[CW] 600 Hz Resonant Speaker for CW - Plans

[Jeffrey Herman]

Not a "reader" -- I'd like the "tutor". It sends random Morse. Ideal for long morning and afternoon commutes and on board an airplane.


Jeff KH6O




----- Original Message -----
From: Sergio R Rubio <srrkp4l at onelinkpr.net>
Date: Wednesday, September 2, 2009 5:38 am
Subject: Re: [CW] 600 Hz Resonant Speaker for CW - Plans
To: CW Reflector <cw at mailman.qth.net>

> I have a Morse Code Reader MFJ-461, with its 9-volt battery 
> included and 
> working OK, for sale. Please let me know.
> 
> Sergio KP4L
> No. 1 Honor Roll
> FOC 1090
> ----- Original Message ----- 
> From: "Jeffrey Herman" <jeffreyh at hawaii.edu>
> To: <flymooney at gmail.com>; "CW Reflector" <cw at mailman.qth.net>
> Sent: Tuesday, September 01, 2009 7:17 PM
> Subject: Re: [CW] 600 Hz Resonant Speaker for CW - Plans
> 
> 
> > Great. Well, if it was an April Fools article, I fell for it.
> >
> > 73, Jeff KH6O
> >
> > PS: If anyone has an MFJ Morse Tutor you'd like to sell, 
> please let me
> > know.
> >
> >
> >
> > On Tue, 1 Sep 2009, Patrick wrote:
> >
> >> Jeffrey Herman wrote:
> >> >  I seem to recall an article about a VERY narrow CW 
> mechanical filter,
> >> > constructed as such: Take a pair of old headphone "cans", 
> remove the
> >> > outer plastic ear cover, then remove the metal diaphram. 
> Using a metal
> >> > cutter called a nipper (?), trim the diaphram in such a way 
> that, for
> >> > the most part, just a reed appears in the center (the 
> longer the reed,
> >> > the lower its resonant frequency, and vice versa). Replace 
> the diaphram
> >> > and cover. Now that particular earpiece will only pass 
> signals whose
> >> > audio freq'y exactly matches the reed's resonant freq'y.
> >> >
> >> > One of those "ah-ha" type of simple but effective projects.
> >> >
> >> > 73, Jeff  KH6O
> >>
> >> This was from an article in the April 1976 QST. I think this was
> >> something for the April Fools issue as the author's name was "Tinh
> >> Ehres" (Tin Ears) with a call of WH0OP. I remember reading 
> about it
> >> before I was a ham (an Elmer had given me a bunch of old 
> QST's) back in
> >> the early 80's. I have the .pdf of it or if you are a member 
> of the
> >> ARRL, you can do an article search. The title is "CW Super-
> Selectivity".>>
> >> Patrick KA4ZNU
> >>
> >>
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