I haven't ever experienced a problem with strong on-channel overload with the K3. But it's possible that you're hitting it with so much power that you're putting one or more RX stages into saturation, possibly including the I.F. amp. (In an extreme case, you could even be exceeding the useful range of the TR switch PIN diodes. The FT817, if I'm not mistaken, uses a TR relay.)
While it's perfectly reasonable to expect the operator to turn on the attenuator in such a situation, there may be a way to modify the K3 to handle these signals, depending on where the saturation is occurring. As an experiment, I would try adding back-to-back silicon diodes (1N4148 or 1N914) at the output of the crystal filter and/or at the output of the IF amp. The question is where to add them. One possibility is across the primary of T5 in the IF amp, which would drastically limit the max p-p voltage obtainable from this stage. Another, less-invasive possibility would be across L39. At any normal signal level the diodes would be essentially out of the circuit. On large signals, they'd clamp the voltage at this point to about 1.4 Vpp. 73, Wayne N6KR --- http://www.elecraft.com ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
