[Elecraft] K2 upgrade mods tactical planning [was:Re: Return of the prodigal daughter]

[Ron D'Eau Claire]

Ha! I avoided getting into the mods, Margaret! 

I'd build the basic K2 as you see in the book, see that it is working
properly, then add the mods one at a time while checking operation in
between. That way, if you do stumble, you'll see where and what you did much
more easily.

The filter flattening mod is a simple one that you'll love it especially if
you try to listen to SSB. There's a real 'tilt' to the original second
filter bandpass in the pre S/N 3000 design. That's the filter at the output
of the I.F. amp that is there just to clean up excess wideband noise, so
it's involved whether you have the SSB adapter or not. 

I would also recommend the AF gain control mod and the PLL and BFO
oscillator stability mods for a CW op. 

The new crystals are a good idea if you are including the SSB adapter. 

The oscillator stability mods really show up mostly on the higher-frequency
bands above 20 meters. On the lower bands, the drift in these oscillators
tend to cancel,  but on the bands above 20 they add due to the way the
mixing scheme works. That can produce excessive drift on the higher bands. 

I'd not hesitate to operate the K2 without the mods in any but the most
demanding service such as PSK31 and then only be really concerned on the
higher bands. 

The firmware upgrades have greatly improved the frequency readout accuracy
of the K2 and so having more stable oscillators helps you make use of that
improvement. 

If you're going to add the KPA100 for QRO operation, it's nice to install
the keying shaping mod as well, although the K2 needs no apologies without
it. And if you do that, you don't need the KIO2. The KIO2 is part of the
KPA100 100 watt upgrade option. 

But first, your K2 as it came will work FB. Use it and decide what you want
it to do for you, then choose the  additions and mods that fit!

So far, retirement isn't a visible stage of life for me either but I'm
having fun in the meantime. Bob Hope laid out the future as far as I can
see: when we reach 70 he says that us guys still chase women, but we'll only
chase 'em downhill. Then by age 80 he warns that even our birthday suits
will need ironing. 

Ron AC7AC