BRB

[bigredbee]

The problem is, unlike commonly used configs to track vehicles that tend to transmit "randomly", most people set up their transmitters to transmit at 5 second intervals. So, even if you have 5 transmitters set up to transmit on 5 unique timeslots, you'll run out of bandwidth when you add the 6th transmitter. It will work, you just have to coordinate very carefully.

They do this at the ARLISS launches to track the student projects.

Greg

 

[Fdog]

Dang. Hadn't thought of the density of transmissions we use in rocketry... the radios we use for APRS when off-roading "listen" before transmitting, and delay the Tx if another radio starts transmitting it's packet. Also, they look at the GPS positions, and change the interval according to how fast the radio is moving - if stationary, the interval is ~20 minutes, when moving quickly, at a rate you can program (~30 seconds or less).


All the best, James

 

[V2rocketeer]

Hi Greg

Thanks for the reply. I was going to email you directly and ask but I'll keep the thread going unless there is jeopardy of a hijack. If I understand correctly that The BRB syncronises with the GPS time stamp we are limited to 5 GPS running at one time if configured correctly? I was going to go so far as stating that only one APRS/BRB rocket would be allowed in the air at time. Those on the ground down range should not be a problem with the attenuation of being on the ground as strong as it gets. The issue would be having multiple rockets on the pads or in the pits armed and signalling. I would imagine that the trackers cannot be turned on until in a certain place heading out to or at the pads? I can just see a lot of benefits to having an APRS network going if one rx or another doesn't hear the last couple of packets but another does, especially a base station with an antenna on a mast.

73

vk2icj aka Chris

The problem is, unlike commonly used configs to track vehicles that tend to transmit "randomly", most people set up their transmitters to transmit at 5 second intervals. So, even if you have 5 transmitters set up to transmit on 5 unique timeslots, you'll run out of bandwidth when you add the 6th transmitter. It will work, you just have to coordinate very carefully.

They do this at the ARLISS launches to track the student projects.

Greg

 

[lmt56]

It has taken me awhile but I got to the point where I could run two receiving setups.
A base station and a mobile setup. Best of both worlds.
Key for me was getting access to a second Kenwood which is a major cost. Other than that no major cost to run a second unit.
My base station antenna is a Diamond X-30 and goes up on a cheap Harbor Freight flag pole.
Sure is nice to be able to leave the base station, letting it do its thing, drive to an away cell, and have a second receiver set up with a yagi.