[amsat-bb] Falconsat-3 - The APRS satellite for Mobiles

[Jim White]

One other note,  the FS3 receiver is very sensitive.  In the absence of 
interference it can make bits from an uplink of about 5W into a whip.  
As a further comparison, just after launch when we tested the FM 
repeater (sadly no longer working), we talked 3W HT to HT with 1/4 wave 
whips across a parking lot using FM voice full quieting. It still hears 
just as well thanks to the excellent SpaceQuest radio hardware.

So 15W or so to a mobile whip should be more than enough under nearly 
all circumstances.

Jim

On 2/20/2019 12:06 PM, Robert Bruninga wrote:
> Work a satellite from your APRS mobile, 5 times a day:
>
>
>
> For APRS folks just sittin in their mobile with nothing to do, you can work
> FALCONSAT from any APRS Mobile…  Just confirm passes using Heavens-above.com
> (be sure to enter your location).  Though passes now are from about
> midnight to 6 AM, that pattern moves earlier about 36 minutes a day so it
> will be in the evenings in a few days.
>
>
>
> The Falconsat digipeater operates APRS at 9600 baud and works fine from a
> 50W APRS mobile with mobile antenna.  Just turn on your rig, set the
> internal TNC to 9600 baud and monitor the downlink.  You should see packets
> from PFS3-1 and or other stations.
>
>
>
> Tune 435.110 MHz at start of pass, then clicking down steps of 5 Khz
> towards the middle of the pass and then ending at 435.095 by the end ten
> minutes later.  If you are just going to monitor overnight, set to 435.105
> for the early middle of the pass and check your LIST in the morning.
>
>
>
> Uplink takes a bit more settings.  Set your PATH to go via PFS3-1 and set
> TNC to TX A and  RX B and set uplink on band A to 145.84 (no need to step
> doppler).  Set beacon to once a minute (and turn off decay and
> Proportioinal pathing).  You will NOT see your own digipeats.  Although the
> satellite and D710 are operating full duplex, the D710 TNC is not.  By the
> time the TNC TX/RX turns around, you will already have missed it.  So don’t
> just keep TXing until success,  You WONT see it.  But when you DO see
> someone else doing APRS, then by all means send them a message.  If he
> ACKS, then success!
>
>
>
> I just did the math.  You don’t even need no stinkin computer.  Once  you
> hear a pass, then just remember that passes are 36 minutes earlier each day
> and the next pass on any given day is 98 minutes later (unless that was the
> last pass of the day).  During a western trip, just jotting down the time
> of a pass heard, then I could predict pass times therest of the day and
> every day for weeks.  Always just adding 98 minuets to the next pass and
> listening 36 minutes earlier each day.  See this manual technique:
> http://aprs.org/MobileLEOtracking.html
>
>
>
> Here is how WD9EWK describes working FALCONSAT:
>
> https://www.amsat.org/wordpress/wp-content/uploads/2018/03/FalconSAT-Stoddard-pdf.pdf
>
>
>
> Anyway, it’s a great satellite while mobile that needs no special
> antennas.  Just keep up with when it is generally coming over and have the
> frequencies already programmed into a channel in your radio.  Actually,
> program four frequencies to make it easy to shift for doppler.
>
>
>
> We will try to remind everyone when passes enter more favorable evening or
> morning commute hours…
>
>
>
> And here is a note I got form himpatrick at wd9ewk.net today:
>
> Bob, WB4APR
>
>
>
> *From:* Patrick STODDARD wd9ewk
> *Subject:* Re: [amsat-bb] D72 to Falconsat-3 APRS
>
>
>
> FalconSAT-3 uplink sensitivity is good. I regularly work it
>
> with 5W from my TH-D72 with a handheld beam… I have used a TM-D710G at its
> various power levels, and 5W from the mobile radio works fine.
>
>
>
> Downlink power... it is strong. I can hear it a few degrees
>
> above the horizon.
>
>
>
> I have used a TH-D72, TM-D710G, a pair of TH-D74s (The TH-D74 cannot
> operate APRS crossband)
>
>
>
> I wrote about using these different radios, and combinations
>
> of radios, for the AMSAT Journal in late 2017:
>
>
>
> https://www.amsat.org/wordpress/wp-content/uploads/2018/03/FalconSAT-Stoddard-pdf.pdf
>
>
>
> 73!
>
> Patrick
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