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Here's the datasheet for a SAW filter that Erik was using:
? ??
On page 6, it shows that to make it work well in a 50 ohm environment,
both ports should have a series 33nH inductor attached to the part,
and then a 5.6pF cap to ground on the far side of each inductor.

You can't just connect two SAW filters together, you get much better results?
if you have the above matching network on both sides of both SAW filters.
? ??/g/HBTE/topic/69385413#675

So between the two SAW filters, you should have a 33nH inductor in series with one port,
then a 5.6pF cap to ground to drive a 50 ohm line between the two SAW filters,
then a 5.6pF cap to ground and another 33nH inductor into the other SAW filter port.
In Erik's notation, that would be an LCCL network, but if the 50 ohm line is short we can?
just combine the two C's into one big parallel C of 2*5.6=11.2pF:? ?LCL

As the calculations in post 674 note, we could get by with just a series 48.4nH inductor
between the two SAW filters, no caps.? So in Erik's notation:? ?L

But you have to buy the 33nH inductors and 5.6pF caps for the ends anyway, so may as well
get 10 of each and use them in the middle too.
So if each port has a series L and C to ground:? ? ?CL--SAW--LC-CL---SAW---LC

Erik's notation of CLC (ends) and CLCLC (in the middle) seems to be suggesting
the addition of caps to ground at each saw filter port, I doubt that is necessary.

The above values for L's and C's are for a B3550 SAW filter.
You need to consult the datasheet for the filter you wind up using to determine
the correct L and C values that will match it to 50 ohms.

Jerry, KE7ER?




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