Order Tray | Contact Us | Home | SIG Lists

[aprssig] APRS low-power-local ALT input channel

Robert Bruninga bruninga at usna.edu
Fri Sep 24 16:17:11 UTC 2004


Establishing a local ALT input for APRS in USA:

With the proliferation of low power tracking devices and 
HTstyle APRS operations (see Pocket Tracekr in Oct QST), 
we must seriously look at the option of adding (in congested 
areas) an alternate input channel for APRS. 

There would be NO digi *tansmitters* on this freqeuency, only 
receivers, and a few low power trackers and a few other 
APRS stations maybe beaconing once every 30 minutes 
or so.    Packets HEARD on this channel are not digipeated 
there, but are digipeated over to 144.39 where EVERYONE 
listens.  In fact, due to the low duty cycle and low power 
and NO high transmitters, this channel CAN be shared with
other agreeable users of BBS's, Nodes and DX clusters...
Who would have priority if for no other reason than the
fact that they are typically using 20 dB more power and will
capture everytime...

144.99 MHz is ideal for this application if it is avaiable 
in your area becasue it is +600 from 144.39 MHz.

I just Googled 144.99 MHz and looked at the top
120 hits (12 pages) and the channel is coordinated
for packet everywhere.   But only a few areas have
BBS's or NODES or DX clusters there.  (see list below).

This is *not* bad news, but almost good news.  This
means that in some areas, there are already HIGH
sites *listening* on 144.99 with SITES, Antennas and
RECEIVERS.  All you have to do is pull any APRS
packets heard and send them over to 144.39.  Done...

And of course work well with those existing users.  We do
not intend to usurp the frequency.  But in all areas, the
Node packet traffic has dropped by an order of magnitude
since the mid 1990's where these systems first went up.
Maybe many of any existing users of those channels may
also be in APRS now.  The idea is to work with packet
radio in your area, and see if some low power trackers
can be permitted to operate on 144.99 in your area.
Certainly these under-1-watt occassional packets cannot
really interfere with 50W base stations who are the typical
users of these BBS's and NODES.

Please take a look in your area.  Another good advantage of
144.99 was that it WAS reserved for SAREX voice uplink
during the early 1990's  before the big move to the new
ARISS frequencies.  Thus, unless a DX cluster moved in,
these frequencies were not used for packet during the
peak in packet activity and may still be available in your area.
Please check with your coordinateors!

We are using 144.99 in Annapolis MD as an alternate input
and it works great for local trackers and fixed stations...

If you see the potential for this growth, I ask you to also GOOGLE
for 144.99 MHz *and* your STATE.  Do a thorough search for
any other use or coordination in your area and lets get
this ball rolling...  talk to people cooperate, lets see what we
can do...  Here are the first 120 hits I found without being
specific by state:

Google hits on "144.99 MHz":

AZ: Prescott Vy
CA: Berkely, Benicia, NoCal,, LA, Stockton
FL: Augustine, Gainsville
KY:  Bowling Green
NH: Hannover
NY: Jamesport
OR: south, HCKNSN, Eugene
PA:  Abington
WA: Bremerton, Vancouver
WI:  Ozaukee Co

Please do a more thorough seach in your area.  thanks
After you find that it is acceptible use for an APRS
alternate low power input channel, then let us know
so we can get the word out...

Bob, WB4APR




More information about the aprssig mailing list