[Heathkit] SB-104A large signal capability modification

[Ulrich Graf]

Hello to the list,

there is still quite a number of SB-104s around, even in Europe.
Unfortunately this transceiver has a receiver part that suffers
heavily from large signal problems like second and third order
intermodulation distortion. Due to extremely strong BCers in Europe I
detected such distortion pruducts in my refurbished SB-104 up to
levels of S 9+ 20 dB. With the intend to modify the rig as far as
necessary to be able to work even in the evening hours but not to an
extend that almost the complete circuitry would be involved I modified
those parts that contributed most to intermod effects.

All those mods are described in detail on my website:
www.mydarc.de/dk4sx. See chapter "Restauration" and scroll down to the
SB-104. Website is in German, but SB-104 mods are written in English,
too.

If you have any further questions, just email me: dk4sx at darc.de

vy 73,

Uli, DK4SX