1. Is this the best way or place to post such questions? 2. I have studied past posts and other sources but can't find answers to questions below. 3. I am trying to listen to ISS. N2Y0 and HeavensAbove list the same pass for my location today (FM14be, 16:39 local time, elevation 56 degrees) but AMSAT predictor says 4 degrees for that pass. Why the difference? 4. N2Y0 says up/down is 437.550/437.550, ASFK, inactive. HeavensAbove says 145.825/447.550 FM active. Who is right? How can I get correct frequencies to listen to? thanks Isaac
- N2Y0 says up/down is 437.550/437.550, ASFK, inactive. HeavensAbove
says 145.825/447.550 FM active. Who is right? How can I get correct frequencies to listen to?
Latest list of frequencies posted at: https://www.amsat.org/amateur-radio-on-the-iss/ The 145.825 MHz packet is most common operating mode. It has its on/off days depending on crew activity and radio health.
Watch the amsat-bb for ARISS school contact announcements. For example there is a school contact scheduled for next week - direct with a school in Ohio. The 145.800 MHz downlink will be good copy over a lot of the northeast and parts of the midwest.
Why the [time] difference?
Often related to differences in using local time and UTC on different sites. I'd go with the amsat predictor for now.
The ISS is large and relatively low, so it experiences a bit more atmospheric drag than most satellites. They periodically raise the orbit, which requires new orbital information. AMSAT updates the nasabare.txt information for the ISS as required. So depending on the source of information and when it was updated, you can get noticeable differences between prediction sites and tracking programs. As JoAnne said, go with the AMSAT site when in doubt.
73,
Alan WA4SCA
<-----Original Message----- <From: AMSAT-BB [mailto:amsat-bb-bounces@amsat.org] On Behalf Of <JoAnne K9JKM via AMSAT-BB <Sent: Friday, February 14, 2020 10:35 AM <To: amsat-bb@amsat.org <Subject: Re: [amsat-bb] Newbie Questions - ISS < < > 4. N2Y0 says up/down is 437.550/437.550, ASFK, inactive. HeavensAbove < > says 145.825/447.550 FM active. Who is right? How can I get correct < > frequencies to listen to? < <Latest list of frequencies posted at: <https://www.amsat.org/amateur-radio-on-the-iss/ <The 145.825 MHz packet is most common operating mode. It has its on/off <days depending on crew activity and radio health. < <Watch the amsat-bb for ARISS school contact announcements. For example <there is a school contact scheduled for next week - direct with a school <in Ohio. The 145.800 MHz downlink will be good copy over a lot of the <northeast and parts of the midwest. < < > Why the [time] difference? < <Often related to differences in using local time and UTC on different <sites. I'd go with the amsat predictor for now. < <-- <73 de JoAnne K9JKM <k9jkm@amsat.org <_______________________________________________ <Sent via AMSAT-BB@amsat.org. AMSAT-NA makes this open forum available <to all interested persons worldwide without requiring membership. Opinions <expressed <are solely those of the author, and do not reflect the official views of AMSAT- <NA. <Not an AMSAT-NA member? Join now to support the amateur satellite <program! <Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
Regarding the time difference, note that AMSAT has an arrangement with NASA to get orbital information directly from the Johnson Space Center. AMSAT predictions based on these data have proven to be extremely accurate over the years - even with the narrow beamwidths of 2395 MHz HamTV antennas.
Other sites often get their data from other sources which can become out of date in cases where the ISS adjusts its orbit.
Stick with AMSAT predictions and you will be in good shape.
And yes, this is exactly the right place for these kind of questions.
de KM1P Joe
participants (4)
-
Alan -
Jackie Dander -
JoAnne K9JKM -
Joseph B. Fitzgerald