On 12/24/2024 2:41 AM, HB9BRJ via
groups.io wrote:
On Mon, Dec 23, 2024 at 07:29 PM, WA8LMF wrote:
WIDEn-N paths are NOT used on HF!??? I have seen
several new users running PinPoint without changing this
factory default.??
Sorry! Please provide path guidelines for APRS newbies like me.
Recommendations found online are highly inconsistent:
:
WIDE2-1
:
WIDE1-1
:
No path at all, or GATE, WIDE2-2.
Thank you!
?
73, Markus HB9BRJ
_._,_._,_
It constantly amazes me how the Internet
propagates incorrect and/or out-of-date infomation.....
The first two links above are from Australia, and for some reason
are blindly copying VHF/2-meters conventions, and suggest they be
used on HF.?? Since Australia is so far separated from the rest of
the world, radio-wise (and geographically) their non-standard path
conventions have almost no impact on the more populated parts of
the world.
The third one, from Indonesia, is a direct copy (without
attribution and minus the animated graphic), of my own web page?
at:
???? ??
Again, this applies to 2M/VHF -- not HF.??? HF practice is
discussed here on my web site:
???
Some basic? practices and thoughts about HF APRS operation.???
1)?? On VHF, radio transmission is primarily line-of-sight. Radio
coverage from a given location is a) relatively predictable and b)
easily blocked by objects (trees, buildings, hills). As a result,
digipeating (relaying transmissions using other stations) beyond
the line-of-sight makes sense.?
2)?? On HF, radio transmission primarily uses sky-wave
propagation -- the bending of radio waves far beyond the horizon
due to refraction in the atmosphere 100Km or more above the earth.
This refraction is due to the upper layers of the atmosphere (the
ionosphere) becoming electrically charged by radiation from the
sun.? This charging? effect constantly varies with time-of-day,
season-of-the-year and the roughly 11-year cycle of solar
activity.??Further, one-time events on the sun (solar flares,
coronal mass ejections -a.k.a. CMEs, etc) can disrupt the
ionosphere at any time.
As a result, radio propagation varies WILDLY from hour-to-hour
and day-to-day.? You simply CAN NOT expect a given other station
being available consistently to serve as a digipeater for your
station on HF.
3)??? Digipeating a transmission takes as much air time as the
original transmission.? One digi hop DOUBLES the air time. Two
digi hops TRIPLES the air time.? This drastically reduces the
capacity (messages-per-hour) possible on the shared channel.
4)??? On HF,? data rates are far far slower than on VHF/FM,?
further reducing the capacity of the shared single radio
channel.??
5)??? On VHF, digipeats occupy a geographic area of perhaps a
city-county-shire-province-canton-parish, allowing the same radio
channel to be used simultaneously in many places in the country at
the same time.???? On HF, your transmission (and it's digipeats)
may occupy a THIRD OF A CONTINENT or more at once, further
enormously reducing the capacity of the shared single radio
channel.
Path settings (WIDEn-N values) control the amount of digipeating
done. On VHF this works. On HF, digipeating SHOULD NOT be used!?
Most current APRS programs and APRS-enabled radios arrive
"out-of-the-box" with their digipeat paths defaulted to the
standard WIDE1-1,WIDE2-1,? suitable for two digi hops on VHF.?
When programs are used for HF operation, these hops should be
removed -- i.e. the path box should be left blank. ??
A) ?? Digi hops on HF are heavily discouraged
B) ?? The few digipeaters that do exist on HF DO NOT respond to
WIDEn-N paths -- They use "ECHO" instead.
C) ?? Adding the path values to your transmission only makes your
transmitted packet longer, taking up more air time and making it
less likely to be decoded successfully at the other end. ? ??
D)??? "GATE" as a path element is an anachronism from over 30
years ago,? that is needless today.
??? "GATE" in a path tells a handful of old hardware-based TNCs
(mainly Kantronics "KAM" dual-port) to cross-band digipeat from HF
to VHF. (You would have two radios, one HF and one 2M, attached to
ports on the same TNC.)
??? The hope was that then a local 2-meter station would hear you
and igate your transmission to the Internet. This dates from an
era, decades ago, when 24/7 always-on home internet connections
were uncommon (most people still had on-demand dial-up
connections) leading to few if any igates on HF.?? Again, due to
the unpredictable nature of HF propagation, you never knew what
geographic area(s) you would be GATED to on VHF.?
Today, there are numerous igates directly receiving off HF -- the
"GATE" clause in a path just makes the transmission needlessly
longer.
??? Once again, FOR HF, the path settings
should be blank.
P.S.? I invented the double WIDEn-N construct for APRS paths on
VHF over 30 years ago, ? to solve digipeating problems with
brain-dead Kantronics KPC-3 TNCs that were widely used as
digipeaters at the time.
Stephen H. Smith??? wa8lmf (at) aol.com
Skype:??????? WA8LMF
EchoLink:? Node #? 14400? [Think bottom of the 2-meter band]
Home Page:?????????
30 Meter?? APRS-over VARA? Frequency Change
Coming 1 Jan 2025.?? Details Here:
????
- APRS over VARA? --
??
"Studio B" Ham Shack on Wheels
??
-
?
Rick - KJ7ROX
