[Elecraft] My KX3 desk microphone project

[Walter Underwood]

I can’t imagine that paralleling four elements would make a big difference. It would be more directional at higher frequencies. A 2x2 array would be about 20mm across, which is one wavelength at 17000Hz. That would start to be directional, because angled waves would cancel out.

wunder
K6WRU
CM87wj
http://observer.wunderwood.org/

On Jan 23, 2015, at 4:50 PM, Gary - NC3Z <nc3z.gary at gmail.com> wrote:

> Provides more gain and improves the SNR.
> 
> Gary Mitchelson
> NC3Z Davidsonville, MD FM18
> NC3Z/4 Pamlico County, NC FM15
> www.mitchelson.org
> 
> On 1/23/2015 7:33 PM, Gary K9GS wrote:
>> 
>>> Just curious...what is the point of paralleling 4 microphone elements?
>>> 
>>> On 1/22/2015 10:44 AM, Gary - NC3Z wrote:
>>>> I wanted a desk mic to go along with my KX3 station. Wanted something more portable than the Heil boom and mic I use on my other radio. I have experimented with dynamic mics on the KX3 and didn't get the results I liked but did get very nice results with using 4 CUI electret condenser mic elements in parallel. I used the CUI CMA-4544PF-W from Digikey and used a small project circuit board to physically arrange them in a 2 x 2 config. Then I trimmed up the board.
>>>> 
>>>> For the mic body I found a unused Shure 522 on ebay (some company had them for a conference table system and had a great price). The 522 has an adjustable neck height and a PTT (with lock). I gutted the body and fitted the new electret element assembly as well as used a 3' TRRS patch cable that I cut 1 end off for the mic cable, it also had 90 deg ends.
>>>> 
>>>> I am pleased with the physical results as well as very good audio reports I am receiving from the regulars that know my signal, still not to the level of my FTDX5000MP but getting better with each tweak and DSP update (using 1.32 which has made a noticeable improvement). I am using a healthy level of compression and mic gain that shows a solid 5 bars.
>>>> 
>>> 
>>> 
>>> -- 
>>> 73,
>>> 
>>> Gary K9GS
>>> 
>>> Greater Milwaukee DX Association: http://www.gmdxa.org
>>> Society of Midwest Contesters: http://www.w9smc.com
>>> CW Ops #1032   http://www.cwops.org
>>> 
>>> ************************************************
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