[HBR] RE: Empirical Filters

[Don]

Walt,

Actually, building a ladder filter empirically just like you said will
often result in a good filter. A starting point for capacitors is mall
coupling caps for wide bandwidth, large for narrow. 

The web offers some simple crystal jigs to fine tune the process. In
fact, speaking of Mr Arland, I think the American QRP club offers a kit
that will assist in the crystal measurement process. Might be the New
Jersy QRP Club?

One question Walt? Where did you order your crystals from? I bet someone
else is curious like me? International Crystal is about 10 miles from
me. I have left an arm and a leg there before! Funny thing about the
back customer service office at ICM. They have this big box full of
thousands of crystals sitting in front of one of the desks. Must be
either rejects or discontinued types. I need to ask them what they do
with these. I suspect that ICM's days are numbered. They have moved from
a large building into a very small one to cut costs I suspect.

A thread on another site discussed the cost of parts to build tube
receivers. It is getting harder to find quality vintage parts to
reconstruct a 50's design which is the aim of many tube builders. Darned
if a good chassis doesn't scare you off if you are mechanically
challenged like me and can't use a metal bender to make one.

I personally think it is worth the effort to build a good tube receiver
at least once regardless of the cost. While my solid state transceivers
are fun, my tube station gets used more. About 2,000 hours so far. There
is something about tubes. Maybe the glow, maybe the history, certainly
the warm sound, that makes it worth the effort. I don't think anything
will teach you real radio like building a tube receiver. Or cause you to
get more e-mails asking questions.

Trouble is that there are not enough resources around like Walt, Kee's
and a few others carrying the torch.or should I say glowbug? Some fellas
will talk about their projects but Walt always tells about the good and
the bad results. How many people still build them let alone work up new
tube designs? Knowing what doesn't work is just as important as knowing
what does.

Trully excellent work Walt but we need to see pictures. Again, good luck
my friends on all your projects.

dk