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Hi AP2RF and Andy,

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#1

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Here is an explanation of how to calculate the values

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Andy is the expert here, (Andy please let us know how to decide on the factor if it should be 5, 10 or something else) but

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The way to calculate this is as follows you choose a factor (Andy appears to have chosen 5)

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For the series LC branch, XL should be equal to XC such that it needs to be [50 ohm (design impedance) x the factor]

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So 50 x 5 = 250 ohm reactive

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So XL = 2 x pi x f x L

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XC = 1/ (2 x pi x f x C)

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Both should equal 250 ohm reactive, see sample calculation of XL below for the series branch.

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So L = 3584.6 nH? XL = 250 ohm

?? C = 57.4 pf??? XC = 250 ohm

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For the parallel LC branch, the impedance should be XL = XC = 50/factor = 50/5 = 10 ohm

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We get

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C = 1433.8 pf ??XC = 10 ohm

L = 143.4 nH ???XL = 10 ohm

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Andy has already added a caveat here that availability of components dictated his design choices. (in the pdf)

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We get identical results from this online calculator see below ()

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#2

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With reference to your question for an IF of 9 MHz, see results below for the diplexer values,

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#3

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With reference to your amplifier question, I believe all the transistors you list are obsolete. However I have a stock of 2n5109s and use the amplifier from here, works really well.

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See the mixer section,

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See the broadband amplifier,

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See another broadband amplifier using the 2SC5551A (this is also obsolete)

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Vendor for the NE46134 (last 3 remaining)

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Another link for the 2N5109

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Kind regards