[amsat-bb] Re: SSB SP-7000 rejection

Anthony Monteiro aa2tx at comcast.net
Sat Oct 4 19:32:53 PDT 2008

At 05:37 AM 10/4/2008, Tim Tapio wrote:
>Hello all,
>I'm planning a new antenna system and planning on using an SSB preamp on the
>430 downlink side. The 7000 uses helical bandfiltering.
>My antenna separation will be on an 8' fiberglas boom. Will desense be an
>issues? Should I plan on using a bandpass filter such as a duplexer?
>Thanks and 73 de Tim, K4SHF

Hi Tim,

The SP-7000 has a pair of back-to-back diodes on the input to
protect the gasfet BEFORE the helical filter so it is pretty easy
to overload it. I would guess that 8' is not enough seperation and
you will need the duplexor so you should probably plan for it.

Tony AA2TX

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