• Effective immediately we will be deleting, without notice, any negative threads or posts that deal with the use of encryption and streaming of scanner audio.

    We've noticed a huge increase in rants and negative posts that revolve around agencies going to encryption due to the broadcasting of scanner audio on the internet. It's now worn out and continues to be the same recycled rants. These rants hijack the threads and derail the conversation. They no longer have a place anywhere on this forum other than in the designated threads in the Rants forum in the Tavern.

    If you violate these guidelines your post will be deleted without notice and an infraction will be issued. We are not against discussion of this issue. You just need to do it in the right place. For example:
    https://forums.radioreference.com/rants/224104-official-thread-live-audio-feeds-scanners-wait-encryption.html

255.550 FM - Spanish - 2:21 CST Up

Status
Not open for further replies.
Joined
May 10, 2005
Messages
0
Location
Euclid, Ohio
#2
I've been picking up some strong transmissions on this frequency as well, although it's a Eastern European language, not Spanish. Using my PRO-43 and Diamond RH-77CA.

Frank
Northeast Ohio
 
Joined
Jan 10, 2006
Messages
13
Location
Front Royal
#3
That frequency is used by Brazilian pirates and speaking Portuguese. They are on some others as well but 255.55 seems to be the one with the most traffic.
 

ryangassxx

Completely Banned for the Greater Good
Banned
Joined
Dec 26, 2006
Messages
309
Location
Inside of your head
#4
I was hearing it this morning... These guys hijack a military satellite to make these transmissions.. All it takes is a strong directional TX on the input freq of "296.550", and they can basically use one of the United States military satellites as their own private space repeater... Pretty crazy.. Speculation is that these are drug dealers discussing details for trafficking drugs..
 

KG9NZ

Member
Premium Subscriber
Joined
May 26, 2008
Messages
16
Location
Buffalo Area, NY
#5
How can these signals be so strong?

Satellite is presumably geosynchronous so it is going to be at least 36,000 km away even if it was right overhead.

Path loss (dB) is 32.5 + 20*log10(MHz) + 20*log10(km)
So in this case 32.5 + 20*log10(256) + 20*log10(36000)
= 172dB
Now I don't know what the ERP of the satellite is but lets take a guess and say its 10 watts on that particular frequency. Thats 40dBm. Therefore, received signal will be somewhere around -172 + 40 = -132dBm. Assume antenna has 3dB gain over isotropic. That's still -129dBm. That's 0.08uV. How many receivers have this kind of sensitivity? Yet I hear people describing receiving these with just the whip antenna on their receiver. I don't understand this. Certainly with a good gain antenna reception should not be a problem. But with just a whip antenna or even a discone? Unless my assumption of the satellite's ERP on that frequency is way low.

Frank KG9NZ
 

ryangassxx

Completely Banned for the Greater Good
Banned
Joined
Dec 26, 2006
Messages
309
Location
Inside of your head
#6
Satellite is presumably geosynchronous so it is going to be at least 36,000 km away even if it was right overhead.

Path loss (dB) is 32.5 + 20*log10(MHz) + 20*log10(km)
So in this case 32.5 + 20*log10(256) + 20*log10(36000)
= 172dB
Now I don't know what the ERP of the satellite is but lets take a guess and say its 10 watts on that particular frequency. Thats 40dBm. Therefore, received signal will be somewhere around -172 + 40 = -132dBm. Assume antenna has 3dB gain over isotropic. That's still -129dBm. That's 0.08uV. How many receivers have this kind of sensitivity? Yet I hear people describing receiving these with just the whip antenna on their receiver. I don't understand this. Certainly with a good gain antenna reception should not be a problem. But with just a whip antenna or even a discone? Unless my assumption of the satellite's ERP on that frequency is way low.

Frank KG9NZ

Well I can hear it really well with my MVT-7100, but with any of my other radios, nothing but static.. I think you do need to have a somewhat above average radio in terms of sensitivity..
 
Joined
Jun 30, 2006
Messages
7,514
Location
So Cal - Richardson, TX - Tewksbury, MA
#7
The older UHF transponders (Gapfiller) had an EIRP of around 23dBW and newer satellites are more. Even with some of the earliest UHF satellites, 23dBW and a 5dBi gain antenna on the ground would give around .45uv at the receiver assuming no other losses. I routinely pick up the newer satellites weakly with the stock rubber antenna on my PRO-43 and with a Maldol AL-500H they come in quite good.
I should post a pic of my UHF satcom mobile antenna, it brings in the pirates full quieting.
prcguy
Satellite is presumably geosynchronous so it is going to be at least 36,000 km away even if it was right overhead.

Path loss (dB) is 32.5 + 20*log10(MHz) + 20*log10(km)
So in this case 32.5 + 20*log10(256) + 20*log10(36000)
= 172dB
Now I don't know what the ERP of the satellite is but lets take a guess and say its 10 watts on that particular frequency. Thats 40dBm. Therefore, received signal will be somewhere around -172 + 40 = -132dBm. Assume antenna has 3dB gain over isotropic. That's still -129dBm. That's 0.08uV. How many receivers have this kind of sensitivity? Yet I hear people describing receiving these with just the whip antenna on their receiver. I don't understand this. Certainly with a good gain antenna reception should not be a problem. But with just a whip antenna or even a discone? Unless my assumption of the satellite's ERP on that frequency is way low.

Frank KG9NZ
 

chrismol1

Newbie
Premium Subscriber
Joined
Mar 15, 2008
Messages
22
Location
Saratoga
#10
Sure. I can hit the AO-51 amateur satellite with my 5 watt HT, no problem. Ain't no obstructions straight up into space!
yeh,

"i've heard that most of the signal goes into the sky"
Didnt really know if you could really hit a sat com with a regular HT and a "sticky duckie" antenna
All new thing now, wow
 

KG9NZ

Member
Premium Subscriber
Joined
May 26, 2008
Messages
16
Location
Buffalo Area, NY
#11
How are these people doing that?
Talking on satcoms?
with a 10 watt radio?
Most of the amateur satellites are much closer (say 1/10 of the distance) than the military satellites. That means their signal is going to be about 100 times as strong as the military satellites (if they are on the same frequency and running the same power). It's no problem to hear the amateur satellites, even with just a scanner. You can go to www.amsat.org and get a schedule of satellite passes based on your location. Pick a satellite that has FM voice, tune your scanner to the frequency at pass time, and you should hear them no problem. I had questioned how the military satellites which are so much further away could be heard. But someone explained that these have an effective radiated power of around 200 watts, which would explain why they appear so strong (the ham satellites and low orbit weather satellites usually run only a few watts). As far as reception in the other direction (military satellites receiving ground transmissions) that would be somewhat less impressive since I'm sure they have a receiver that is much more sensitive than the average scanner.

Frank
 
Joined
Jun 30, 2006
Messages
7,514
Location
So Cal - Richardson, TX - Tewksbury, MA
#12
The typical UHF satcom terminal is capable of 20 watts or so but you can communicate just fine down to about 5 watts with the most basic 5dBi gain antenna that folds up and fits in your shirt pocket. Some military users have had success communicating through the UHF satellites with the 5w MBITR or newer PRC-152 walki-talki.
prcguy
How are these people doing that?
Talking on satcoms?
with a 10 watt radio?
 
Joined
Jun 13, 2007
Messages
373
#13
How are these people doing that?
Talking on satcoms?
with a 10 watt radio?
they are most likely using 20watt Alinco DR-235 FM mobiles with the mod done to open up the transmit to 300mhz that can be found on the web.

that is why the 255.55 is the most herd freq. its input is the lowest and one of the few that is below 300 where it can be reached by the easily modded Alinco(available to anyone with $200 at your local HRO or AES).

there are pics at uhf-satcom.com of modded DR-235s in action on UFO satellites. there is even a pic of two alincos in the mod process.
 
Last edited:
C

comsec1

Guest
#15
elizibeth, nj busted

on 2/26/08 the fcc busted someone using 296.55 in elizibeth nj. call sign was n2kbj. probably a real good chance it was spanish from that area. check fcc web page for enforcment.
 
Joined
Oct 10, 2003
Messages
99
Location
Texas
#16
SatComm Comms.

Hello.

A LOT of 220 radios can do the military SatComs.
It is easy enough to where even I have done it.
It is the NTIA, and not the FCC, that gets to deal with you.
In my case I had IDed myself and said who I was and why I was doing it.
No biggie, and I wound up with some excellent contacts from within the military.
But, this was all done before 9/11, and things have changed.
 
Joined
Dec 19, 2002
Messages
881
Location
Houston, TX
#19
must have been the UHF FPP Satcom spectra.

i think the only contacts you would make as a result of bootlegging on the sats, would be to your arse in the pen.
 
Status
Not open for further replies.
Top