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RF attenuation due to battery interference problem - RF Cafe Forums
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mjmariveles
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Post subject: RF attenuation due to battery interference problem
Posted: Wed Nov 22, 2006 4:08 am
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Joined: Wed Nov 24, 2004
1:51 am Posts: 2 Location: Hongkong
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Hi All, I have problem with my 315Mhz SAW
based transmitter if the battery is mounted at the
backside underneath of the transmitter circuit.
It's transmission power will attenuated at large
size around -2dBm down to -40dBm. Do you
have any experience on this problem? You know it's
quite headache, since I been using many types of
battery sheilding material and ferrite beads, filters
caps...still doesn't work! Anybody there
please help..thanks!
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karthik |
Post subject:
Posted: Wed Nov 22, 2006 9:05 am
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Joined: Tue Apr 11, 2006
8:13 pm Posts: 34 |
Could the battery be heating the SAW and causing
a frequency drift? How big is the bandwidth?
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karthik |
Post subject:
Posted: Wed Nov 22, 2006 9:06 am
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Joined: Tue Apr 11, 2006
8:13 pm Posts: 34 |
You could quickly cross check the frequency drift
due to temperature by operating the transmitter
without mounting the battery on the same chassis
as the transmitter
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mjmariveles |
Post subject: pcb antenna trace
Posted: Thu Nov 23, 2006 1:48 am
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Joined: Wed Nov 24, 2004
1:51 am Posts: 2 Location: Hongkong
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thank you! i found the problem and was caused
by de-tuning the antenna since its very close beneath
when a coin battery is mounted. am using a fixed
wire type awg#30 monopole antenna. by the
way, i would like to change the antenna to a pcb
loop trace type. do you any information about this
on how to design? please help. thank you!
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Posted 11/12/2012
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