Nate and I (Andrew) tuned the 2.422GHz and 1.277GHz helical antennas with Phillip Wong's help using the HP network analyzer in PSU's microwave lab.
Here's the results:
1.277GHz Helical Antennas
Antenna A:
- Used N->SMA cable "A" to test (cable "B" had a bad SMA connector - pin stuck up to far).
- VSWR = 1.33 and looked pretty flat across the frequency range. It was pretty robust to hand waving and torquing the antenna, which is good.
- Filename: 1277m_a
Antenna B:
- Used N->SMA cable "A" to test
- VSWR = 1.17 and looked pretty flat across the frequency range. Go Glenn go!
- Filename: 1277m_b
2.422GHz Helical Antennas
Antenna A:
- Used N->SMA cable "A" to test (cable "B" had a bad SMA connector - pin stuck up to far).
- VSWR = 3.03. We tuned it by trying solder blobs and finally picking the microstrip off the ground plane. This antenna was very twitchy and very sensitive to stuff in it's near field. The final microstrip tweaking gave a final VSWR = 2.00, but that was with the microstrip hanging off in the air (as Tim says, I "rediscovered the tapered microstrip").
- Filename: 2422m_a
Antenna B:
- Used N->SMA cable "A" to test (cable "B" had a bad SMA connector - pin stuck up to far).
- VSWR = 11.82. We left it alone since it was < 2. Again, tweaky to near field objects and which direction it was pointed.
- Filename: 2422m_b
Antenna C:
- Used N->SMA cable "A" to test (cable "B" had a bad SMA connector - pin stuck up to far).
- VSWR = 4.1. We lifted up the microstrip and tuned it to VSWR = 1.53.
- Filename: 2422m_c
Just to make sure our VSWR reading were right, we tried the calibrated 50ohm load again and got a value of 50.09ohms which is right.
2.422GHz Slot Antenna
We cut cable B's SMA cable off since it was weird and did a half-assed job of touching the network analyzer to the 2.422GHz slot in the airframe. We got a VSWR = 5.5 but we didn't expect much since we didn't have a matching balun or anything (including a good connection :).
Thanks to Phillip, who made this first test possible!
Attachments: