Public Beta (2021 09 04)

kt4lh
Posts: 272
Joined: Sun Jan 12, 2020 4:27 am

Re: Public Beta (2021 09 04)

Post by kt4lh » Sat Sep 04, 2021 2:35 pm

I would suspect this is the first radio that has a satellite database built-in and does all of the frequency settings and doppler shifts for you. Interesting feature. I'd like to do more satellite work but I've never had any luck with it, always seems like I'm too slow on the draw or some big gun is over-powering me.

How is the GD77 in practice on working sats? I've heard of plenty of people using Baofengs for the easier birds to hit so I imagine the GD77 could only be better, especially now.

VK3KYY
Posts: 7478
Joined: Sat Nov 16, 2019 3:25 am
Location: Melbourne, Australia

Re: Public Beta (2021 09 04)

Post by VK3KYY » Sat Sep 04, 2021 9:40 pm

kt4lh wrote:
Sat Sep 04, 2021 2:35 pm
I would suspect this is the first radio that has a satellite database built-in and does all of the frequency settings and doppler shifts for you. Interesting feature. I'd like to do more satellite work but I've never had any luck with it, always seems like I'm too slow on the draw or some big gun is over-powering me.

How is the GD77 in practice on working sats? I've heard of plenty of people using Baofengs for the easier birds to hit so I imagine the GD77 could only be better, especially now.
I've had reports of people getting into the ISS and some other satellites using the long whip antenna that some GD77's came with

I ended up buying a small dual band beam, for about $100, then have no problem getting into AO-91, AO-92, ISS. Not tried SO-50 yet, but other people tell me that they have had success with SO-50 and other satellites.

N1KY
Posts: 84
Joined: Sun May 24, 2020 10:46 pm

Re: Public Beta (2021 09 04)

Post by N1KY » Sat Sep 04, 2021 11:28 pm

kt4lh wrote:
Sat Sep 04, 2021 2:35 pm
How is the GD77 in practice on working sats? I've heard of plenty of people using Baofengs for the easier birds to hit so I imagine the GD77 could only be better, especially now.
ISS is easy with GD77 and the Radioddity whip antenna. The uplink is VHF so you can mostly ignore its doppler shift and just tune the downlink frequency by ear during the pass. Also it doesn't spin/tumble in space so polarization fading doesn't occur.

I've also worked stations on AO-27 and CAS-3H with the GD77 and whip antenna. Like the ISS they are VHF-up which makes them easier for me.

I haven't had any success with the UHF uplink satellites. There is where I'm most excited about OpenGD77's auto doppler compensation. Looks like it's time that I build or buy a dual band beam antenna for satellite work.

VK3KYY
Posts: 7478
Joined: Sat Nov 16, 2019 3:25 am
Location: Melbourne, Australia

Re: Public Beta (2021 09 04)

Post by VK3KYY » Sat Sep 04, 2021 11:51 pm

N1KY wrote:
Sat Sep 04, 2021 11:28 pm
kt4lh wrote:
Sat Sep 04, 2021 2:35 pm
How is the GD77 in practice on working sats? I've heard of plenty of people using Baofengs for the easier birds to hit so I imagine the GD77 could only be better, especially now.
ISS is easy with GD77 and the Radioddity whip antenna. The uplink is VHF so you can mostly ignore its doppler shift and just tune the downlink frequency by ear during the pass. Also it doesn't spin/tumble in space so polarization fading doesn't occur.

I've also worked stations on AO-27 and CAS-3H with the GD77 and whip antenna. Like the ISS they are VHF-up which makes them easier for me.

I haven't had any success with the UHF uplink satellites. There is where I'm most excited about OpenGD77's auto doppler compensation. Looks like it's time that I build or buy a dual band beam antenna for satellite work.
I worked thought AO-91 and AO-92 with no problems at all.

The main problem using the satellites for anyone where are loads of Hams, is that most other stations will be running big base station rigs with lots more power, so anyone who doubles with you will whipe you out.

Having a beam allows you to get into the satellites when the elevation is low, and often this is when there is less traffic on the satellite.
This will of course depend on your location.

Even as it stands the firmware does work fine for Tx and Rx, its just the Max elevation calculation needs more work to get it accurate.
I'm working on how to do that now, and have a solution. But I need to make the solution not take too long to process, as the time to calculate the Max elevation can double the prediction time if I'm not careful.

If you want, I'll emial you an update which has a fix for this

VK3KYY
Posts: 7478
Joined: Sat Nov 16, 2019 3:25 am
Location: Melbourne, Australia

Re: Public Beta (2021 09 04)

Post by VK3KYY » Sun Sep 05, 2021 3:57 am

New public beta is now available

See this link https://www.opengd77.com/viewtopic.php? ... 838#p15672

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