[Elecraft] Microham Microkeyer II, RFI in mike with my K3

[Joe Subich, W4TV]

> just an update..the Microham Microkeyer II has definitely a problem
 > with RF!

microKEYER II does not have a problem with RF.  You must have an
exceptional problem with common mode RF on your feedline(s) and
that would impact *any* interface in the mic line.

 > I replaced the Microkeyer with a homebrew USB and soundcard
 > interface (Built in 2008) and made new cable distribution box..And
 > the problems are gone.

Unless your homebrew interface includes mic handling circuits with
a wide range preamp, your test in meaningless.  Any change in cable
length can make significant differences in RFI as it moves the high
voltage point.

73,

    ... Joe, W4TV


On 2/15/2016 2:20 AM, Bernhard.Horst at bmw.de wrote:
> Dear all,
>
> just an update..the Microham Microkeyer II has definitely a problem with RF!
> I replaced the Microkeyer with a homebrew USB and soundcard
> interface (Built in 2008) and made new cable distribution box..And
> the problemsare gone.
>
> I have S-NO 280 on the microkeyer..hope the newer ones are better. But definitely not my kind of solution for that cost!
>
> 73s
> Bernie
> DL5RDP
>
> -----Ursprüngliche Nachricht-----
> Von: Joe Subich, W4TV [mailto:lists at subich.com]
> Gesendet: Freitag, 12. Februar 2016 14:15
> An: elecraft at mailman.qth.net
> Betreff: Re: [Elecraft] Microham Microkeyer II, RFI in mike with my K3
>
>
>> As I recall, I used pin 7 for the mic ground and pin 8 for the PTT
>> ground. In a brief test it worked ok into a dummy load. Is this not
>> correct?
>
> That is correct although with the K3/K3S since the Elecraft mic RFI
> change it should not matter (both pin 7 and pin 8 are connected to
> the "ground" foil on the front panel circuit board).
>
> Early K3 front panels included an RF choke in the mic *and* PTT returns
> which made the "pin 1 problem" much worse.  With the RF choke removed
> (bypassed) the issue is significantly reduced but there may still be a
> problem if the overall station installation has any "RF on the coax."
>
> 73,
>
>     ... Joe, W4TV
>
>
> On 2/12/2016 7:59 AM, john at kk9a.com wrote:
>> This week I wired rewired my MicroHAM Micro2R cables for K3S's.  As I
>> recall, I used pin 7 for the mic ground and pin 8 for the PTT ground. In a
>> brief test it worked ok into a dummy load. Is this not correct?
>>
>> John KK9A
>>
>