# BRB900 major issue.

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#### Bat-mite

##### Rocketeer in MD
Sent this via e-mail to Greg of BRB, also.

My BRB900 stopped working at my last launch. It had a fresh battery charge (Tx and Rx). I put it in the rocket and put it on the pad. I got a good signal and coordinates.

It was a long time before they actually got around to launching my rocket. Meanwhile, I looked again at the receiver, and it had gone to all asterisks, with an S0 (for no satellites).

Since then, that is all that I can get out of it. When I turn on both units, the transmitter's LED flashes, then it goes dark. The receiver boots up, but shows all asterisks and S0.

Does this sound like a Tx problem or an Rx problem? I can't tell if the transmitter can't get a satellite, or if it has lost comms with the receiver.

Is it possible that the Tx battery drained during that 20 minutes or so on the pad after it had been fully charged?

Thanks for any help.

#### DavidMcCann

##### Well-Known Member
Is the LED on the Tx flashing?

mine will flash a bunch on boot up, ten goes black until it has a lock, then blinks once a second.

#### Bat-mite

##### Rocketeer in MD
It does flash when I plug in the battery, then goes dark and stays dark.

#### mccordmw

##### Well-Known Member
If the Tx powers and flashes and then stays dark.
If the Rx picks up a signal from the Tx, but just shows no satallites.

Then maybe the integrated ceramic patch antenna came loose?

#### Bat-mite

##### Rocketeer in MD
Do you know if that's easy to fix?

#### timbucktoo

##### Well-Known Member
Staff member
Global Mod
The patch antenna on mine came loose and i just resoldered it. It is the pin in center of GPS module that comes thru the board. Pretty easy.

#### Bat-mite

##### Rocketeer in MD
The patch antenna on mine came loose and i just resoldered it. It is the pin in center of GPS module that comes thru the board. Pretty easy.
I'll take a look, thanks!

#### Buckeye

##### Well-Known Member
TRF Supporter
As a fellow BRB900 owner, I am curious to hear what Greg had to say.

I also freak out when I see "S0", but that could also mean 10 satellites!

#### Bat-mite

##### Rocketeer in MD
As a fellow BRB900 owner, I am curious to hear what Greg had to say.

I also freak out when I see "S0", but that could also mean 10 satellites!
He said to send it in to him. I looked at the attena solder joint and it doesn't look bad to me. I'll let him give it a once-over.

#### cerving

##### Owner, Eggtimer Rocketry
TRF Supporter
Those patch antennas have a copper pin, if the antenna gets a good jolt typically the pin will break on the antenna side, not the PC board. It has to be removed, the broken pin needs to be unsoldered from the board, and a new patch antenna needs to be installed and resoldered. I've seen the same issue with the GPS module in the Eggfinder, and I would imagine that any GPS patch antenna using conductive adhesive for mounting would be susceptible to this problem. You can prevent it by putting heat-shrink over the GPS module, or a bead of epoxy around the edge of the antenna.

#### bigredbee

##### Well-Known Member
Yeah -- S0 with valid GPS data does really mean 10. Older GPS modules never got more than 9 sats locked, but that changed when I upgrade to u-blox. However, I never updated the receiver firmware. What's strange about the the description of this problem is the observation that it reverted to all asterisks. This should only happen if the transmitter got reset, otherwise it should continue to send the last known good position. As far as why it won't get a lock now, I'll report back here with what I find.

#### Bat-mite

##### Rocketeer in MD
I'll get it into the mail tomorrow!

#### Bat-mite

##### Rocketeer in MD
Word is that I had accidentally set the Tx to NMEA mode, and the Rx to NMEA mode. So the battery dies after 1.5 hours of use. Greg gave me a new battery and charged it and is shipping it back to me. My bad. Great product, great vendor, great customer service!

#### bigredbee

##### Well-Known Member
Some background. If you have it set to send the $BRBTX sentences, the firmware will aggregate the information from several NMEA sentences into one string (to include lat/lon/alt/hdop/vdop, etc) and send over the RF Link at the user specific rate (I usually set it to once every 5 seconds). If you set it to NMEA mode, the firmware will send *all* of the data (I think three or four NMEA sentences including$GPGGA and \$GPRMC) once every second. The end result is that you're sending at least 10x the data over the RF link, and the RF link is the biggest drain on the battery.