[ACARS] No Luck Here

[roger preston]

> Message: 8
> Date: Wed, 13 Mar 2002 22:11:55 +0800
> From: Subin Jacob <subs_sj@yahoo.co.uk>

> 
> I've been following all that has happening with PC-HFDL but
> today was the first day I actually got to try it out myself.
> Unfortunatly I don't seem to be getting any results :o(   I'm
> using a 1.7Ghz machine with a SB Live card, and for a long
> time VHF acars has been working very well with Wacars and
> 'Line In'. 
Set up sounds OK. I have a "Creative" sound card with a mixer program
that displays volume as a series of small bars horizontally. When the
radio is off, no green bars. With it on, the volume control on the mixer
screen is set to give all greens but no yellow/red. It's a direct output
on the HF225 radio so the signal can go into the mic socket on the sound
card. The program can cope quite well with adjusting sound level so if
you don't have a way of seeing the signal level, then try various volume
settings.
I've connected up my Sony 2001D with the audio coming from the green
socket (Tape recorder). There's just enough signal to drive the sound
card...
> But when I try HF monitoring with PC-HFDL I don't
> seem to be picking up anything.  I'm also using a Sony 2001D
> and have tried all the freqs in my region (Brisbane - ie.
> Guam, Auckland, Hawaii etc) but nothing displays on screen.
> Are you meant to get a squitter message every 32secs?  I can
> physically hear the squitters every now and again, but PC-HFDL
> only says "Listening" and that's it.  What could I be doing
> wrong here?  
What next. Can a Sony 2001D be used. Well yes as I've one doing it as I
write. Firstly, there'll need to be a strong enough signal - probably at
least two leds lit up but maybe it's Ok on one. I'm getting 5 or so from
the local station in Eire (I'm by LHR). 
Next, tuning. The Sony tunes in steps of 100 Hz. There will probably be
two freqs which will work as the Sony isn't likely to be dead accurate
on setting (mine has always been 200 Hz wrong meaning unless very hot
for 8942 kHz I need to set 8941.8KHz. That works fine and gives
-----------------
8941.7KHz - Preamble 300  bps 1.8 sec Interleaver FREQ ERR 52.244902 Hz
Errors 0
8941.8KHz - Preamble 300  bps 1.8 sec Interleaver FREQ ERR -46.466420 Hz
Errors 0 
---------------------
The freq errors shown above are low enough for the program to recover
the data as in 
-------------
Ground Station ID   = 7 SHANNON - IRELAND
----------------
08:40:54  UTC  Flight ID = LH8182  LAT 54 34 33  N  LON 55 55 39  W  
----------------
The DLH signal was a lot weaker but still decoded.

So what next. Listen to the signal (having set on SPDU, VERB and HFNPDU)
and when you hear the distinctive noise, tune the radio. If you are
listening to 8942KHZ USB aircraft transmissions, then the same freq
setting (+/- 100 Hz) should be correct for the ACARS signals. Now I
doubt you will get the Shannon signals where you live hence use the ones
you say you can hear. The display of just the squitters will appear in
the box where the text listening appears. Only when the tuning is
correct will anything appear in the lower larger window. Once you are in
business, you may want to switch off SPDU.

Hope that helps from one Sony 2001D user to another.


> Other thing I wanted to ask is, is it similar to wacars where
> the raw data is meant to be displayed on the top box, and any
> decoded data in the bottom box?  That is, every 32 seconds, is
> something new (whether it's actually decoded or not) should
> apprear in the top box?  I'm not getting anything?
What you see in the box depends on what is switched on (see above)

Regards
Roger