Stepsize and bandwidth SATCOM

Status
Not open for further replies.

Saint

Member
Premium Subscriber
Joined
Dec 19, 2002
Messages
4,855
Location
Fort Erie Ontario Canada
I want to search between 240,000 and 270.000 MHz for pirates and others, I am running SDR# 1919 Studio software. Is this the way to setup to scan the frequencies.
NFM
StepSize=12.000
BandWidth=25.000
or is this wrong, I am using my Discone antenna, I do have a longwire outside also, any pointers would be helpful.
Steve
 

Saint

Member
Premium Subscriber
Joined
Dec 19, 2002
Messages
4,855
Location
Fort Erie Ontario Canada
I would search 243.5 to 270MHz, 25KHz step size and 15 to 25KHz BW is good. You might tilt your Discone mast to the North so it has a better radiation pattern upwards and to the south.
Thanks so much for the info, I changed my settings to 25-bandwidth and 25 step, I'll see if I pickup anything, I have my discone on my fourth floor balcony facing north.
Steve
 

prcguy

Member
Premium Subscriber
Joined
Jun 30, 2006
Messages
16,444
Location
So Cal - Richardson, TX - Tewksbury, MA
Thanks so much for the info, I changed my settings to 25-bandwidth and 25 step, I'll see if I pickup anything, I have my discone on my fourth floor balcony facing north.
Steve
From your location the satellite arc will start from the south east at the horizon to due south up about 30deg elevation then back down to south west at the horizon. You will need an unobstructed view of all that. A balcony facing north with a building in the way to the south will probably not work.
 

Saint

Member
Premium Subscriber
Joined
Dec 19, 2002
Messages
4,855
Location
Fort Erie Ontario Canada
From your location the satellite arc will start from the south east at the horizon to due south up about 30deg elevation then back down to south west at the horizon. You will need an unobstructed view of all that. A balcony facing north with a building in the way to the south will probably not work.
some tops of trees are in my way but no buildings, when I go out on my balcony I see north, east, west, When I first started to scan the frequencies I did pickup a voice, but I did not move fast enough to see what frequency it was, it only lasted for a few seconds and never found it again. Than was about an hour ago, 9 - PM 21:00 UTC
Steve
 

mancow

Member
Database Admin
Joined
Feb 19, 2003
Messages
6,905
Location
N.E. Kansas
Just be aware most of the pirates seem to use a 10 or 20 k step so they often end up a bit off centered in the transponder.
 

mancow

Member
Database Admin
Joined
Feb 19, 2003
Messages
6,905
Location
N.E. Kansas
No, stay with the 25. I'm just saying it's something to be aware of if seems you can't quite tune them in.
 

dlwtrunked

Member
Premium Subscriber
Joined
Dec 19, 2002
Messages
2,381
Just be aware most of the pirates seem to use a 10 or 20 k step so they often end up a bit off centered in the transponder.

You beat me to saying the same thing. But if you go by the 25 kHz steeping, using search mode does not really make since as the channels of the "bent pipeline" down link are generally known and scanning them will be faster than using search mode.
(I need really no say I hope, that using an SDR and waterfall display is really, by far, the best way to look for this activity. You can see the channels with noise in the always on downlink and at the same time tell when an FM signal takes over that channel.)
 

prcguy

Member
Premium Subscriber
Joined
Jun 30, 2006
Messages
16,444
Location
So Cal - Richardson, TX - Tewksbury, MA
some tops of trees are in my way but no buildings, when I go out on my balcony I see north, east, west, When I first started to scan the frequencies I did pickup a voice, but I did not move fast enough to see what frequency it was, it only lasted for a few seconds and never found it again. Than was about an hour ago, 9 - PM 21:00 UTC
Steve
Your Discone needs to see east to south to west. A Discone can pick up some UHF satcom but you will need an antenna that has more gain and/or right hand circular polarity to work the best.
 

Saint

Member
Premium Subscriber
Joined
Dec 19, 2002
Messages
4,855
Location
Fort Erie Ontario Canada
Your Discone needs to see east to south to west. A Discone can pick up some UHF satcom but you will need an antenna that has more gain and/or right hand circular polarity to work the best.
Yea I thought the discone was pointing the wrong way I have the same problem with trying to pick up the satellites in the HF bands also, This is a video of what I am seeing on the waterfall.
Steve
 

mancow

Member
Database Admin
Joined
Feb 19, 2003
Messages
6,905
Location
N.E. Kansas
The newer UHF Follow On satellites are pretty hot and can be picked up on Discones and handhelds depending on look angle. Some of the older sats need a lot more antenna to get a useable signal.
Pimp him your homemade antenna plans. It works well.
 

Saint

Member
Premium Subscriber
Joined
Dec 19, 2002
Messages
4,855
Location
Fort Erie Ontario Canada
Yea on HF, when trying to pick up the marine and aircraft, I had to put the little antenna I bought on a long stick and take the screen of my window that faces SOUTH to pickup anything. But that's not practical it lets bugs into the apartment, also a little cold in the winter time so I gave up on listening to these satellites . I did pick up a little audio on the 240-270 MHZ band for a few seconds but it was in scan mode and I never found anything again.
Steve
 

Saint

Member
Premium Subscriber
Joined
Dec 19, 2002
Messages
4,855
Location
Fort Erie Ontario Canada
Well you aren't missing anything. It's just static and morons speaking Portuguese.
Kind of thought it was like cb radio, it was a lot of fun in the 70's but it turned into a three ring circus with too many clowns out there.
Any way there is a lot of other things to listen too. Thanks everyone for all the help in answering my question.
Steve
 
Status
Not open for further replies.
Top