[Elecraft] K3 HABC mod & stop press: WHAT DATE?

[Ron D'Eau Claire]

It's a judgment call, Julian. I had not noticed any issues either even
though I use a wide bandwidth filter to scan the CW bands: exactly the
situation the mod was designed for. 

The mod delays activation of the AGC by relatively strong signals within the
first I.F. (roofing filter) passband that some noticed when using a wide
filter and listening to a fairly weak signal. When a strong signal appears
nearby, it might cause the AGC to act, reducing the gain wanted to hear the
weaker signal. 

This will happen most often when using a wide first I.F. filter, then using
the second I.F. selectivity to enhance a weak signal within the first I.F.
bandpass. 

I prefer to use a narrower first I.F. (roofing) filter and keep the other
signal out entirely. Still, in extreme situations, the second I.F. can be
sharper than the narrowest roofing filter. That's one key reason why the K3
has a second I.F.! I simply haven't noticed it yet. 

If you do decide to do them mod, it's an fairly easy project. Don't try to
save the SMDs you remove. Put on some safety glasses and cut right through
the epoxy bodies with sharp diagonal cutters, then clean off the pads with
your iron and some solder wick. Since the parts are *surface* mounted (no
leads through holes) it is  much easier to clean off the pads than it is
with the typical leaded parts. Then you add the new parts with the leads
laying on the solder pads and trim off the excess leads.  

Ron AC7AC


-----Original Message-----
With my limited skills I'm not going to risk carrying out this mod which
even the thru hole version involves removing an SMD component. If it wasn't
for this reflector I wouldn't even know anything was wrong, so why risk
damaging a working radio?

-----
Julian, G4ILO  K3 s/n: 222 K2 s/n: 392
G4ILO's Shack: www.g4ilo.com