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Re: Anyone have a handle on UL/DL Relationship

PostPosted: Thu Nov 28, 2013 7:24 pm
by wd9ewk
g0mjw wrote:I have noticed some stations able to stay on frequency and others drifting with the Doppler. Quite a few are rock solid and I would like to know how they manage it as I can't.


It is possible that some have their software tweaked sufficiently to stay spot on. Over here, many still need to do manual adjustments even when using computer control. Some may just be out of practice, if they haven't been working satellites lately. We are hearing many calls from long-time satellite operators who have not been on for some time.

I am firmly in the manual-control camp, and will slide onto the downlink frequency at the start of my transmissions. I am getting better at adjusting my transmit VFO a little before each transmission, to minimize the adjustment I have to do when I start transmitting. And I will be outside tonight trying another pass or two on the new bird.

73!

Re: Anyone have a handle on UL/DL Relationship

PostPosted: Fri Nov 29, 2013 2:17 pm
by 2e0sql
g0mjw wrote:I have noticed some stations able to stay on frequency and others drifting with the Doppler. Quite a few are rock solid and I would like to know how they manage it as I can't.


I'm just about managing to stay on the same frequency during a pass although I'm having to constantly correct SatPC32s uplink freq to make sure it stays that way , normally at the start of the pass I'm near enough spot.

I'm using the following in the doppler.sqf file:

Code: Select all
AO-73,145960,435149,USB,LSB,REV,0,0

Re: Anyone have a handle on UL/DL Relationship

PostPosted: Fri Nov 29, 2013 5:23 pm
by OH2FQV
You can estimate your downlink with this little formula.

UF - 581.111 MHz=DF ± doppler

UF = Uplink frequency (LSB)
DF = Downlink frequency (USB)

Unofficial info, from my own math and speculations

Any good?

: Jari / OH2FQV

Re: Anyone have a handle on UL/DL Relationship

PostPosted: Sun Dec 01, 2013 8:55 am
by wd9ewk
Hi!

More are getting a handle on this satellite. The evening passes over North America are still drawing crowds. One pass I worked tonight turned into a roundtable chat among several stations in the western and central USA. I've posted some videos - satellite audio combined with a slideshow - from several passes over the past week on my YouTube channel:

http://www.youtube.com/va7ewk

Most of the time, I use a pair of FT-817NDs. For one pass last night, I replaced one 817 with the all-mode receiver in a Kenwood TH-F6A HT (similar to the TH-F7 sold outside the Americas). Tonight, I tried an Icom IC-R20 receiver. I still have to get my FUNcube Dongle Pro+ working for this satellite, the next item on my "to do" list. :-)

I posted a message to the AMSAT-BB list referring to my videos, along with observations after working this satellite over the past week. Rather than copying that message here, I'll offer the following link to it:

http://amsat.org/pipermail/amsat-bb/2013-December/047415.html

The OSCAR Satellite Status Page at:

http://oscar.dcarr.org/

now has AO-73 as a valid satellite for reporting observations. Thanks to KD5QGR for updating the site tonight with the new satellite!

This new satellite has been fun to work. Lots of stations showing up, including some that have been away from the amateur satellites for a long time. And all of this from a little cube!

73!