QRM on packet frequency
Did anyone else here the interference on the 145.825MHz packet frequency today. It sounds like some digital noise repeating over and over. It is not as strong as a packet burst from the ISS but it is enough to hold the squelch open unless you advance it quite a bit. The strength of the interference seems to come up with the elevation of the ISS and it goes away as the satellite gets to the horizon so I assume it is coming from the ISS itself.
Julian, G4ILO
g4ilo – Wed, 2010 – 09 – 22 07:39
QRM
Today had QRM on 145.825 from another satellite.I used Orbitron to check other passes.
I come across UO-11 that was over east coast.I also checked AMSAT web site and found
the downlink frequency is 145.826!
QRM
Apparently, OSCAR 11 beacon on 145.826 has been active sporadically for the last several years. The satellite's batteries don't charge anymore (its over 25 years old!), but the TM beacon can be heard at times when it is in the sun. It seems that it's been pretty active lately.
QRM On packet Frequency
I agree, I also heard the signal, albeit weak, on 145.825 during their 0950UTC pass. Although the signal was very noisy, it sounds to me like someone is beaconing their data in 5 second intervals or so. My receiver was not able to decode it as it was too weak, but maybe someone else in the group will be able to pick it up and find out who it is.
It sure makes it hard for the rest of us to get in when someone does this.
BTW - Aren't they (ISS) supposed to be on 145.800 over Europe??
Floyd DA1VF/WD8DUP
QRM on Packet Frequency
I should mention that I am located in Stuttgart, Germany and the signal "may" be from the ISS itself, like it's picking up something in the background or crosstalk.
SRI about the frequency but it is 145.825/worldwide. 145.800 is voice/Worldwide .....
Floyd DA1VF/WD8DUP
Time for another pass in 5 minutes (for me anyway)....
QRM on Packet Frequency
Hmmmm, we may have caught on to something here, but it'll take a better antenna with better gain to figure it out.
According to AMSAT and the Navy web site, the CASTOR satellite is still operational, although AMSAT says its status is unknown. It operates on a 145.825 AX.25 1200 downlink. Since it was lauched in 2006 by the shuttle, I'm wondering if this is what we've been hearing.
Also according to AMSAT, there are only a handful of sats that even work on or near that frequency as a downlink. I haven't had the chance to "back track" any of these to see what the possibilities are we may be hearing a sat that either "tags" along with the ISS or just happens to be in its general vicinity recently. In any event, it will eventually move on and we'll have undisturbed (more or less) comms again.
Floyd DA1VF/WD8DUP
QRM on Packet Frequency
This is an interesting topic that is developing. For two nights in a row I've heard the beacon from UOSAT 2 (I believe a.k.a. Oscar 11) on 145.825 (Uploaded an audio of it today, 9/24/10 ~ 04:15 UT). Sounds like a cornucopia of floating sources up there all bunched up on that same freq!!! 73
QRM on Packet Frequency
Was monitoring 145.825 for the beacon from one of the Oscars on the night of Sept 20 (~ 04:00 UTC Sept 21) and QRM was so intense I had to turn up squelch almost all the way to cancel. No QRM a few KHz off from that freq. QTH in California and not in the footprint of ISS at that time.
Local QRM?
Since 145.825 is a simplex satellite packet frequency, could you be getting local QRM from ground stations on the "uplink"? It would be polite if ground stations only had their radios active when the satellite is in range. Automatic beacons just clutter the air waves and make it harder for folks who are actually manning their station during the pass.
Local QRM
To be honest, I wasn't aware of automatic beacons and that might explain the QRM the other night, but I've noticed that this freq. seems to always have more background noise than others above or below it. Perhaps because of all the activity that is there, even if at those freq's propagation is mainly line of sight, far away stations and space transmitters must be adding to that background through scatter and what have you. 73