Filter board

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Ulf (SM0NOR)

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Jun 8, 2021, 11:19:25 AM6/8/21
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Hi,
I'm building all three boards as an educational journey into SSPA. Otherwise, I'm a seasoned tube-guy..
About the filter board; there is no clear indication from what direction to populate the filter components. I'm assuming 6M should be closest to the in/out posts, i.e. C1A-B-C and L1A-B? But, what confuses me a bit, is that on the band pin header, its is pin no. 6 that goes the that filter. Logic tells me it should be pin no. 1. Therefore I'm confused :-)
Thanks for any input..
SM0NOR - Ulf

jcve...@gmail.com

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Jun 8, 2021, 11:58:17 AM6/8/21
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Hi Ulf,

You are correct, it is best to put the highest frequency filters closest to the connectors. The EA2-12 relays have good RF characteristics but putting the high frequency signals through as few as possible makes the most sense.

I guess that my logic went in frequency, not filter bands so if you have your filters set up like this

Filter 1 - 6M
Filter 2 - 10/12/15M
Filter 3 - 17/20M
Filter 4 - 30/40M
Filter 5 - 60M
Filter 6 - 80M
Filter 7 - 160M

Then the Band header control signals should be:

No pins grounded - 160M
Ground pin 1 - 80M
Ground pin 2 - 80M
Ground pin 3 - 30/40M
Ground pin 4 - 17/20M
Ground pin 5 - 10/12/15M
Ground pin 6 - 6M

There is a chart on the website that shows the BCD band coding if you don't want to use a line for every filter.

73,
Jim WA2EUJ


Ulf (SM0NOR)

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Jun 8, 2021, 3:38:04 PM6/8/21
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Thanks a lot!
The build continues :)
Ulf - SM0NOR

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