[aprssig] E Coast 9600 baud backbone 15W radios.
Stephen H. Smith
wa8lmf2 at aol.com
Sun May 29 12:41:25 CDT 2016
On 5/29/2016 11:28 AM, Ev Tupis via aprssig wrote:
> From someone who has direct experience in this arena...the only reason is the cost of VHF SSB equipment.
> There is no issue with frequency stability as an SSB transceivers' passband is at least (grin) 2.5 kHz wide and decoder software can skim the entire waterfall looking for signals to decode. It is the premise of ACDS^31 software used by http://www.PropNET.org.
Actually, I was thinking of G4HYG's "APRS Messenger"
APRS-over-PSK63/GMSK250/PSK16 soundcard software which does NOT have any kind
of scanning or AFC-like action. It implements VERY narrow audio "slots" for the
incoming tones; i.e. less than 20 Hz. The program definitely depends on being
able to keep an SSB radio on-frequency to within 10-20 Hz RF indefinitely.
Something that is quite trivial at 10.1 MHz (30 meters) with modern synthesized
transceivers (My Kenwood TS-50 stays within 5 Hz indefinitely at 10.149 MHz
with a temperate indoor climate.), but a challenge with ham-grade radios at 144
(The latest version of APRS Messenger does offer an option of multiple pairs of
additional software modems at selectable intervals each side of the defined
center audio frequency. This comes at the expense of greatly increased CPU
Stephen H. Smith wa8lmf (at) aol.com
EchoLink: Node # 14400 [Think bottom of the 2-meter band]
Home Page: http://wa8lmf.net
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