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We got a copy of the hardware and took a first crack using a lowpass Chebyshev filter at 950MHz (radio transmits up to ~930MHz). On the first pass, we got a .2dBm drop on the fundamental [margin o...
Answer
#3: Post edited
by
leroy105
·
2021-03-31T17:01:11Z (over 3 years ago)
- We got a copy of the hardware and took a first crack using a lowpass Chebyshev filter at 950MHz (radio transmits up to ~930MHz).
- On the first pass, we got a .2dBm drop on the fundamental [margin of error in our test chamber] and a 12db drop on the most severe harmonic.
- I don't know if the Chebyshev cutoff at 930MHz vs. 950MHz, is going to have a huge impact on harmonics coming off the system 3GHz+. I'm not going to investigate further since we got such a great and easy result on the first pass.
- Because we don't have any issues with other harmonics of the system, until like the 7th harmonic or so, a low pass filter totally worked here.
- I didn't layout the board, but I'm super glad the layout guy decided to add in an additional PI network for future filtering.
- I've impedance matched a few RF systems using a VNA, and if you have the space, those extra three components are life savers.
I've always gotten rock star results (way above FCC limits) tuning up our system.
- We got a copy of the hardware and took a first crack using a lowpass Chebyshev filter at 950MHz (radio transmits up to ~930MHz).
- On the first pass, we got a .2dBm drop on the fundamental [margin of error in our test chamber] and a 12db drop on the most severe harmonic.
- I don't know if the Chebyshev cutoff at 930MHz vs. 950MHz, is going to have a huge impact on harmonics coming off the system 3GHz+. I'm not going to investigate further since we got such a great and easy result on the first pass.
- Because we don't have any issues with other harmonics of the system, until like the 7th harmonic or so, a low pass filter totally worked here.
- I didn't layout the board, but I'm super glad the layout guy decided to add in an additional PI network for future filtering.
- I've impedance matched a few RF systems using a VNA, and if you have the space, those extra three components are life savers.
- I've always gotten rock star results (way above FCC limits) after tuning up our systems.
#2: Post edited
by
leroy105
·
2021-03-30T21:29:17Z (over 3 years ago)
- We got a copy of the hardware and took a first crack using a lowpass Chebyshev filter at 950MHz (radio transmits up to ~930MHz).
- On the first pass, we got a .2dBm drop on the fundamental [margin of error in our test chamber] and a 12db drop on the most severe harmonic.
Because we don't have any issues with other harmonics of the system, until like the 7th harmonic or so, a low pass filter totally worked here.
- We got a copy of the hardware and took a first crack using a lowpass Chebyshev filter at 950MHz (radio transmits up to ~930MHz).
- On the first pass, we got a .2dBm drop on the fundamental [margin of error in our test chamber] and a 12db drop on the most severe harmonic.
- I don't know if the Chebyshev cutoff at 930MHz vs. 950MHz, is going to have a huge impact on harmonics coming off the system 3GHz+. I'm not going to investigate further since we got such a great and easy result on the first pass.
- Because we don't have any issues with other harmonics of the system, until like the 7th harmonic or so, a low pass filter totally worked here.
- I didn't layout the board, but I'm super glad the layout guy decided to add in an additional PI network for future filtering.
- I've impedance matched a few RF systems using a VNA, and if you have the space, those extra three components are life savers.
- I've always gotten rock star results (way above FCC limits) tuning up our system.
#1: Initial revision
by
leroy105
·
2021-03-30T21:26:22Z (over 3 years ago)
We got a copy of the hardware and took a first crack using a lowpass Chebyshev filter at 950MHz (radio transmits up to ~930MHz). On the first pass, we got a .2dBm drop on the fundamental [margin of error in our test chamber] and a 12db drop on the most severe harmonic. Because we don't have any issues with other harmonics of the system, until like the 7th harmonic or so, a low pass filter totally worked here.