[CW] 600 Hz Resonant Speaker for CW - Plans

[Sergio R Rubio]

For your information, MFJ has been making code readers for several years. 
Check latest
MFJ catalog, page 29, and you will see it by yourself: "MFJ Pocket size 
Morse Code
Reader TM"  This is the one I am selling; if you are interested, just let me 
know.

Sergio, KP4L
----- Original Message ----- 
From: "DANNY DOUGLAS" <N7DC at COMCAST.NET>
To: "CW Reflector" <cw at mailman.qth.net>
Sent: Wednesday, September 02, 2009 11:47 AM
Subject: Re: [CW] 600 Hz Resonant Speaker for CW - Plans


> Is that another April Fools joke?  A machine to read
> Morse code???
>
>  I tore apart 3 headphones, trying to build a mechanical audio
> filter, and never could get them right, since my left and right ears have
> different hearing losses.
>
> HI
> Danny Douglas
> N7DC
> ex WN5QMX ET2US WA5UKR ET3USA
> SV0WPP VS6DD N7DC/YV5 G5CTB
>
> All 2 years or more (except Novice)
> Pls QSL direct, buro, or LOTW preferred,
> I Do not use, but as a courtesy do upload to eQSL for
> those who do.
>
> Moderator
> DXandTALK
> http://groups.yahoo.com/group/DXandTalk
> DXandTALK at YAHOOGROUPS.COM
>
> Moderator
> Digital_modes
> http://groups.yahoo.com/group/digital_modes/?yguid=341090159
>
> ----- Original Message ----- 
> From: "Sergio R Rubio" <srrkp4l at onelinkpr.net>
> To: "CW Reflector" <cw at mailman.qth.net>
> Sent: Wednesday, September 02, 2009 11:38 AM
> Subject: Re: [CW] 600 Hz Resonant Speaker for CW - Plans
>
>
>>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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>>
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>
> ______________________________________________________________
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