[aprssig] APRS on HF

Ramakrishnan K.A. vu2kuc2 at gmail.com
Sun Feb 20 07:51:33 EST 2011

To get start of  APRS on HF what are basic requirements can anyone guide me

other than HF equipment and antina.


On 2/20/11, Stephen H. Smith <wa8lmf2 at aol.com> wrote:
> On 2/20/2011 12:50 AM, Julian, G4ILO wrote:
>> Having run a 30m IGate (G4ILO-1) for several months now I have often
>> been the station that gates European HF mobiles to APRS-IS. I
>> understand that in areas where there is little VHF coverage (which
>> includes much of the UK) a mobile has a better chance of being gated
>> if they use HF, even though they will be gated by someone 1,000 miles
>> away. So is that the only real purpose of APRS on HF, to gate HF
>> mobiles? And if so, why do HF IGates need to transmit?
>> Julian, G4ILO
>> G4ILO's Shack: www.g4ilo.com
> Support of mobiles in remote locations has been the main use of HF APRS in
> North America.
> In the American west (and all of Canada more than 100 miles/160KM north of
> the
> US border), the population density is EXTREMELY LOW and VHF infrastructure
> very
> sparse.    In the US alone, this is an area approximately ONE THOUSAND MILES
> SQUARE (1600 KM square) in the western one-third of the country.    (Once
> you
> go more than about 100 miles east in from the Pacific coast, coverage
> shrinks
> to almost nothing, except along the major Interstate highways and islands of
> coverage in cities that are hundreds of miles apart.)
> Turn off the Interstates onto the secondary roads and scenic byways in the
> west, especially in mountainous terrain, and you drive off the edge of the
> world APRS-wise on VHF.     HF coverage covers this mountainous Great Basin
> area (the interior west between the Sierra Nevadas in California and the
> Rocky
> Mountains of Colorado) very well.    Depending on the time of day, you are
> either propagating eastward to igates in the MidWest and/or the East Coast,
> or
> westwards to igates on the populous Pacific Coast, or both.
> HF APRS is also widely used by pleasure boats in the Caribbean, and off the
> west coast of the US and Mexico, once you get more than about 30 miles from
> shore.   Given the very limited capacity of a 300 baud (or slower) channel,
> and
> the fact that every transmission occupies the channel for a radius of
> 500-2000
> miles, depending on propagation,    absolutely the last thing thing you want
> to
> do is gate VHF traffic onto HF.
> About twice a year I drive from Los Angeles, CA to East Lansing, MIchigan
> (my
> home town where my sister and mother still live) --- a trip of about 2200
> miles/3500 KM each way. For about 600 miles of this trip there is just NO
> coverage at all.
> One-way igates break a major feature of  APRS operation:  two-way messaging.
> I have carried on extensive two-way messaging from my mobile with the HF
> Messenger application on the last three or four cross-country trips.   Most
> contacts have been RF<-->RF, but I have had exchanges with a station in Los
> Angeles coming out of an igate on the East Coast while I was mobile in the
> southern Utah desert -- an RF haul of over 2000 miles.        The
> effectiveness
> of PSK63 over weak signal paths is dramatic when working from a mobile in
> the
> boondocks of the Great Basin.
> -------------------------------------------------------------------------------
> --
> Stephen H. Smith    wa8lmf (at) aol.com
> EchoLink Node:      WA8LMF  or 14400    [Think bottom of the 2M band]
> Skype:        WA8LMF
> Home Page:          http://wa8lmf.net
> =====  Vista & Win7 Install Issues for UI-View and Precision Mapping =====
>      http://wa8lmf.net/aprs/UIview_Notes.htm#VistaWin7
> *** HF APRS over PSK63 ***
>     http://wa8lmf.net/APRS_PSK63/index.htm
> "APRS 101"  Explanation of APRS Path Selection & Digipeating
>    http://wa8lmf.net/DigiPaths
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