[Elecraft] Fwd: Yet another D104 mic wiring question.

[Bob McGraw - K4TAX]

Seems like RF getting  back into the mike or mike circuit.  Be sure the 
Red & Blue wires in the UG8 cable to the radio are correctly wired to 
the switch on the inside  of the base, grip to talk bar switch, and the 
Black & White & Shield which are the audio are correct to the mike 
connector for the radio.  Also try the radio on a dummy load.  If it 
works correct with the dummy load, then sure bet, it is an RFI issue.  
That needs to be corrected.

If you are using  a medium impedance {what ever that is} element, the 
internal preamp in the UG8 base should not be needed.  There's several 
wiring diagrams on the internet, find one and wire the base 
accordingly.   Personally, unless one is using an original D-104 
element, which requires a very high load impedance in the order of 3 
megohms or more, then the "preamp" in the base is not needed and is 
often more problematic than useful.   If you are using the original 
D-104 element, then the preamp is necessary in order for the mike 
element to see a proper impedance and the preamp will drive a lower 
impedance such as found in today's radios.      But in other words "more 
crap = more problems".

I find this site to have good information regarding the D-104 and the 
UG8 stand and how to wire the "make before break switch" and the "break 
before  make switch". http://www.qsl.net/wa2mzf/d104.html 
<http://www.qsl.net/wa2mzf/d104.html>

73
Bob, K4TAX

On 11/8/2015 10:13 PM, Reuben Popp wrote:
> ast,
> I also turned the D104 5K pot to a hair above its bottom extremity.    Now
> blowing or whistling or just plain talking into the mic will cause the K2
> to cut out with a slight bzzt*pop* [from the radio] as the s-meter goes all
> the way to the right and then goes dark.  This happens every time.