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Impedance matching in LNA

Submitted by Alexdobrianski  on February 25, 2013

Helical antenna 138 +0J, LNA matching with patch cable 50om X*Lambda + 0.04*Lambda -> 1.2pF + 3.3nH + strip 83om (w=0.33mm d=0.36mm) 21mm

Helical Antenna 138+0J, BT input/output 50+0J matching 3.3nH patch cable X*Lambda + 0.04*Lambda.

Both helical perfectly working on 1200m with 0dBm power (BT).

3 cascade LNA each with 3.3nH and capacitors 1.3 on input does 1200m not more.

3 cascade LNA each with 2.7nH->3.3nH->3.3nH and capacitors 1.3 on input does 100m not more.

3 cascade LNA each with 2.7nH and capacitors 1.3 on input does 50m.

3 cascade LNA each with 3.3nH -> 2.7nH -> 2.7nH and capacitors 1.3 on input does 100m not more.

But it allow to calculate diagram 10 degree  for 3 turns, and 2degree for 16 turns, angle in direction of a end of conductor wire, it is stupid – on a school’s football field that angle was missed. That make adjustment for a test over SFU. Angle has to be tried in direction of end of a wire.

Frustration == definitely, if for LNA will not be able to find solution – everything else does not make sense – communication will be not possible on a lunar distances. The same amplifier chip working perfectly on output, but 3 in cascade works like attenuator  reducing signal  instead of amplifying. Attempt to switch sides (on top  QE park cellular phone transmitters) did not help at all. Best suggestions to check signal with network analyzer and oscilloscope is out of reach for me. Thanks Boris for tip == needs to try connect both parts with attenuator 30dB (10k/9om) in that case it can be a brutal force = no need to go outside == all parts will be on table and soldering each of cascade for a best performance can be done faster.

Sorry no video today – even with 45min technical recording – some idiot virus crushed inventory website (chances ==2/365) , same time prime HDD crashed (chances == 1/3*365), same day change of a password  request change(chances==2/365) -> retype->wrong password(chances=1/3) ->computer locked till Monday (2/7) ,  same day system CD disk not readable at 9PM (chances 1/10) total probability to happened in one day is:  2*2*2/365*3*365*365*3*7*10 == 1 in 3 billion – Way! And it really happened! Definitely moon is easy!

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