[AMRadio] Dreaded D-104

Thu Oct 6 11:15:49 EDT 2011

What Bob (the N0DGN one) just posted is probably the simplest least complex way 
to do it. Just for scientific rigor, that method does lump in the nonlinear 
frequency responses of the speaker which over the voice frequency range probably 
won't make any difference whatsoever not to mention the fact that we're 
discussing D-104's. I have two......one with the Heil cartridge and one stock 
both less that pos preamp that Astatic saw fit to include I guess for the CB 
crowd.

A lab would use a Pink Noise generator, a calibrated amp and speaker and a 
plotter. I'm probably preaching to the choir, but White Noise has equal energy 
per Hz. which gives it a nonlinear frequency response rising with frequency. 
 Pink Noise is filtered White Noise which has equal energy per octave i.e. a 
flat frequency response. 

Pink Noise has nothing to do with the verbosity thrown out at a Mary Kay 
convention.

________________________________
From: Bob Macklin <macklinbob at gmail.com>
To: Jack Dayton <ka3zlr1 at yahoo.com>; Discussion of AM Radio in the Amateur 
Service <amradio at mailman.qth.net>
Sent: Thu, October 6, 2011 9:18:20 AM
Subject: Re: [AMRadio] Dreaded D-104

I'm just curious?

Does anyone know how to measure the characteristics of a microphone. I don't 
suspect many (if any ) hams have what it takes to measure the 
characteristics of a microphone.

Most of the measurements hams could do would be subjective.

Bob Macklin
K5MYJ
Seattle, Wa.
"Real Radios Glow In The Dark"

----- Original Message ----- 
From: "Jack Dayton" <ka3zlr1 at yahoo.com>
To: "Discussion of AM Radio in the Amateur Service" 
<amradio at mailman.qth.net>
Sent: Thursday, October 06, 2011 4:57 AM
Subject: Re: [AMRadio] Dreaded D-104

You can say that Rob but all elements are not equal each has it's own

distinctive personality.Through the years I have amassed a collection
of heads and spent a great deal of time with the Scope going through
them I noticed some interesting responses. One of the reasons I pulled
the element out replaced it. the HC5 does a much finer job.

73
Jack
KA3ZLR

________________________________
From: Rob Atkinson <ranchorobbo at gmail.com>
To: Discussion of AM Radio in the Amateur Service <amradio at mailman.qth.net>
Sent: Wednesday, October 5, 2011 11:29 PM
Subject: Re: [AMRadio] Dreaded D-104

they probably sound "tinny" when they are mismatched for the rig's
audio input stage.

My recommendation is go to hamfests looking for D104s.  But not any
one. ignore the ones with coiled cords, preamps in the base, gold
leaf, "special editions," and "eagles" and look for the oldest
crustiest ones you can find. They are pretty easy to take apart and
clean up. If they lack PTT that's even better.  At the Indianapolis
Hamfest last summer there must have been at least 30 of them for sale.
It seemed every other table had at least one; many had half a dozen.
If you find an old one it might go for 20 bucks. That's probably your
best bet for finding a ceramic old Astatic high Z element. Obviously
you'll have to buy more than one unless you get lucky.
That's the only way I know of. I tried buying a vintage 10 meg xtal
element tape recorder mic and doing a transplant but you get into
issues trying to get a non-D104 element to fit and it usually doesn't
work out. I wound up breaking the cartridge I had trying to get it to
fit.

Rob
K5UJ
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