[Elecraft] K2 Microphone -- what is it?

Wed Jan 15 23:05:00 2003

Hugh
It appears that along with sausage and legislation,
microphones are another thing you don't want to see
being made :-)
73, Bob N6WG

-----Original Message-----
From: [email protected]
[mailto:[email protected]]On Behalf Of [email protected]
Sent: Wednesday, January 15, 2003 12:17 PM
To: [email protected]
Cc: [email protected]
Subject: [Elecraft] K2 Microphone -- what is it?

I first built my K2, #2378, with KNB2, KAF, KAF2 and KAT2 and 
was as happy with the quality of the kit, the support and the 
resulting radio as anyone could be. I heartily agree with all 
the praise for Elecraft, its crew and its products.

Next I ordered the KIO2, K160RX and KSB2 modules. To be sure 
of good audio I also ordered the MH2 microphone with 
its "optimized Heil element". Again complete satisfaction.

However I am addictively curious, so I undid the three screws 
that held the MH2 together, for a peek inside. I was 
surprised. The curly lead came in with three (red, black and 
yellow) wires and a screen. Screen and black are connected 
somewhere in the lead. There is a double pole push switch. 
One half is PTT, connected to black and red. the yellow lead 
goes via the other pole to the microphome element, just 
behind the grille, and returning to the screen of the cable. 
This element looks just like the electrets I buy locally for 
one pound sterling ($1.30) or so. Presumably the MH2 has 
qualities they don't. The element was held in place by a 
square piece of pink plastic foam in a round hole. Being used 
to the quality and finish of all other Elecraft components, 
it was the cheap look of this foam not matching its hole that 
was my first surprise.

My other real surprise was to find another "object" looking 
as though it could be a microphone element behind another 
part of the grille, but not connected to anything. This 
object is cylindrical, about three quarters of an inch 
diameter and half an inch long. It is strongly magnetic at 
one end, and has an internal coil visible, connected to 
solder pads on a small piece of p.c.b. on its outside. These 
pads are connected to two more soldered pads which have marks 
where something has been cut off. By contrast with the pink 
foam, this object was held in place by beautifully moulded 
black foam neatly fitting it and its socket in the casing.

One disappointment was that the mic. had been assembled with 
the wires trapped between the case halves, so their 
insulation had been squeezed off. I re-routed the wires and 
re-assembled the mic. and was glad to find that it still 
fuctioned correctly, and perfectly satifactorily.

There is a small white label inside the case with the 
legend "09A01".

So, my questions are: Are all MH2s like this? What is the 
second "object"; What is the "optimization" that is done; 
and, dare I have the thought, Have I paid $58 for just an 
electret capsule in a fancy case with a curly lead and plug?

I would like to thank Elecraft for the wonderful kits they 
supply and all the support they give, and the folks who make 
this reflector such a useful and entertaining read. I 
download the digest once a week and read it at leisure, so I 
may not be able to reply to any comments on this for a few 
days.

Hugh M0SOP  IARU location IO90PS
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