Need a hand from our Linear Sat users.

[N9SOX]

Hi everyone,

I'm having a really hard time finding my SSB Signal in the Downlink of AO-7. I've tried the last few evenings that AO-7 has been in Mode B but have had no luck. I can hear everyone on the Bird just fine but when transmitting into the uplink, I can't seem to find my own signal.

I've tried CW and can generally find that with no problem. I've read that one can tune up using a CW, switch to USB and that should get you close. I've tried this and it worked once but I can't seem to do it again.

I've tried both manually tuning and using SatPC32. Anyone have any tips? I know I'm missing something here so any advice given would be appreciated.

[WD9EWK]

I'm having a really hard time finding my SSB Signal in the Downlink of AO-7. I've tried the last few evenings that AO-7 has been in Mode B but have had no luck. I can hear everyone on the Bird just fine but when transmitting into the uplink, I can't seem to find my own signal.

I've tried CW and can generally find that with no problem. I've read that one can tune up using a CW, switch to USB and that should get you close. I've tried this and it worked once but I can't seem to do it again.

I've tried both manually tuning and using SatPC32. Anyone have any tips? I know I'm missing something here so any advice given would be appreciated.

First of all, AO-7 is in mode B every other day. With the loss of the AO-7 activity logger, you can use the OSCAR Satellite Status page as a guide to what mode AO-7 is in. It has been switching modes around 2330-2345 UTC every day.

What radio are you using? Or radios, if you are working with two radios?

For AO-7 mode B, I typically like to start out at the beginning of the pass with my downlink radio at 145.960 MHz USB. I use USB to receive anything from the linear transponders, even in CW. Since I'm not using computer control, I don't want to park at the center of the passband, where most activity is centered around. I start my uplink around 432.132 MHz CW, tuning only the uplink until I hear myself on the downlink radio at 145.960 MHz. Once I hear myself, I switch the transmit radio to LSB and tune up a little bit (my FT-817NDs shift the VFO frequency by the CW sidetone frequency when going from SSB to CW - I use 700Hz as my CW sidetone frequency). As I start talking, I am adjusting the transmit radio's VFO until I clearly hear myself on the downlink, then start CQing.

If I decide to move somewhere else during a pass, once I have heard myself in SSB through the satellite, I will adjust both radios. If I move down from 145.960 MHz to 145.950 MHz, I would move the transmit radio's VFO up 10 kHz from whatever frequency is on the display. Then I try to transmit at the new spot, keeping in mind I may still have to tweak my uplink due to Doppler.

As for SatPC32, you may want to post a message on the AMSAT-BB list asking for the DOPPLER.SQF file from someone who successfully uses SatPC32 with the same radio setup as you have. At least that's a good starting point, where you can fine-tune the setup for your station.

If you are still working on getting SatPC32 set up, you may want to also work VO-52 passes. It's the same U/V setup as AO-7 mode B, but with better hardware on the satellite. If you get that working, then you should have a better idea of what you need to do with AO-7 in mode B. For VO-52, my starting points are 145.910 MHz USB on the downlink, and 435.231 MHz CW on the uplink. When you are able to hear yourself in SSB on VO-52, you should be in good shape for AO-7 mode B.

Hope this helps a little.......

73!





Patrick WD9EWK/VA7EWK
http://www.wd9ewk.net/

[N9SOX]

Hi Patrick,

Yes that helps quite a bit. I forgot to mention in my original post that I'm using a Yaesu FT-847. Let me think a bit more about the info you just posted and I'll come back with any questions. Thanks for the help!

I have heard myself in AO-7's downlink in the past and in fact made a contact not to long ago. I used the CW method in my original post to help find myself. I just can't seem to do it again.

[K6LCS]

We need to write and publish a FAQ, Patrick. You are a tremendous wealth of info on the birds ... and I am sure your personal In Box gets plenty of repetitive inquiries ... Heck, I am just "specializing" in the easy-to-work FM birds, and get plenty of repetitive inquiries.

Maybe there's an appropriate Wiki-like type of site that would be appropriate ...

Clint K6LCS
http://www.work-sat.com
909-241-7666

[N9SOX]

Is this a repetitive inquiry Clint?

[KO4MA]

Maybe there's an appropriate Wiki-like type of site that would be appropriate ...

How about AMSAT.org???

[WD9EWK]

We need to write and publish a FAQ, Patrick. You are a tremendous wealth of info on the birds ... and I am sure your personal In Box gets plenty of repetitive inquiries ... Heck, I am just "specializing" in the easy-to-work FM birds, and get plenty of repetitive inquiries.

I have thought about that. I enjoy answering questions about all sorts of satellite operating, but lately have done more typing about the SSB/CW satellites, since some (many?) still think it takes a lot of gear and $$$ to work them. Yes, a little more $$$ compared to a 2m/70cm FM HT and an antenna, but in reality it is not "too expensive". What I type about here, or talk about at hamfests or presentations, is exactly what I do on the air all the time.

At this point, I am at a disadvantage when it comes to writing about a station that many will use at home. I don't use a computer to control my gear, but I have the means to do that (SatPC32 software, cables connecting my netbook to the FT-817NDs). Until recently, I did all my satellite operating at a park, due to limitations in operating at the apartment I lived at. Now with a house and a back yard, I hope to get some more spare time on the weekends to play with the computer with the 817s.

73!




Patrick WD9EWK/VA7EWK
http://www.wd9ewk.net/

[WD9EWK]

Yes that helps quite a bit. I forgot to mention in my original post that I'm using a Yaesu FT-847. Let me think a bit more about the info you just posted and I'll come back with any questions.

You should be able to adapt what I do with two radios on your FT-847. You can tune the two VFOs, plus there is the "satellite" mode in the radio that may be useful. I will try to keep an eye on this part of the QRZ forums, or send me a private e-mail.

I have heard myself in AO-7's downlink in the past and in fact made a contact not to long ago. I used the CW method in my original post to help find myself. I just can't seem to do it again.

Just make sure the satellite is in the right mode, and give it another try. Unless someone is pumping the transponder with too much power, AO-7 has worked well for me with my 5W/log periodic setup.

73!




Patrick WD9EWK/VA7EWK
http://www.wd9ewk.net/

[N9SOX]

Thanks Patrick,

I sent you an email.

[W5PFG]

I use an FT-847 for all my linear satellite contacts. I run a serial cable between my laptop and the radio and run the SATPC32 software to control everything.

If you want to "manually" correct for Doppler, the radio is actually easy to do that as well. Basically you "find" yourself on the downlink/uplink and then hit the "Track" button (only in SAT mode.) I programmed AO-7, FO-29, and VO-52 into the SAT memories of my FT-847. This way you can make sure the radio is set correcting for inverting or non-inverting transponders.