TeleMega/TeleDongle Communication - Range Issues

The Rocketry Forum

Help Support The Rocketry Forum:

kerolox22

New Member
Joined
Mar 4, 2019
Messages
1
Reaction score
0
Firstly, I apologize if this has been posted before, but I've been unable to find anything related to my issue. Shoot me a link if a thread exists.

I'm currently experimenting with a ground station that will be communicating to a TeleMega v3.0 on a rocket that will fly to approx. 30k ft. I am using the TeleDongle for the receiver with a 1/4 wave rubber-ducky antenna. Here's an Amazon link to the antenna.

I am able to successfully communicate between the two devices over RF over very short distances (say 5 feet or so), and the reported RSSI value in "Monitor Idle" is steady at about -60 dB or so. I setup the TeleDongle on a table with the antenna pointing upwards. As I hold the TeleMega and walk a short distance away (making sure that the TeleMega has a clear LoS to the TeleDongle) I quickly lose connection between the two devices at distances of about 15-20 ft, and the RSSI drops to about -85 or so before cutting out.

There's no break in the TeleMega's antenna (checked with multimeter), the battery voltage is about 4V with included LiPo, and everything seems to work fine until the distance is greater than 15 feet.

I wanted to post this here to see if any of you guys have had a similar issue before and if you've had luck resolving this problem. Any Ideas?
 

timbucktoo

Well-Known Member
Staff member
TRF Supporter
Global Mod
Joined
Jun 13, 2014
Messages
7,197
Reaction score
928
Location
Cocoa Beach
How is your telemega mounted? Or are you just holding the device?
 

DaveW6DPS

Well-Known Member
Joined
May 28, 2013
Messages
474
Reaction score
226
Location
Barstow, CA
Do you know anyone who has a Telemega system that could help you troubleshoot? It would help to at least isolate to transmitter or receiver, but if you only have one of each that can't be done.

You said you did a continuity check on the telemega antenna. How about on the teledongle antenna connector?

Not the greatest antenna, but unless it is defective it wouldn't cause this much of a drop out. You will get better range with a better antenna.

Have you visually inspected the telemega, and compared it to the photos on he Altus Metrum site? If one of the components that couples Tx power to the antenna was missing or open it could cause this. With surface mount capacitors there is is probably no way you can test them.

Do you have a radio receiver that will pick up the 70cm band? Listen on the Telemega's frequency. You should be able to hear the FSK bursts. If it is very weak, and drops off with short distance it would indicate that the telemega is the problem. If you can hear the signal and it will still break squelch on the receiver a couple of hundred feet away, then the problem is in the teledongle.

Can you configure the telemega over the radio link?

And just to make sure, are you sure the transmitter and receiver are on the same frequency? If they are set to different frequencies the strong signal within a few feet may get picked up, but drop off with distance. Unlikely, but possible.
 
Top