# New tracker range test result

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#### kjs

##### Well-Known Member
TRF Supporter
Thanks for the recommendation. I see many in Ebay. What's your recommendation for storage (8, 16 or 32)? My plan would be to use it as a Wifi only device. Do you see any problems with this approach?
I have an iPhone 5c Model ME508LL w/ 13GB (odd number) but with 5GB available. it has no SIM card (so wifi only now). based on the 5GB available (and I don't put much else on here) I would recommend the 16GB (not the 8GB). FIP doesn't take much but you may install other stuff.

TRF Supporter

#### jderimig

This in some cases can be done by declaration, but offering complete transmitters for "License Free" applications requires the transmitter be certified, even if the individual modules are FCC "pre-approved" or compliant.
Allen you are exposing the "dirty little secret' of the "license free" products in this hobby. The FCC is probably not going to bother the users but the manufacturers might have a little bit of legal "exposure" with these devices in how they are representing them (as you have brought up).

You cannot "self declare" unless you have the capability to do the measurements in-house that a certification lab would do. You cannot self-declare solely on the basis on using FCC certified modules and best practices. You got to measure, document and retain the documentation.

Fortunately it is unlikely the FCC will bother with us, but if there is a case of interference, the FCC might come down hard.

#### Micro-Trak

##### Member
TRF Supporter
I certainly do not want to urinate in anyone's pool on this, I just think its easier on everyone if these devices are sold as "Ham Transmitters" ....Not that I would ever suggest it, ( Perish the thought!) but if someone was to operate a 900 MHZ "Ham Transmitter" putting out "License Free" power levels, without actually having a Ham License, it would easily fall into the "My bad-so sorry" area. The transmissions are indistinguishable for all practical purposes from many garage door openers. ( Although using garage door openers is not likely to result in theoretical $10,000 fines per every day of operation of unlicensed transmitters) A ham license makes it nice and legal, and though it costs ten bucks, its still cheaper than a$10K fine. Selling non-approved radios as "license free" is the kind of thing that keeps FCC employees driving new Maserati. Recently a company selling Drones with ham transmitters was slapped with business-ending FCC fines and forfeitures. It just does not make sense, its better to offer the devices as "Ham Transmitters" and let the end-user sin his own sins. Rocketry and Radio are largely about experimentation (...and blowing sh**t up...) and handling the radio part under the auspices of amateur radio is basic safety.

#### ksaves2

Yeah, and I'm getting averse to Android devices 'cause they're leaking data daily when I have everything locked down. Google tracks the daylights out of us and uses the mobile network even when wifi is available. It's hard if one wishes to be
frugal with data. I'm locking out tracking and find my device for now and see if the 7mb or more a day data leak isn't cut down. Yeah, I've locked everything to wifi and If I need an app on mobile, I turn it on, use it and then turn it off.
There are background Android apps that aren't easy to find that big brother uses to keep tabs on us on our dime. I could live with it if it was wifi only but this stinks. Kurt

#### ksaves2

I certainly do not want to urinate in anyone's pool on this, I just think its easier on everyone if these devices are sold as "Ham Transmitters" ....Not that I would ever suggest it, ( Perish the thought!) but if someone was to operate a 900 MHZ "Ham Transmitter" putting out "License Free" power levels, without actually having a Ham License, it would easily fall into the "My bad-so sorry" area. The transmissions are indistinguishable for all practical purposes from many garage door openers. ( Although using garage door openers is not likely to result in theoretical $10,000 fines per every day of operation of unlicensed transmitters) A ham license makes it nice and legal, and though it costs ten bucks, its still cheaper than a$10K fine. Selling non-approved radios as "license free" is the kind of thing that keeps FCC employees driving new Maserati. Recently a company selling Drones with ham transmitters was slapped with business-ending FCC fines and forfeitures. It just does not make sense, its better to offer the devices as "Ham Transmitters" and let the end-user sin his own sins. Rocketry and Radio are largely about experimentation (...and blowing sh**t up...) and handling the radio part under the auspices of amateur radio is basic safety.
Doesn't matter whether one has a Ham license or not with these devices. I was working with some 3DR transmitters that allegedly were >100mW out on 33cm and 70cm. I couldn't figure a way to use a cheap GPS and get my callsign in the NMEA
strings to stay legal so I abandoned it. Plus I didn't get a chance to see if I could set the devices to one way communication. Sure it was interesting to see the signal strength at both ends but I preferred that the 3DR/GPS tracker simply send the NMEA strings without listening for a return from the ground station. The advantage with this setup would be if you lose a \$30.00 GPS tracker, it's a lot easier to swallow. Other problems I couldn't work out was that the "generic cheap" GPS chipsets were not very much programmable (at least for me) to get my callsign in.

When I say doesn't matter whether one has a Ham license or not, if the maker touts the device as being approved, rocket fliers out in the middle of no where flying 100mW or lower powered 33cm/ISM/900Mhz devices is unlikely to jerk the 'ire of anyone period. Sure on 70cm might P.O. some Hams and more likely to get caught but with spread spectrum I doubt anyone would catch 'em.

The maxium power output to the antenna on the ISM bands is here: http://afar.net/tutorials/fcc-rules/
For 900Mhz it says 1 watt so nobody using a 100mW rocket tracker is offending the Federal Cookie Cutters. Sorry Allen I think my brethren using these devices are not in jeopardy. I don't think any of the transmitting components generally
available are violating the power output rules. Plus the do-it-yourselfers here aren't going to be trying to bust 1 watt using an amp. Just too heavy for an average sport rocket that isn't going to be flying far.

Hey Allen, I still have a pile of Byonics stuff I experiment with. Was going to launch an 8 watt MT8000 up in a rocket until I had some problems with Rf dorking some of the deployment altimeters of the time (with other lower powered trackers) and the fact that that high altitude balloon guys have done it all the time already. That took the wind out of my sails and I unlikely will ever be able to create a project that would need something like that. A 100mW,70cm Beeline GPS I have already pretty well outstrips my rocket skills for anything I can come up with.

Kurt (yeah I got a General ticket too)

#### OverTheTop

##### Well-Known Member
In Australia the regulations for the 900MHz ISM band is stated to be license free and no applications for licenses are needed. It would surprise me if things were much different in the USA.

Note that the 900MHz devices are covered under the LIPD class, but 435MHz devices are not. There is no guarantee of service when using these ISM bands. Interference is a real possibility, as the frequencies are permitted to be used by industrial, scientific, and medical devices.

Legislation Here:
https://www.acma.gov.au/Industry/Sp...ass-licences/lipd-class-licence-spectrum-acma
LIPD class licence
Radiocommunications (Low Interference Potential Devices) Class Licence 2015 (the LIPD Class Licence)

Class licences

Class licences authorise the use of many radiocommunications devices within the conditions of the licence as well as the provisions of the Radiocommunications Act 1992 (the Act).

Under a class licence, all users share the same spectrum segment and are subject to the same conditions. A class licence governs equipment standards and the frequencies that may be used, and can specify other technical and operational parameters. You do not need to apply for a class licence and no licence fees are payable.

The Low interference potential devices (LIPD) class licence
The LIPD class licence authorises you to operate a wide range of low power radiocommunications devices in various segments of the radiofrequency spectrum. The class licence sets out the conditions under which many types of short-range devices may operate. These conditions always cover frequency bands of operation and radiated power limits. Other conditions are applied as necessary.

Examples of equipment covered by the LIPD class licence include garage door openers, home detention monitoring equipment, spread spectrum devices (see below) and personal alarms. These devices do not require individual frequency coordination for interference management.

#### jderimig

In Australia the regulations for the 900MHz ISM band is stated to be license free and no applications for licenses are needed. It would surprise me if things were much different in the USA.
Allen's discussion was not about licenses to use, but that in the US, devices sold to operate in the license free bands need to be certified. In the US that regulation is Part 15.

Users that are not licensed must use certified devices. Otherwise they will need a license.

#### OverTheTop

##### Well-Known Member
As I said, it would surprise me if it were different. Not impossible. I have seen similar things where certification of modules does not remove the requirement for equipment using them to be also certified, but it usually is not in the relatively unregulated areas. I am not that familiar with FCC regs, hence only my provision of the Oz regulations .

#### jderimig

but it usually is not in the relatively unregulated areas. I am not that familiar with FCC regs, hence only my provision of the Oz regulations .
In the US 900mHz IS regulated, as well as all the ISM bands. The regulation falls on the devices and manufacturers as opposed to the users. I have to believe things is Oz is similar.

#### manixFan

##### Not a rocket scientist
...Selling non-approved radios as "license free" is the kind of thing that keeps FCC employees driving new Maserati....
That's the funniest thing I've read in a long time. The last time I checked fines didn't go directly to government employees.

Tony

#### OverTheTop

##### Well-Known Member
In the US 900MHz IS regulated, as well as all the ISM bands. The regulation falls on the devices and manufacturers as opposed to the users. I have to believe things is Oz is similar.
You are probably right John. I personally have not had to look into that area from a manufacturing POV because we don't do products that are "intentional emitters". Having seen what CSA (usually tougher than FCC) do with power supplies it makes sense that it would be similar for Tx as well. Certify the module, and then certify the system to make sure the module still behaves as intended.

My intention for this product has always been for them to be FCC certified so that a HAM license is not required for operation in the U.S. The product uses certified FCC modules, and the certification in the US at the system level is in progress with no issues expected. The time and cost to do that is not trivial, but it's not a deal-breaker either. For non-US countries, we will likely need to address this on a case-by-case basis, depending on the specifics of that country's laws and regulations. A HAM license may be required for those users, since the number of unit sold would not justify individual certification for countries with < 100 customers.

In other news, here's a plot taken from a test flight last week that was checking out the new on-board logging feature:

In the chart above, the # of satellites is on the right. I multiplied the satellite count data by 10 in order for it to show up. All measurements are at 10 Hz, which is the speed that the GPS outputs solutions. A GPS lock was maintained throughout the flight. The accel plot is derived based on the vertical velocity. It's kinda junky during the burn, but during the coast it seems to capture the drag acceleration pretty well. The descent rates are nice and clear. The horizontal and vertical velocity that were recorded looked good enough during the coast that I decided to see what a derived flight angle would look like:

Again the flight angle looks bogus during the beginning of the burn, but then during the end of the burn and throughout the coast, the flight angle looks very reasonable. You can see that it goes through 90 degrees right at apogee. I think for this particular flight it could have been used for an airstart staging check, though other flights with higher Gs haven't looked as good as this. If I do an integrated flight computer with GPS, we could use this an an airstart inhibit along with the GPS lock quality and a comparison check between the GPS velocity and the accel-derived velocity.

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#### Buckeye

##### Well-Known Member
Awesome! Is this finally the end of barometric and accelerometer flight computers?

It will be a file, accessible via the phone app. Kevin is working on that part. There is also data that is recorded by the phone as it receives it, that is stored as well. We are thinking about having both forms available for playback as well as export.

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#### dshmel

##### Well-Known Member
Excellent !!

Awesome! Is this finally the end of barometric and accelerometer flight computers?
Well, the acceleration can be measured a lot better by accelerometers, and barometric pressure is a safe way of estimating altitude locally that is more reliably available, so I would not expect them to go away any time soon.

#### manixFan

##### Not a rocket scientist
It will be a file, accessible via the phone app. Kevin is working on that part. There is also data that is recorded by the phone as it receives it, that is stored as well. We are thinking about having both forms available for playback as well as export.
Can you give us an idea of what data will be logged where? Obviously having the GPS data logged will be super useful as well as all the other usual data. Currently I'm using the built-in screen recording feature of the iPhone to playback flights. I record audio as well which allows me to annotate flight events in real time which can be really useful to try and correlate to unusual events when looking at the data. Also being able to playback the flight via your software will be great to add to onboard video.

Tony

Can you give us an idea of what data will be logged where? Obviously having the GPS data logged will be super useful as well as all the other usual data. Currently I'm using the built-in screen recording feature of the iPhone to playback flights. I record audio as well which allows me to annotate flight events in real time which can be really useful to try and correlate to unusual events when looking at the data. Also being able to playback the flight via your software will be great to add to onboard video.

Tony
All packets received by a ground station will be recorded onto the phone by the app. These are only coming in at the rate that you can see as you watch it real-time, which is around once per second. All the data received from the tracker, including packet counters, signal strength in both directions, data from lost rockets, if any, etc.is recorded.

On-board the tracker, the tracker logs GPS position, altitude, horizontal and vertical velocity, heading, satellite strength summary, and battery voltage ten times per second, along with the signal strength of the last received GS-to-tracker ack packet. It stores up to about 5 minutes of flight data to non-volatile memory, and doesn't erase it until it detects a new launch. Data from the most recent 5 seconds before launch detection saved in RAM and then recorded to non-volatile memory after landing is detected. The recorded tracker data will be downloaded to the phone pretty slowly, since the Bluetooth Low Energy is pretty slow.

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I thought I'd give a status update on some of the advanced features that are in the pipeline:
Data logging: There will soon be two types of logged data:
1. 10 Hz flight data that is recorded by the tracker and available for download after recovery
2. Data recorded by the phone as it comes in, generally 1 Hz
10 Hz data logging locally on the tracker has been flight tested. Transmitting the recorded data back to the phone is mostly done.
Phone-recorded data has been getting stored in our development testing versions since August. Getting the data into files so that it can be transferred off of the phone by USB or email is still in work, but it's getting closer.
Handling of files recorded by the tracker and by the phone itself so they can be transferred over USB or emailed is in work.

Over the horizon relay (lost rocket): The first partially-functional tests of the lost rocket functionality were at BALLS 2017. Starting in August 2018 we have been doing flight tests with it in development versions of the phone app. There are a couple of minor kinks to work out on the interface between the phone and ground station (GS)/tracker, but the communication links from lost rocket to flying rocket to GS to the other GS are all working. I'm looking forward to this feature making it out into the wild.

Public telemetry: Development phone app versions that provide access to other rocket's telemetry are in test.

Multi-stage tracking: A version of multi-tracking has been available to users since June, with a iOS selection wheel used for picking which tracker the GS will listen to. A new improvement is that we are tweaking the channel frequency assignment strategy so that one GS will be able to listen to, and record, all the packets from 2 trackers no matter which one is displayed live. This will enable one GS to do double-duty for recording and recovering 2 stages. Alternatively, if a user does have 2 ground stations, he or she can pair one for live data with one stage and the other with the other stage, while data from each stage is being recorded to both ground stations for redundancy.

New advanced feature, extra low power consumption for lost rockets. After a tracker detects that it has been launched, if if loses contact with its ground station due to terrain in the way, such as after landing, it goes into a lost rocket mode. In lost rocket mode the tracker transmits on both the lost rocket channel (so other rockets will relay its data) and on its original channel that its ground station is listening to. I'm currently working on reducing the average power used in lost-rocket mode to extend the time available for recovery. I should be able to at least double the current lifetime for a given battery size while in lost rocket mode, and a factor of 10x may be possible. if it's double time, then a standard small 400 mAhr battery should be able to last for more than 10 hours.

#### TonyL

##### Well-Known Member
I like the new data recording features very much, am really looking forward to being able to get the data. I am thinking I will use two ground stations for a two stage as switching back and forth is really more practical after stuff has landed.

The predicted impact point seems as valuable as the current position, more so after something has gone wrong. A saved history of that calculation would be very valuable for searching for a lost rocket as the last estimate may or may not be the best estimate. Also thinking out loud, a weighted average on the trajectory data favoring more recent points would help account for wind forces on a ballistic trajectory. If you want to get fancy, a kalman filter would be a fine candidate for the algorithm.

It would be nice to display both sets of coordinates. On my tablet there is a ton of room on the display. I get that a phone may be more crowded, but a few radio buttons for things like dual display and gps units could be on a settings page.

One question on altitude: what is the limit for the GPS module? Many units are only calibrated for up to less than 60kft and the adafruit one only claims 125kft.

br/

Tony

#### Bobfly

This all sounds great! I test flew your GPS Tracker for the first time at our METRA Club’s last launch of the year. That was during the first week of November.

Your unit worked great for tracking. I can’t wait for the data logging software to be setup.

Have a good holiday and keep up the good work.

All the best,
Bob

#### KBlack

##### AP abuser, Lithobraker, Shaper of plastics.
Has development for the Android app fallen off the radar? What is the minimum iOS device required to run iFIP?

I like the new data recording features very much, am really looking forward to being able to get the data. I am thinking I will use two ground stations for a two stage as switching back and forth is really more practical after stuff has landed.

The predicted impact point seems as valuable as the current position, more so after something has gone wrong. A saved history of that calculation would be very valuable for searching for a lost rocket as the last estimate may or may not be the best estimate. Also thinking out loud, a weighted average on the trajectory data favoring more recent points would help account for wind forces on a ballistic trajectory. If you want to get fancy, a kalman filter would be a fine candidate for the algorithm.

It would be nice to display both sets of coordinates. On my tablet there is a ton of room on the display. I get that a phone may be more crowded, but a few radio buttons for things like dual display and gps units could be on a settings page.

One question on altitude: what is the limit for the GPS module? Many units are only calibrated for up to less than 60kft and the adafruit one only claims 125kft.

br/

Tony
I agree with all about the estimated landing position. It's on the to-do list, but not as high as some of the other items.

The GPS receiver data sheet says that 50 km (164042 feet) is the maximum altitude that the GPS will report. This is consistent with Jim Jarvis's experience in his recent very-high altitude flight with another uBlox receiver. At that altitude, extrapolating the position and velocity with a zero-drag assumption would probably get you pretty close to the true altitude.

Has development for the Android app fallen off the radar? What is the minimum iOS device required to run iFIP?
Android is still on the horizon, but we decided to implement the full feature set on iOS first, so not much work has happened on Android yet. We're recommending at least iOS 10 because it supports the larger Bluetooth packets that we plan to include in future releases.

#### GrouchoDuke

##### Well-Known Member
It's great to see the work progressing on the internal logging. Can't wait to try that out.

#### BDB

##### Absent Minded Professor
I bought the package with two trackers and a base station for some eventual two-stage fun. It seems to me that the two trackers should be set to different frequencies, but I can't figure out how to get the ground station to monitor both frequencies.

No worries. I won't be ready for any significant two-stage stuff until the middle of next year. Thus far, the set-up has been very straightforward. I'm hoping to fly the tracker in a test rocket this weekend.

I bought the package with two trackers and a base station for some eventual two-stage fun. It seems to me that the two trackers should be set to different frequencies, but I can't figure out how to get the ground station to monitor both frequencies.

No worries. I won't be ready for any significant two-stage stuff until the middle of next year. Thus far, the set-up has been very straightforward. I'm hoping to fly the tracker in a test rocket this weekend.
You can set the two trackers to different frequencies, and then select between them using the selection wheel on the GPS page.

#### cabbey

##### Member
New advanced feature, extra low power consumption for lost rockets. After a tracker detects that it has been launched, if if loses contact with its ground station due to terrain in the way, such as after landing, it goes into a lost rocket mode. In lost rocket mode the tracker transmits on both the lost rocket channel (so other rockets will relay its data) and on its original channel that its ground station is listening to. I'm currently working on reducing the average power used in lost-rocket mode to extend the time available for recovery. I should be able to at least double the current lifetime for a given battery size while in lost rocket mode, and a factor of 10x may be possible. if it's double time, then a standard small 400 mAhr battery should be able to last for more than 10 hours.
Awesome to hear about these new developments! I can't wait to start playing with them. If I may make a suggestion here... an exponential back off might be an interesting idea to explore. Halve frequency of broadcasts after some amount of time, then halve them again after a block of time, then halve them again... etc. Maybe stop when you get out to some ridiculously long time between squaking... possibly make it user configurable what the slowest update frequency once the rocket is at rest will be? I know if I'm the only one at the club flying with your stuff I'd want a longer time than if there were dozens of others that could possibly see it while in the air. The longer it's been, the less likely that someone will be coming over the horizon *right now* looking for it. I'd even suggest powering down GPS once the tracker is "at rest" to save battery for broadcasting.

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