
>
> --Bart
>
>
>
> On 5/27/2014 4:59 PM, John D. Hays wrote:
>
> ID-1 simply encapsulates an Ethernet frame behind a D-STAR header.  The
> header has some correction, but the Ethernet frame is not corrected by
> D-STAR.
>
>
> ------------------------------
> John D. Hays
> K7VE
> PO Box 1223, Edmonds, WA 98020-1223
>  <http://k7ve.org/blog>  <http://twitter.com/#%21/john_hays> <http://www.facebook.com/john.d.hays>
>
>
> On Tue, May 27, 2014 at 4:28 PM, Bart Kus <me at bartk.us> wrote:
>
>>  There's no protocol I'm aware of that implements these features on top
>> of ID-1.  You'd need the ability to receive corrupt frames from the ID1 to
>> allow the use of FEC.  How does the ID1 handle corrupt frames?  Is there a
>> CRC or something in the framing?  For ARQ, you could keep the TX retrying
>> until it hears an ACK or times out.  Custom software would be needed, or
>> perhaps pppd can do such tricks, I dunno.
>>
>> Did you hear any signal when you listened with an FM receiver?  Can you
>> use an RTL-SDR or equivalent to see if there's any signal present?
>>
>> --Bart
>>
>>
>> On 5/24/2014 8:36 PM, Dean Gibson AE7Q wrote:
>>
>> That's what I figured ("features [that] are common to all WiFi systems");
>> it just made sense (although that is not always determinative!).
>>
>> So, my next question:  Is there an available tunneling protocol that
>> employs those features?
>>
>> Note that with the ID-1 in the *one watt* setting (same omni antenna), I
>> can use the 1.2GHz KB7CNN repeater 35 miles away on East Tiger mountain,
>> with no noise in the FM signal. The link to Paine (5 miles away) was tried
>> at max power (ten watts) on both radios.  I tried two different frequencies
>> (that's the beauty of being able to control both radios from one
>> location!): 1.250GHz and 1.249GHz (I listened on both in FM mode), with no
>> significant difference.  So, in my opinion, it's a path problem.
>>
>> On 2014-05-24 13:13, Bart Kus wrote:
>>
>> Wow that sucks.  :(  Is the signal level just too low?  Is it a matter of
>> interference?
>>
>> And yeah, I can confirm that the microwave stuff we use includes both FEC
>> (at up to 1/2 rate) and an ARQ system (look at "hw-retries" setting).
>> These features are common to all WiFi systems too, and they're just carried
>> over into our NV2 TDMA system.
>>
>> --Bart
>>
>> On 5/24/2014 10:19 AM, Dean Gibson AE7Q wrote:
>>
>> 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?"*
>>
>>
>>
>>
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