[TenTec] Receivability

[George, W5YR]

Caity, a question, out of curiosity:

Historically, "single-signal reception" has always meant sufficient
selectivity that the operator could not hear "the other side of zero beat."
This was first achieved in the 1930's with Jim Lamb's revolutionary crystal
filter - which used a single crystal, BTW.

Is this what you are referring to? Or do you want to be able to hear only
the "single (no hyphen) signal" that you are working or listening to, all
others being excluded?

If the former, I have found that filter bandwidth has little to do with
"the other side." Any good filter should have adequate rejection for that
task almost without regard to its passband width.  The shape factor has
more to do with that than the bandwidth, and the chief player, of course,
is the location of the BFO injection frequency relative to the passband.

Where this all falls apart is when an op wants to copy a low beatnote and
yet use a fairly wide filter. I once had a fellow complain that his new
Icom 756PRO was defective because when set for a 450 Hz offset and 800 Hz
bandwidth, he could hear QRM from "the other side." No amount of
explanation could convince him that such a setup was doomed from the start
. . .

If the latter, then I can appreciate your desire to use the narrowest
possible filter. I frequently use 50 and 100 Hz IF DSP filters on my PRO
when the going gets really rough!  <:}

73/72, George    
Amateur Radio W5YR -  the Yellow Rose of Texas
In the 57th year and it just keeps getting better!
Fairview, TX 30 mi NE of Dallas in Collin county EM13qe
K2 #489      Icom IC-765 #2349     Icom IC-756 PRO  #2121


Caitlyn Martin wrote:

> I have always found CW a chore, and even more so now that my code speed
> is up to a respectable level.  I want single signal reception, which, to
> me, means the narrowest filter possible without ringing.  My main
> objection to the Scout on CW is that the Jones filter can't go narrow
> enough for my ears.  The Argosy with the optional filters is *much*
> better.  I know some of you serious CW ops have wonderful filters in
> your heads.  Mine is defective :)