Using two FeatherWeight Trackers with one Ground Station

[FredT]

Is there a way to use two FeatherWeight Trackers in a flight with just one Ground Station? For example, in a two-stage flight one tracker in the booster with a second in the sustainer.

One way I think it could be done is to connect the ground station to the tracker in the sustainer, without connecting to the one in the booster. Since the booster would likely land first, that tracker would go into "lost rocket mode" while the sustainer was still in the air. However, according to the manual the booster tracker wouldn't go into "lost rocket mode" until five minutes after landing and it's unlikely the sustainer would be in the air that long. Any FWT that flew later would receive and then relay the location to my ground station. I can see that working, but it lacks the certainty I would like. Besides, it's not clear to me that this function has been implemented in the Android App.

I was wondering if the Ground Station could simultaneously track two trackers if on A and B channels of the same frequency.

...Fred

 

[Adrian A]

Is there a way to use two FeatherWeight Trackers in a flight with just one Ground Station? For example, in a two-stage flight one tracker in the booster with a second in the sustainer.

One way I think it could be done is to connect the ground station to the tracker in the sustainer, without connecting to the one in the booster. Since the booster would likely land first, that tracker would go into "lost rocket mode" while the sustainer was still in the air. However, according to the manual the booster tracker wouldn't go into "lost rocket mode" until five minutes after landing and it's unlikely the sustainer would be in the air that long. Any FWT that flew later would receive and then relay the location to my ground station. I can see that working, but it lacks the certainty I would like. Besides, it's not clear to me that this function has been implemented in the Android App.

I was wondering if the Ground Station could simultaneously track two trackers if on A and B channels of the same frequency.

...Fred

You can switch back and forth using the new Featherweight UI app by just going to the devices page and clicking on the other tracker. That will automatically switch the GS to the channel of the new tracker. This way both trackers will be in 2-way comm mode.

If you put two trackers on the same frequency and with A/B timing, the GS will switch over to the GS coordination channel after each reception and you would only hear one. If you really want to do that and are willing to use a laptop to do it, you can send a serial command to the GS to use monitor mode, where it is just Rx-only on that channel.

 

[FredT]

You can switch back and forth using the new Featherweight UI app by just going to the devices page and clicking on the other tracker. That will automatically switch the GS to the channel of the new tracker. This way both trackers will be in 2-way comm mode.

If you put two trackers on the same frequency and with A/B timing, the GS will switch over to the GS coordination channel after each reception and you would only hear one. If you really want to do that and are willing to use a laptop to do it, you can send a serial command to the GS to use monitor mode, where it is just Rx-only on that channel.

Thanks for the info. I have yet to fly my FWTrackers, so I can only imagine various scenarios and try to make an educated guess on how to best use it. Experience tells me there's a lot happening during a two (or more) stage flight so it's best to minimize manual interactions during flight.

My current use case is to connect the GS to each tracker during pad prep so I know each is functioning properly. Once prep is completed and as I leave the pad area, I'd connect the GS to the upper stage tracker. When my flight is next to launch and as the LCO introduces the flight, I'd switch the GS to the booster tracker and follow it until it is on the ground (or near enough). At that point I'd switch the GS to track the upper stage until its touchdown. After both stages are on the ground the GS should have landing coordinates of both stages, and I could switch between the two trackers during recovery.

Does that sound like a reasonable plan? Is there a downside of the GS not connected to the booster tracker for that half an hour (or so) before launch while it is disconnected from the GS? Is there anything else I'm not considering?

One thing that puzzles me is why there is a two-way connection between GS and tracker during flight. What info is the GS sending to the tracker? Is GS just telling the tracker that is being tracked so it knows when go to "lost rocket mode"?

...Fred

 

[KBlack]

Adrian,
Is there a Windows app I can use with the GS? I like to run a non-handheld GS with a fixed antenna to capture flights as redundancy with my other trackers.

Also, with a PC GS there's far less chance of switching to another app then having to wait to re-connect via Bluetooth to the GS as there is with the Android app.

 

[Adrian A]

Thanks for the info. I have yet to fly my FWTrackers, so I can only imagine various scenarios and try to make an educated guess on how to best use it. Experience tells me there's a lot happening during a two (or more) stage flight so it's best to minimize manual interactions during flight.

My current use case is to connect the GS to each tracker during pad prep so I know each is functioning properly. Once prep is completed and as I leave the pad area, I'd connect the GS to the upper stage tracker. When my flight is next to launch and as the LCO introduces the flight, I'd switch the GS to the booster tracker and follow it until it is on the ground (or near enough). At that point I'd switch the GS to track the upper stage until its touchdown.

Fred,

The current version of the app is pretty good at switching a GS quickly between trackers. If it were me I would want to stay locked on the sustainer until after I see the upper stage on drogue and then I'd switch to monitor the booster. But it depends on the timing. If there is a booster deployment failure it could get on the ground pretty quickly. A dedicated GS for each tracker removes any of these tradeoffs.

After both stages are on the ground the GS should have landing coordinates of both stages, and I could switch between the two trackers during recovery.

Yes, you can track to the last known location whether or not the tracker has successfully transmitted recently.

Does that sound like a reasonable plan? Is there a downside of the GS not connected to the booster tracker for that half an hour (or so) before launch while it is disconnected from the GS?

That shouldn't be a problem. You can also practice switching between them before launch so you can get confident in the process.

Is there anything else I'm not considering?

One thing that puzzles me is why there is a two-way connection between GS and tracker during flight. What info is the GS sending to the tracker? Is GS just telling the tracker that is being tracked so it knows when go to "lost rocket mode"?

Yes, the latter. Also it lets the tracker know that it is clear to listen for lost rockets until its next transmission time.

 

[Adrian A]

Adrian,
Is there a Windows app I can use with the GS? I like to run a non-handheld GS with a fixed antenna to capture flights as redundancy with my other trackers.

Only a generic serial terminal. I use RealTerm. There is connection information is in the tracker manual. For this use case you would want to command it to monitor mode.

Also, with a PC GS there's far less chance of switching to another app then having to wait to re-connect via Bluetooth to the GS as there is with the Android app.

With the Featherweight UI, the Bluetooth connection continues while using other apps, at least the ones I have used.

 

[KBlack]

With the Featherweight UI, the Bluetooth connection continues while using other apps, at least the ones I have used.

That's certainly not my experience with my Samsung S23 Ultra, Samsung's flagship phone from last year, so I suspect more than a few people would have it.

I'll document my experiences when I have some more time.

 

[Adrian A]

That's certainly not my experience with my Samsung S23 Ultra, Samsung's flagship phone from last year, so I suspect more than a few people would have it.

I'll document my experiences when I have some more time.

Thanks for following up about that. When I was checking this out on my Android phone, I connected and then switched to GMail. I saw the blue LED continue its fast flashing to indicate that the connection is still there.

 

[KBlack]

I posted this elsewhere, but for anyone in the future that doesn't see that post, here it is in this thread:

I updated to Android app version 1.0.5 (270) and am VERY well pleased.

I'm now unable to recreate the difficulty with making and maintaining Bluetooth connections with my devices, and having a list of all my paired devices is an excellent touch.

Live mapping is just perfect.

With this update, I have confidence in it for this year's flying season. Can't wait for the good weather, and what new features are still in the pipeline.

Thanks Adrian!

 

[Adrian A]

Thanks so much! I agree that now with build 270, all the critical functionality for tracking is up and running the way it should be.

New features upcoming include scanning the channel list (started in build 270, but not really functional yet), and more accessibility for the lost rocket relay feature. I also have some features in mind for making it easier to monitor the flights of other rockets at the launch that are equipped with the Featherweight GPS tracking system.