[ACARS] ACARS Receiving

Sun, 25 May 2003 09:05:56 -0500

Hi Carlos:

I have experienced similar fluctuations here in Chicago as well. My log
sizes are typically 6-7meg but sometimes go as high as 10meg and as low =
as
3meg. A couple of things factor into this:

1/ Winter time typically sees better VHF propogation.=20

2/ When the decreases happen, they usually come back to normal reception
within a day or two.=20

3/ I too scan 24 hours a day but it is often a good idea to re-boot the =
PC
every couple of days asmany computers suffer from memory leaks that are
corrected during a re-boot.=20

4/ As the reception of ACARS goes up and down with propogation changes, =
so
will interference. Living near an interstate I get occasional crosstalk =
from
the truckers frequencies as well as a radio repeater located about 1.5 =
miles
away. That is often hard to detect but will definitely be more of a =
problem
if you use a gain amplifier.=20

5/ Generally speaking the high pressure and dry air periods of spring =
and
fall are when these drop offs occur the most.=20

Hope this helps.

Steve

-----Original Message-----
From: [email protected] [mailto:[email protected]] =
On
Behalf Of Carlos Abreu
Sent: Friday, May 23, 2003 4:57 AM
To: [email protected]
Subject: [ACARS] ACARS Receiving

Hi List

Could anyone help me with the following problem (?):

Since a 1999 I monitorize ACARS 24H per day, I live less than 10 miles =
from
Lisbon International Airport (Portela LPPT/LIS), normaly I pick up =
around
2000 messages (and sometimes 3000 & more) using a Notebook Toshiba =
Satellite
4070 CDT connected to a Radio Shack PRO-29 scanner, a Watson WRP-125
amplifier, a AOR ABF 125 filter for airband and a Radio Shack internal
antenna with 9 extended sections.

However during some days with excepcional summer weather like today with
clean sky, a very high temperature and no humidity my receiving messages
decrease for only an hundred or a little more than that...
All uplinks are missing (?) I jus pick up some downlinks (?).

It is a rare situation but isn't the first time it happens, I lived in a =
5th
floor that in a high place that is good for reception signal, from my =
large
window I can see all final approach to runaway 03 from LPPT, as a =
ex-SITA
staff I called my friends from OPR dept and they confirmed to me that no
maintenance was made in Aircom antenna in the airport and the system was
working fine, I checked the equipment and it's everything ok, no wires =
were
moved, the apartment is climatizated what means no problems with =
equipment
performance, there=B4s any physical external interference...I can't =
undersatnd
this !!!

Can any list member give an opinion about this or shared any knowledge =
about
this strange phenomenon.

Many thanks in advance and best regards.
Carlos

_____________________________________________
Acars info and Aircraft ID answers go to: http://www.acarsonline.co.uk =20
[email protected]
http://mailman.qth.net/mailman/listinfo/acars