>
>Ford Peterson wrote:
>>
>> I bought an SB-1000 from an estate that looks to be unmodified in any way.
>> Are there mods out there that I should investigate? Any on-line resources I
>> should look at?
>
>The stock plate RF choke may have a resonance near 17 meters. I replaced the
>one in mine with an Ameritron AL80B choke, which works well on all bands,
>including WARC. Cost about $25 from Ameritron.
>
>There is a very high potential gradient at the fixed bandswitch contact that
>grounds the 160-meter padder capacitor. This can actually cause a corona
>discharge from sharp points on the contact and the wire connected to it.
? To see what's happening, loosely couple a spectrum analyzer to the
anode. SB-1000/AL-80s are marginally stable. They tend to oscillate
intermittently at 155MHz. Lower VHF Q suppressors are needed to reduce
parasitic arcing. See my website for photos of burned bandswtiches. .
later, Vic
- Rich..., 805.386.3734, www.vcnet.com/measures.
end
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