Hi all,
I have a question re L2 on the 2m lpf.
All other lpf's have the value of L2 higher than L1,L3, in the 2m lpf page Tor, SM6FWF states that his L2 is a smaller value than L1,L3 but does not give values, should L2 for 2m be higher than L1,L3?
I think it should be higher.
Andy
--
The universe is made up of Protons, Neutrons, Electrons but contains only one M0RON.

开云体育

Andy,

You could try modelling the filter on the Elsie program, free for students. To calculate the inductance of the coils, use mini ring core calculator by DL5SWB. Bit long in the tooth now but it still gives a good answer.

These two programs can give quick results and the values can be adjusted to get the response you like.

Geoff

You will find the answer you seek, on the lo pass filter page, on Hans' site.
Good luck.
Trevor

Hi Trevor,?
No that is what I queried. On that page it says that L2 is made longer than the other two inductors for a lower inductance value, but, all other filters have L2 at a higher value.?
I was inclined to make it shorter or an extra turn, 4 turns, to give a higher value, Geoff's suggestion to try Elsie bears this out, anyway I wound 3 turns on a 6mm drill and squeezed L2 slightly shorter than happy other two,?
I think I made L1 and 2 7.4mm long and L2 6.6mm long.?
Andy
--
The universe is made up of Protons, Neutrons, Electrons but contains only one M0RON.