TYT manufacturing defect on GPS antenna. UV380/RT3S

[ve2wkr]

Hello!,
I have 2 TYT radios , MD-UV380 and RT3S, they are identical except for the front brand name label. I found that the GPS sensitivity was awful, and it would easily loose GPS tracking in a wooded forest.
On the RT3S is did the GPS mod described on this board to install the antenna at the top of tha radio. It was quite a bit of work , but it does work very well.
While taking apart the original TYT GPS antenna I noticed that it is installed with sticky tape, and only one lead is soldered to the board.
This should not be the case, and both the signal, and ground antenna lead should make contact with the board.
So, on my second radio the MD-UV380 I decided to remove the original GPS antenna, clean the sticky tape off, apply some solder to the board, and re-install it.

IMG_20230822_130417_386.jpg (46.87 KiB) Viewed 1633 times

After cleaning the back of the antenna with alcohol I held the antenna in place with alligator clips while soldering it back.in place.
As I expected this made a big difference, and now both radios have about the same GPS sensitivity.

IMG_20230822_125331_643.jpg (43.88 KiB) Viewed 1633 times

why would TYT engineers think sticky tape makes a good electrical connection ???

here the TYT radio has the original antenna properly installed , while the Retevis has the antenna at the top as per mod on this board.

IMG_20230822_133218_639.jpg (49.08 KiB) Viewed 1633 times

The above picture is inside a house.The GPS acquisition time is about the same for both radios. There is a slight signal difference as one antenna points forward while the other points up, however it does not change the overall sensitivity of the GPS receiver.
Note that heating the back of the antenna results in holes in the ground plane as it is just solder. Hence the best way to have the antenna ground plane make a connection with the radio ground is by contact and alligator clips to hold the antenna in place while soldering the signal pin back.
73's
Luca

[CU7AAZ]

Hello!,
I have 2 TYT radios , MD-UV380 and RT3S, they are identical except for the front brand name label. I found that the GPS sensitivity was awful, and it would easily loose GPS tracking in a wooded forest.
On the RT3S is did the GPS mod described on this board to install the antenna at the top of tha radio. It was quite a bit of work , but it does work very well.
While taking apart the original TYT GPS antenna I noticed that it is installed with sticky tape, and only one lead is soldered to the board.
This should not be the case, and both the signal, and ground antenna lead should make contact with the board.
So, on my second radio the MD-UV380 I decided to remove the original GPS antenna, clean the sticky tape off, apply some solder to the board, and re-install it.
IMG_20230822_130417_386.jpg
After cleaning the back of the antenna with alcohol I held the antenna in place with alligator clips while soldering it back.in place.
As I expected this made a big difference, and now both radios have about the same GPS sensitivity.
IMG_20230822_125331_643.jpg
why would TYT engineers think sticky tape makes a good electrical connection ???

here the TYT radio has the original antenna properly installed , while the Retevis has the antenna at the top as per mod on this board.
IMG_20230822_133218_639.jpg

The above picture is inside a house.The GPS acquisition time is about the same for both radios. There is a slight signal difference as one antenna points forward while the other points up, however it does not change the overall sensitivity of the GPS receiver.
Note that heating the back of the antenna results in holes in the ground plane as it is just solder. Hence the best way to have the antenna ground plane make a connection with the radio ground is by contact and alligator clips to hold the antenna in place while soldering the signal pin back.
73's
Luca

Hi,
There are other solutions in this topic, take a look

viewtopic.php?f=19&t=2415

73s
CU7AAZ

[ve2wkr]

Yes I have installed that antenna in one of my rt3s radios, but just fixing the original antenna is easier , and a lot less grinding ...
73's

EDIT:
I tested three RT3S/MDUV380 GPS , one with the original antenna, one with the original antenna , but with the fix above (ground connected), and one with the new antenna placed at the top as per thread in this forum.
Original Antenna: In a forest it would loose GPS tracking, and would not acquire the position again until I exited the forest. Sometimes it also never gets enough GPS satellites as I am in a valley.
Original Antenna with ground fix: I a forest it maintained tracking with 5 to 9 satellites no problems. Also work inside a home with wooden roof.
Top placed antenna mod: In a forest it had excellent signal with 10-12 satellites no problems. Also work inside a home with wooden roof, but will get 1-3 additional satellites.