tBeacon UHF (Ham band) beacon with GPS

Looks like this might be another case of hobby cross-pollination. It would be handy for areas without cell phone coverage. $50 without a GPS module which can be plugged into the tBeacon board via the provided connector. It's designed for use with R/C aircraft with GPS-enabled flight controllers, but it appears from the FAQ and the suggested wiring diagrams shown on his web page for various flight controllers that the unit is simply paralleling off the lines to the flight controller from the flight controller's external GPS module.

The basics:

- GPS position of craft using flight controller or dedicated GPS receiver
- activation via call from UHF handheld radio or by timer
- transmitted voice with GPS position along with RDF beacon tones
- easy configuration and calibration with a PC app
- optional module ($8) with loud buzzer and high intensity LED to simplify search in close proximity
- size 19x25mm. Weight: 2.5g. (weight is mostly determined by battery used)

EDIT: only 100mW TX power from module.

This has apparently been available in the R/C aircraft scene since early 2015, but I only today stumbled across it:

https://www.rcgroups.com/forums/showthread.php?t=2347391&pp=100&highlight=tbeacon#post30785392

https://www.rcgroups.com/forums/showthread.php?t=2371504&pp=100&highlight=tbeacon#post31080214

How does it work?:

https://tbeacon.org/?page=6&language=en&session=p3d6mgn2bu68kr3441jkm8tba4

FAQ:

https://www.tbeacon.org/?page=12

Docs and Downloads:

https://tbeacon.org/?page=8&language=en

Great find -- ordered one to play with......

Sooooooooooooooooo..................... DA here (devil's advocate) Your rocket goes oughta sight. When do you call? Once it's down, it may be too far to pick up a signal. Now what? You didn't see it come in, where to go to get close and pick up the
voice to tell you the lat/long? Call it too early and you get the position of where it's been. Can ya really remember the lat/long voice and write it down fast enough to input into a GPS to go to the last known position?

Sorry, I'll pass. It's best to have a device sending decodeable information that can be non-destructively held for use a' la APRS (Beeline and others), EggFinder, Altus Metrum etc. Having to do the guesswork of "when to call" isn't my cup of tea.
Converting the data to a point on a map directly is best which APRS and others can do. Fred it looks like you'll have to cobble together a GPS receiver/antenna for the device to work. Not worth the trouble $$$$ unless you have one in your junk box.

Kurt Savegnago

ksaves2 said:

Sooooooooooooooooo..................... DA here (devil's advocate) Your rocket goes oughta sight. When do you call? Once it's down, it may be too far to pick up a signal. Now what? You didn't see it come in, where to go to get close and pick up the
voice to tell you the lat/long? Call it too early and you get the position of where it's been. Can ya really remember the lat/long voice and write it down fast enough to input into a GPS to go to the last known position?

Sorry, I'll pass. It's best to have a device sending decodeable information that can be non-destructively held for use a' la APRS (Beeline and others), EggFinder, Altus Metrum etc. Having to do the guesswork of "when to call" isn't my cup of tea.
Converting the data to a point on a map directly is best which APRS and others can do. Fred it looks like you'll have to cobble together a GPS receiver/antenna for the device to work. Not worth the trouble $$$$ unless you have one in your junk box.

Kurt Savegnago

Click to expand...

No guarantee, but:

https://www.rcgroups.com/forums/showthread.php?t=2371504&pp=100&highlight=tbeacon#post31080214

Konstantin told me in our correspondence that he'd range tested a tBeacon from the center of his city at a range of 3km, or 1.8 miles. The result was successful two-way contact with the test unit. He said the signal was scratchy but audible. Given the urban environment, that's simply incredible.

Yes, you do need to attach a GPS RX module costing as little as $10 and a small lipo battery via the standard connectors provided for both.

The $215 Beeline GPS 70cm standard is 16mW, but "For extreme altitude, a 100mw version ($259) is available to extend your range to 250,000 feet or more! It does require the external USB interface to programming and battery charging." 100 mW is the output of the standard 70cm tBeacon.

The Eggfinder GPS KIT is $100, 100mW in the license free 900 MHz band, and the RX requires a PC to be used.

Some corrections Winston.

The Altus Metrum Tele-GPS at $200.00 sends out an APRS packet concurrently with their digital data. Any Ham
APRS receiving setup can track it. One doesn't have to buy an Altus Metrum dongle or the Tele-BT receiver. Those devices give one more rich information and voice call outs in realtime but not necessary. If any Ham needs a GPS tracker that's a bit smaller than a Beeline it is the one to get. I stuffed mine into a Go-Devil 38 nosecone just fine.

Beeline GPS price has dropped all versions and the 16mW job is perfectly fine for sport flying. Remember, one can have the BLGPS and Altus Metrum products save positions/GPS altitude to memory at a 1/sec rate if they want. The rate is programmable. The .kml files are downloadable after recovery for display on GoogleEarth.
Greg Clark does have a 900mhz no license required device that's already built.

EggFinder GPS system kit for the Holiday price of $100.00. Add a $6.00 or less B/T board and one can get two points on a map with datum line using GPS Rocket Locator. You are incorrect that a PC has to be used to track. It only has to be used if one uses the cheaper dongle receiver. I tracked at MWP13 and I found my rocket directly using a Nexus 7 2013 WiFi only and the EggFinder LCD. Maps can't be cached on GPS Rocket Locator but the program will run without an internet connection. North is up and one just follows the datum line to the rocket point. Alternatively, since the last known position is locked on the LCD screen, one can manually input the lat/long into any handheld mapping device and use that to navigate to the rocket. When close, the EF LCD will start beeping again with a final position. Since a 900mhz Yagi is compact to carry, I plugged that in after the rocket was down and was able to receive a new packet well before I could see the rocket on the ground. Put the duck antenna on and nothing.
Replaced again with the Yagi and finally could see its final resting place on the ground
as I got closer.

If a non-Ham wants to GPS track sport rockets, this system is the way to go. Research soldering SMT kits before purchasing and have a go or have Connor build it for you.

I do both types of tracking and APRS has the advantage of the handheld GPS like a Garmin
60Cs or CsX locking the rocket in on the pad and continuously computing a navigation solution
in real time as long as packets are coming across. Absolutely necessary? No, but really
makes it easy. It does cost but if one gets a used Yaesu VX-8GR and a used 60Cs or CsX, it
is more affordable these days. There's the formality of a Ham license but it's no worse than an L2 test and free practice can be had online. Don't want to do that route? That's O.K.
The EggFinder and the EggFinder TRS really are dastardly nice.

Oh, that rocket I tracked above was an Eggfinder TRS. Neat thing here is the LCD unit shows the continuity of the Main and Drogue ematches. When the current is sent to match in flight, the continuity light goes out and one can see that. Plus the altitude one sees is not the GPS altitude but the altitude from the baro chip on the board. This is generally considered more accurate than a GPS derived altitude. If an EggFinder GPS tracker is used, it will show the GPS altitude. Neat thing is the altitude goes to "0" before launch so the altitude one sees
is AGL with the TRS. (above ground level)

Kurt Savegnago

The cost of the tBeacon is $50. Add a GPS module for $20 and a lipo for $5 and your total hardware cost is $75. If you already own a 70cm or 2m/70cm handheld transceiver, that's a very cheap route to 100mW GPS location. If you don't have a HT, buy an appropriate, very cheap but entirely serviceable Baofeng (Pofung) HT, like the $25 UV-5R:

https://www.amazon.com/dp/B007H4VT7A/?tag=skimlinks_replacement-20

and you'll have a multi-use device: a HT for rocket tracking and ham use.

Another review:

https://fpvlab.com/forums/showthrea...on-in-Colorado&p=692823&viewfull=1#post692823

EDIT: I will say this - you need to know what you're doing electronics-wise and READ THE FAQ for the tBeacon. As an example of why you need to read the FAQ, you can't power the RED board directly with a lipo as they can go up to 4.1V when fully charged and the RED board wants a regulated voltage no higher than 3.6V. The BLUE board can be directly powered, but some of his comments/suggestions apply to use in R/C aircraft with flight controllers. I'm going to email him and tell him that he needs to write a FAQ more applicable to STAND ALONE use of the unit for rocketry.

Winston said:

EDIT: I will say this - you need to know what you're doing electronics-wise and READ THE FAQ for the tBeacon. As an example of why you need to read the FAQ, you can't power the RED board directly with a lipo as they can go up to 4.1V when fully charged and the RED board wants a regulated voltage no higher than 3.6V. The BLUE board can be directly powered, but some of his comments/suggestions apply to use in R/C aircraft with flight controllers. I'm going to email him and tell him that he needs to write a FAQ more applicable to STAND ALONE use of the unit for rocketry.

Click to expand...

I agree if one is going to go that route, they'll need some electronic skills and I might add if the Tbeacon needs 3.3V one would be smart to add a voltage regulator into the mix. The deal with it with R/C is the user usually has some idea when their, plane (FF or otherwise) or device goes out of sight and in what direction. With a rocket, it goes out of sight and you will have no idea where it is going. I've seen rockets end up drifting 180 degrees to the prevailing ground wind direction (with a GPS tracker on a ground mapping application). More prudent to have a continuous datastream. The voice thing is interesting though. $70 to $80.00 is pretty close to an EggFinder setup with no ham license required. Kurt Savegnago

Voice is nice since you don't need an APRS decode to get the packet into your hand-held GPS.
The RDF beacon is REALLY NICE - been begging Greg to add this for years.
Then when RDF has me close, a couple of pings with the HT to get the location is easy.

I actually see this being used as a backup finder - put it in the motor section while the BLGPS is in the NC - should you get a separation, you have a nice way to find the motor - in the sage at Brothers, this is big. I've got a Int-5 with a 5G98 motor out there somewhere......

FredA said:

Voice is nice since you don't need an APRS decode to get the packet into your hand-held GPS.

The RDF beacon is REALLY NICE - been begging Greg to add this for years.
Then when RDF has me close, a couple of pings with the HT to get the location is easy.

I actually see this being used as a backup finder - put it in the motor section while the BLGPS is in the NC - should you get a separation, you have a nice way to find the motor - in the sage at Brothers, this is big. I've got a Int-5 with a 5G98 motor out there somewhere......

Click to expand...

The problem with this device Fred is when it goes out of range. Unlike a streaming data set, is the last voice reported lat/longitude close enough to the final resting place so you are within range to ping it for another report?
If you don't write down that last position report or misconstrued what was said, you may be SOL. If one can set the device to constantly report aurally the lat/long, you have to hope you write down the last known good position.

If you are out of range, how are you going to get an updated bearing by RDF. No signal, no bearing. If you are out of range, no signal, no chance of pinging. Heck your 5 watt H/T might make it to the device but if you are out of range to receive the voice position, no update. Unless your H/T can record/playback stuff it might be hard to use in reality for
rocket tracking.

Again, I think it is more reliable to have a continuous datastream that will give you the closest landing position to where you can proceed to and if you don't see the rocket, it's likely nearby and by then, you'll have already received an updated packet.

Having to ping a device by chance is not a reliable method especially for a sight unseen flight. The last "reported" position might not be all that close and oh BTW, "Did you get that down?"

Fred, when you mean for Greg Clark to have an RDF mode for the Beeline GPS, do you mean if it loses satellite lock
for "X" amount of time it switches to RDF mode? That sounds good to me. I've been fortunate so far that my BLGPS
hasn't lost lock on the ground.

I will tell you though, when I flew my low powered Beeline GPS in this rocket the first time riding in the ebay:
(click for enlargements)



I received no Rf packets because of the metallic paint. Luckily the rocket landed within sight
and was recovered. Now since this was an older G-Switched BLGPS, I had it set to record and stop recording when it got to the beginning of the flight data. Since I didn't receive any Rf data, I said, "The heck with it. I'll break it down and shut the BLGPS off when I get home."
I had "auto-shutoff" selected for low voltage so I didn't care. Well the group decided to go for pizza so we drove east to a pizza place in Metamora, Il. When I got home I'd figure I'd look at the .kml file on the BeelineGPS anyways. Lo' and behold everything was recorded in the flight and positions to the parking lot of the pizza place and for the better part of the trip home until it stopped when it ran out of memory! The paint attenuated the 70cm Rf but did not attenuate the GPS satellite signals....
Go figure!? I had packets of the car in the parking lot when displayed on Google Earth.

Bottom line is the BLGPS was plotting packets from inside the rocket, while inside the passenger compartment inside my metal roofed car. I suspect the GPS receiving antenna was facing up but WOW! I thought that was something.

That second photo shows my half baked solution as I didn't want to have to strip the paint.
I have the BLGPS facing forward and have a connector to an aft bulkhead mount. At least the
antenna should be out in the open at apogee. It's one of those spring types. I haven't flown the rocket yet in this configuration.

In light of the recent rocketry death, I'm going to try to stuff a second altimeter in the ebay
for redundancy. (It only flew with a single MAWD) I think I have room for something small like a Quark. I used an extended coupler so it's doable now. Best regards, Kurt Savegnago

Quote from the email I received from the designer of the tBeacon. He will be creating a diagram on his site showing connections for stand-alone use.:

I do not recommend to power the GPS with the same LiPo. Doing so will GREATLY reduce standby time. You can calculate it yourself: given that average GPS module consumes around 50mAh (which is hundreds times more than the beacon itself), you'll need to use a battery of 50 * 24 =1200mAh to have standby time of 24 hours. A little too much IMHO

As an trade-off you can have two small LiPos: one for the beacon and one for the GPS. To the moment the second battery runs out, the rocket is likely to be grounded and not moving, so dead GPS won't be a problem because the beacon remembers last received location.

However, will the lipo connected to the GPS module be over-discharged or will the GPS module's current draw drop greatly when the RX no longer runs? I'm going to point that out to him. I'm no expert on GPS modules, but the tBeacon might be able to command the GPS module off upon landing via a firmware change. I'll ask.

EDIT: If GPS module shut-off is not possible or no firmware change is made to do so, one of these could be installed in-line with the GPS module battery pack:

Tenergy 32003 Protection Circuit Module for 3.6V / 3.7V Li-Polymer Battery (8.5A limit)

https://www.batteryjunction.com/prcimopcbfor.html?gclid=CJ2J_cL7sMkCFQ2QaQodaSsHTg

Wow, that was a quick reply from the designer:

Yes of course it can trash the LiPo, but in case of a serious S&R (I think he means "search and recovery" - W), the health of this LiPo will be the last thing to be concerned about, IMHO. Moreover you can use a LiPo with PCB (protection circuit) which prevent overdischarge (as I mentioned above - W). BTW, most of LiPos on the market have these, except high-discharge LiPos used in RC models (not correct; in my experience, only those made for toy-grade consumer R/C equipment do; the largest capacity lipo I've seen with that sort of circuit is a 380mAh single cell (3.7V) one; even small single cell lipos from major R/C hobbyist suppliers like Hobbyking DO NOT have the protection circuit - W)

Shutting off the GPS is not very complicated task, however it requires some specific GPS module or some additional circuitry. And a support from the firmware of course. I have this task in my TODO (a beacon with built-in GPS), but can't tell the estimate yet, sorry.

I know for certain that these packs have over/under-charge protection circuits and the ones I received are authentic Tenergy brand which I tested and found to be accurately capacity rated (a lot of lipos not bought directly from a known reputable retailers aren't):

https://www.amazon.com/gp/product/B00HQSAF8Q/?tag=skimlinks_replacement-20

They have the correct micro-Losi connector wired with the correct polarity to plug into the tBeacon's stock connector. 380mAh would run the tBeacon for a very, very long time in its standby mode with the current drain increasing only whenever the tBeacon's TX was triggered by your HT transmit trigger. At the 50mA drain of the GPS module mentioned by the author, the GPS module's 380mAh lipo would operate for 5 hours (to be conservative) on a 380mAh lipo, but since, as the designer said, the tBeacon retains the last GPS fix and uses that when transmitting its location, that five hours would be plenty since your rocket flight isn't going to take a total of five hours of pad and on-'chute time.

What you get with the tBeacon:

If the GPS is shutoff once it's on the ground, can you command the device blindly to turn back on and give you a lat/long? If it lands a distance away from where you received the last position report, how are you going to know where to look if you can't actively get a beacon off of it? If you have a timer set, you'd have to blindly stand around and wait to see if the voice comes back or you have to hope you're within range to ping for a report. You'll be fine if you're within range.
If not, now what do you do? The device is effectively lost with your rocket. Waste of time effort and money.

Now you say you have to carry a larger battery due to the higher power requirements. Sort of negates the advantage of the small size.
Let's see, small unit, needs a GPS receiver, larger battery and voltage regulator.

I certainly hope a neophyte doesn't fall for the false promise that this is an easy, cheap tracking solution because it isn't. If the "verbal" position report is on the edge of reception, one might not get the position report written down and they won't even know if this position is even close to the final landing spot of the rocket.

R/C stuff and hobby drones are not likely to be flown sight unseen at distances that rockets might drift. Sure the real pricey stuff with virtual reality, auto-pilots and GPS tracking don't need this Tbeacon because they most likely have the auto-return program capability if the link is lost. If it goes into failure mode, the "brain" tells it to go back to a pre-programmed position. (Most likely a starting location)

You want a pretty darned good tracking solution with cached maps/photos for "off grid/internet" use? Get a Tele-GPS and Tele-BT for $355.00. Pair with your Android device and you can "see" how close your rocket landed to that barn even though your rocket went out of sight and none of the events were seen.
Oh, it has a voice reporting output too if you want something that talks to you.

I've had six "sight unseen" flights so far and it was the continuous datastream being reported is what affected good recoveries. This Tbeacon wouldn't have been worth squat in those situations Use it for "backup"? What for? it wouldn't be effective for sight unseen flights and heck one can just duct tape an extra RDF beacon
on a shockcord for more effective backup than this thing. Kurt

ksaves2 said:

If the GPS is shutoff once it's on the ground, can you command the device blindly to turn back on and give you a lat/long? If it lands a distance away from where you received the last position report, how are you going to know where to look if you can't actively get a beacon off of it? If you have a timer set, you'd have to blindly stand around and wait to see if the voice comes back or you have to hope you're within range to ping for a report. You'll be fine if you're within range. If not, now what do you do? The device is effectively lost with your rocket. Waste of time effort and money.

Click to expand...

The tBeacon transmits the last lat/lon fix when triggered to do so or it can be set to periodically TX. The range is supposedly great and given the typical terrain in areas without cell coverage where you might use it (I'm thinking of desert), should have very long range. Since I guess you're not reading at the links I've provided, here's an excerpt from one of them. He bought the SMT kits, so he's not an electronics beginner:

I built two of these so far, have been testing them for a couple weeks. It's a very efficient 100mw beacon activated by a tone call from your radio (a UHF transceiver), has voice annunciation of RSSI, GPS Coordinates, voltage, etc, it charges a dedicated 1S battery from your 5V source, and has a ton of configuration options. It is tiny, only weighs 2.5 grams, it can run for weeks off a 300mah battery, and has excellent performance. I had it mounted to my Cinetank in my garage over in Village Seven, and was able to hit it with my 5W transceiver & my home made handheld yagi 7.5 miles away across urban clutter with hills in between. I actually put it to use this weekend- my Cinetank VTx shut down when I was about 2500 feet out. We walked right up to it thanks to the TBeacon on board. One of the nice things about it is it just plain works- it can 'sniff' your existing onboard GPS whether it be NMEA or UBX, doesn't matter what Baud rate- the tBeacon figures it out. I'm working with the inventor on supporting Vector- we've got code in the works for that.

Now you say you have to carry a larger battery due to the higher power requirements. Sort of negates the advantage of the small size. Let's see, small unit, needs a GPS receiver, larger battery and voltage regulator.

Click to expand...

You refer to the extreme example given by the designer, but apparently didn't read my later comments. The combination would be a 2.5g tBeacon, ? gram GPS module, a 14g over/undercharge protected 380mAh lipo cell of the type I linked to above for the GPS module supplying, very conservatively, 5 hours of 50mAh GPS module operation, another battery of the same type or smaller for the tBeacon module, a 300mAh battery supplying weeks of standby (waiting for tone trigger) operation according to the above reviewer.

I certainly hope a neophyte doesn't fall for the false promise that this is an easy, cheap tracking solution because it isn't.

Click to expand...

I don't suggest this for the neophyte as a plug and play unit and I warned about that with a note above where I said you need to know a bit of electronics to use it if you choose to.

My only caution is you better do an adequate range check with your rocket lying on the ground in your expected terrain. 100mW is decent output but if it lands
in a slight depression or behind a slight rise, you'll be surprised by the attenuation. I've had small rockets visually disappear at .6 of mile out. None of the events seen. Small rocket with 36" chute and datastream coming in was able to direct our eyes where to look. Still couldn't see it under the main. Walked right up to it and confirmed what the incoming data was telling me. Main chute was out.

If your rockets are going to land within range of the Tbeacon, you'll be fine. Interrogate and it tells you where it's at. A datastream gives one where it's headed
and will likely get a last position report 50 to 200 feet off the ground. That gives one a better fix where to start their search.

One other caution. 100mW might interfere with a deployment device. I do think it is a good idea that the device can be programmed to transmit at given times besides being interrogated. Would likely want to avoid pinging between apogee and main events then. After the last pyro device has fired, wouldn't have to worry. I've witnessed several malfunctions attributed to Rf interference. P6K (anyone still use those?) Adept 22's and the AIM USB are prone to Rf interference.
I will credit Entacore as they do have the caution in the altimeters manual. Best of luck and remember to do a ground range test.

The failure scenario is a rocket that remains sight unseen and lands someplace out of range of the Tbeacon. I mean if you catch sight of the rocket in descent
1.5miles away you can ping it before it lands to get a fix. That will probably get you close enough to get another fix/report. If you can't see anything of the flight, it's a crapshoot. I suppose you can run a simulation of the flight and run a stopwatch. If you don't see it, ping it when you predicted it to be a few hundred feet off the ground. But then again, if you know the flight is going that high and that far, a different tracking method is more prudent to get a good recovery.

Keep us posted as to how it turns out. I'd like to see how effective it is with rocketry. Kurt Savegnago

ksaves2 said:

My only caution is you better do an adequate range check with your rocket lying on the ground in your expected terrain. 100mW is decent output but if it lands
in a slight depression or behind a slight rise, you'll be surprised by the attenuation. I've had small rockets visually disappear at .6 of mile out. None of the events seen. Small rocket with 36" chute and datastream coming in was able to direct our eyes where to look. Still couldn't see it under the main. Walked right up to it and confirmed what the incoming data was telling me. Main chute was out.

If your rockets are going to land within range of the Tbeacon, you'll be fine. Interrogate and it tells you where it's at. A datastream gives one where it's headed
and will likely get a last position report 50 to 200 feet off the ground. That gives one a better fix where to start their search.

One other caution. 100mW might interfere with a deployment device. I do think it is a good idea that the device can be programmed to transmit at given times besides being interrogated. Would likely want to avoid pinging between apogee and main events then. After the last pyro device has fired, wouldn't have to worry. I've witnessed several malfunctions attributed to Rf interference. P6K (anyone still use those?) Adept 22's and the AIM USB are prone to Rf interference.
I will credit Entacore as they do have the caution in the altimeters manual. Best of luck and remember to do a ground range test.

The failure scenario is a rocket that remains sight unseen and lands someplace out of range of the Tbeacon. I mean if you catch sight of the rocket in descent
1.5miles away you can ping it before it lands to get a fix. That will probably get you close enough to get another fix/report. If you can't see anything of the flight, it's a crapshoot. I suppose you can run a simulation of the flight and run a stopwatch. If you don't see it, ping it when you predicted it to be a few hundred feet off the ground. But then again, if you know the flight is going that high and that far, a different tracking method is more prudent to get a good recovery.

Keep us posted as to how it turns out. I'd like to see how effective it is with rocketry. Kurt Savegnago

Click to expand...

Thanks. However, what you warn about is the same for any 100mW 70cm GPS/TX unit. The range for the BeeLine GPS is 10 miles line of site for their 16mW unit, >40 miles for their 100mw version. The tested range (by one of the reviewers linked to above) for the tBeacon with a 5W HT and a DIY directional antenna is 7.5 miles with the tBeacon located inside of a garage with an urban area and hills between it and the HT.

THE major issue with the tBeacon that I didn't know when I first investigated it after seeing it because the designer showed a stand-alone configuration of it on his web page is that his tBeacon firmware does not send a sleep command to the external GPS module because he's counting on the R/C aircraft's flight controller to do that when the aircraft's battery gets low. That wasn't evident without investigation as he doesn't actually state that as far as I can find anywhere on his web page.

The workaround is either to use one of those over/under discharge protected 380mAh single cell lipos I linked to above to power BOTH the tBeacon and the attached GPS module, getting at least five hours of operation of both OR to come up with a more involved DIY setup (still not complex for an electronics-savvy person to set up) with one such lipo assigned to the GPS module and another for the tBeacon, allowing five hours of operation for the GPS module and weeks of operation for the tBeacon which will hold and transmit when queried or at programmable intervals its last GPS fix it received before the GPS module's lipo was cut off by the cell's over-discharge protection circuit.

I'll post a hardware block diagram for both configurations once I confirm them with the tBeacon designer (just to be absolutely safe). I don't need a GPS unit myself and was just suggesting this one for possible use by others just as I did with the $40 GPS unit which uses the cell phone system which, like this unit, I found mentioned in an R/C aircraft hobby forum, a device which others here then bought and successfully used:

$40 (US source) GPS tracker

https://www.rocketryforum.com/showthread.php?124527-40-(US-source)-GPS-tracker