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Bernhard.Horst

Re: Microham Microkeyer II, RFI in mike with my K3

Hi Guy,

Fully agree with your statement, but as stated I have chokes in all Coax, rotor and control cables.
I am using double shielded USB cables, extra grounding for each device…no idea what else could be don.
Regarding the 2 Ohm, there is a recommendation by Microham to check that the USB / Molex connector resistance should not exceed 5 Ohm otherwise your PC has a USB/Chassis grounding problem.

I had RFI in the Microham already with 300Wtts…now I can run 1200Watts without any problems with is over the legal limit over here anyway!

Several HAMs observed problems with the Microham and in combination with K3/other rigs.
The cheap homebrew USB/Soundcard interface works now, that’s all what counts.

73
Bernie
DL5RDP

Von: [hidden email] [mailto:[hidden email]] Im Auftrag von Guy Olinger K2AV
Gesendet: Montag, 15. Februar 2016 18:15
An: Horst Bernhard, MZ-LR; Elecraft Reflector
Betreff: [Elecraft] Microham Microkeyer II, RFI in mike with my K3

Hi Bernie,

If you are running QRO over your roof, your RFI proofing needs to be perfect. Your situation is only exceeded in nastiness by being next door to a 50 kW AM station and maybe not then. Your induced common mode RF voltages on conductors can be double and triple the desired signal voltages on the cables and ridiculously more than microphone voltages.

One CAN get lucky and get by, but if one does it's only by dumb blind luck and any change to cable routing or position and count of station equipment can disable or polute electronic functions.

If you succumb to the temptation to attribute the changes to the last thing changed or moved, you will be sent down the rabbit hole to join company with Alice and the Mad Hatter where nothing makes sense any more. This can include complaints to manufacturers straight from Wonderland requiring apologies afterward. Been there, done that. Know whereof I speak.

It is quite probable that replacing the box changed cable specifics. Any connection that is not a tenth of an ohm or less needs to be replaced or repaired. I have no idea where you got 2 ohms as a satisfactory connection resistance. Maybe the USB signal itself will tolerate that under otherwise non-stressed circumstances but it's far away out of bounds for RFI proofing.

In your case, QRO on the roof, you need to take maximum anti-RF measures on **ALL** conductors in the shack. Otherwise just changing orientation of cables may remove or incite RFI, or worse makes RFI intermittent leading to suspicions of poltergeist.

I have finally gotten to the point where all retail audio cables need to be replaced with soldered coax or shielded pairs with WOVEN shields. ESPECIALLY audio cables terminated in RCA plugs which typically have the cheapest shields known to man. No retail manufacturer is testing them for RFI susceptibility in rooftop QRO conditions.

There is a good selection of shielded pair and coax cable with Teflon dielectric/insulation and woven shields easily soldered to *quality* RCA plugs or other connectors without melting the wire.

I know that QRO on the roof is all that's available for many folks. Just understand that's the very stiffest possible demand on all RFI proofing issues. No cheapies, no short cuts, no omissions allowed in the protocol.

73, Guy K2AV

On Monday, February 15, 2016, <[hidden email]<javascript:_e(%7B%7D,'cvml','[hidden email]');>> 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 problems are 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:[hidden email]]
Gesendet: Freitag, 12. Februar 2016 14:15
An: [hidden email]<mailto:[hidden email]>
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, [hidden email]<mailto:[hidden email]> 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
>

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Jim Brown-10

Re: Microham Microkeyer II, RFI in mike with my K3

Bernhard,

It's NOT common mode, it's the simple fact that the audio interface is a
mess. The antenna on the roof transmitting high power is doing its job,
putting a lot of RF in the shack. If it didn't (based on proxmiity), it
would be a lousy antenna. The problem is that the interface (wiring plus
electronics plus termination) does not reject RF because it fails to
conform to fundamental principles that reject RF. That is, every cable
must be a transmission line, every shield must be terminated at the
shielding enclosure of the equipment at both ends, and every equipment
chassis must have a short, fat, bond to every other equipment chassis.
Yes, the signal is audio, but the interference is RF, and it takes
proper transmission line techniques to reject that RF.

I have VERY limited experience with MicroHam, but the jumble of wires
that I encountered with the MicroHam unit at W6OAT violated all
principles of good engineering practice for operation in a high RF
environment. It was nothing more than a multipin connector with a lot of
wires soldered to that connector. Indeed, it would darn near impossible
to do it right without starting from scratch withunit a properly made
cable from the MicroHam unit to the radio, with each signal path having
its own coaxial cable.

I have no idea if that describes ALL MicroHam units, but it does
describe Rusty's. And don't ask the model number -- I was so disgusted
by what I saw that I just rolled my eyes.

73, Jim K9YC

On Mon,2/15/2016 10:43 PM, [hidden email] wrote:

> Hi Guy,
>
> Fully agree with your statement, but as stated I have chokes in all Coax, rotor and control cables.
> I am using double shielded USB cables, extra grounding for each device…no idea what else could be don.
> Regarding the 2 Ohm, there is a recommendation by Microham to check that the USB / Molex connector resistance should not exceed 5 Ohm otherwise your PC has a USB/Chassis grounding problem.
>
> I had RFI in the Microham already with 300Wtts…now I can run 1200Watts without any problems with is over the legal limit over here anyway!
>
> Several HAMs observed problems with the Microham and in combination with K3/other rigs.
> The cheap homebrew USB/Soundcard interface works now, that’s all what counts.
>
> 73
> Bernie
> DL5RDP
>
> Von: [hidden email] [mailto:[hidden email]] Im Auftrag von Guy Olinger K2AV
> Gesendet: Montag, 15. Februar 2016 18:15
> An: Horst Bernhard, MZ-LR; Elecraft Reflector
> Betreff: [Elecraft] Microham Microkeyer II, RFI in mike with my K3
>
> Hi Bernie,
>
> If you are running QRO over your roof, your RFI proofing needs to be perfect. Your situation is only exceeded in nastiness by being next door to a 50 kW AM station and maybe not then. Your induced common mode RF voltages on conductors can be double and triple the desired signal voltages on the cables and ridiculously more than microphone voltages.
>
> One CAN get lucky and get by, but if one does it's only by dumb blind luck and any change to cable routing or position and count of station equipment can disable or polute electronic functions.
>
> If you succumb to the temptation to attribute the changes to the last thing changed or moved, you will be sent down the rabbit hole to join company with Alice and the Mad Hatter where nothing makes sense any more. This can include complaints to manufacturers straight from Wonderland requiring apologies afterward. Been there, done that. Know whereof I speak.
>
> It is quite probable that replacing the box changed cable specifics. Any connection that is not a tenth of an ohm or less needs to be replaced or repaired. I have no idea where you got 2 ohms as a satisfactory connection resistance. Maybe the USB signal itself will tolerate that under otherwise non-stressed circumstances but it's far away out of bounds for RFI proofing.
>
> In your case, QRO on the roof, you need to take maximum anti-RF measures on **ALL** conductors in the shack. Otherwise just changing orientation of cables may remove or incite RFI, or worse makes RFI intermittent leading to suspicions of poltergeist.
>
> I have finally gotten to the point where all retail audio cables need to be replaced with soldered coax or shielded pairs with WOVEN shields. ESPECIALLY audio cables terminated in RCA plugs which typically have the cheapest shields known to man. No retail manufacturer is testing them for RFI susceptibility in rooftop QRO conditions.
>
> There is a good selection of shielded pair and coax cable with Teflon dielectric/insulation and woven shields easily soldered to *quality* RCA plugs or other connectors without melting the wire.
>
> I know that QRO on the roof is all that's available for many folks. Just understand that's the very stiffest possible demand on all RFI proofing issues. No cheapies, no short cuts, no omissions allowed in the protocol.
>
> 73, Guy K2AV
>
> On Monday, February 15, 2016, <[hidden email]<javascript:_e(%7B%7D,'cvml','[hidden email]');>> 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 problems are 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:[hidden email]]
> Gesendet: Freitag, 12. Februar 2016 14:15
> An: [hidden email]<mailto:[hidden email]>
> 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, [hidden email]<mailto:[hidden email]> 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
>>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]<mailto:[hidden email]>
>
>
> --
> Sent via Gmail Mobile on my iPhone
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]

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Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

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Joe Subich, W4TV-4

Re: Microham Microkeyer II, RFI in mike with my K3

Jim,

On 2/16/2016 2:04 AM, Jim Brown wrote:
> Indeed, it would darn near impossible to do it right without starting
> from scratch withunit a properly made cable from the MicroHam unit to
> the radio, with each signal path having its own coaxial cable.

Please confine your comments to areas where you are knowledgeable. The
microHAM cables *DO* use a separate coaxial cable (or shielded twisted
pair) for each signal path. The shields are connected to the shell of
the respective connector on each end of the cable. With properly
designed transceivers, this design will minimize RFI issues. When good
engineering practice is used in the station installation - including
antenna systems - there should be no RFI problems with a properly
implemented microKEYER II, MK2R+ or micro2R system.

Schematics for every microHAM cable are available from the support area
at www.microham.com or www.microHAM-USA.com/support.html.

73,

... Joe, W4TV

On 2/16/2016 2:04 AM, Jim Brown wrote:

> Bernhard,
>
> It's NOT common mode, it's the simple fact that the audio interface is a
> mess. The antenna on the roof transmitting high power is doing its job,
> putting a lot of RF in the shack. If it didn't (based on proxmiity), it
> would be a lousy antenna. The problem is that the interface (wiring plus
> electronics plus termination) does not reject RF because it fails to
> conform to fundamental principles that reject RF. That is, every cable
> must be a transmission line, every shield must be terminated at the
> shielding enclosure of the equipment at both ends, and every equipment
> chassis must have a short, fat, bond to every other equipment chassis.
> Yes, the signal is audio, but the interference is RF, and it takes
> proper transmission line techniques to reject that RF.
>
> I have VERY limited experience with MicroHam, but the jumble of wires
> that I encountered with the MicroHam unit at W6OAT violated all
> principles of good engineering practice for operation in a high RF
> environment. It was nothing more than a multipin connector with a lot of
> wires soldered to that connector. Indeed, it would darn near impossible
> to do it right without starting from scratch withunit a properly made
> cable from the MicroHam unit to the radio, with each signal path having
> its own coaxial cable.
>
> I have no idea if that describes ALL MicroHam units, but it does
> describe Rusty's. And don't ask the model number -- I was so disgusted
> by what I saw that I just rolled my eyes.
>
> 73, Jim K9YC
>

john@kk9a.com

Re: Microham Microkeyer II, RFI in mike with my K3

In reply to this post by Bernhard.Horst

I own several DigiKeyer II's and a Micro2R and I have never noticed any
RFI issue. I have done nothing special in my installation to avoid RFI,
but I do eventually intend to bond all of my equipment per K9YC's site. I
have not used the Micro2R with an Elecraft on SSB yet (except into a dummy
load), but I have used it with other transceivers. I did use the Micro2R
for K3S headphone audio in last weekends RTTY contest.

John KK9A

Joe Subich, W4TV lists at subich.com
Tue Feb 16 08:54:42 EST 2016
Previous message (by thread): [Elecraft] Microham Microkeyer II, RFI in
mike with my K3

Jim,

On 2/16/2016 2:04 AM, Jim Brown wrote:
> Indeed, it would darn near impossible to do it right without starting
> from scratch withunit a properly made cable from the MicroHam unit to
> the radio, with each signal path having its own coaxial cable.

Please confine your comments to areas where you are knowledgeable. The
microHAM cables *DO* use a separate coaxial cable (or shielded twisted
pair) for each signal path. The shields are connected to the shell of
the respective connector on each end of the cable. With properly
designed transceivers, this design will minimize RFI issues. When good
engineering practice is used in the station installation - including
antenna systems - there should be no RFI problems with a properly
implemented microKEYER II, MK2R+ or micro2R system.

Schematics for every microHAM cable are available from the support area
at www.microham.com or www.microHAM-USA.com/support.html.

73,

... Joe, W4TV

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

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Please help support this email list: http://www.qsl.net/donate.html
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Bernhard.Horst

Re: Microham Microkeyer II, RFI in mike with my K3

In reply to this post by Joe Subich, W4TV-4

Joe,

I can only confirm what Jim has written and this undermines my findings.

Putting ferrites in the Original Microham cables improves the situation but does not solve it.
I got feedback with similar problems when antennas are in close proximity, again only with Microham interfaces. Others work

Be happy when in works in your environment.

Lets close this thread, I found my solution that works but lost confidence in the Microkeyer II.

73s
Bernhard

-----Ursprüngliche Nachricht-----
Von: Joe Subich, W4TV [mailto:[hidden email]]
Gesendet: Dienstag, 16. Februar 2016 14:55
An: [hidden email]
Betreff: Re: [Elecraft] Microham Microkeyer II, RFI in mike with my K3

Jim,

On 2/16/2016 2:04 AM, Jim Brown wrote:
> Indeed, it would darn near impossible to do it right without starting
> from scratch withunit a properly made cable from the MicroHam unit to
> the radio, with each signal path having its own coaxial cable.

Please confine your comments to areas where you are knowledgeable. The
microHAM cables *DO* use a separate coaxial cable (or shielded twisted
pair) for each signal path. The shields are connected to the shell of
the respective connector on each end of the cable. With properly
designed transceivers, this design will minimize RFI issues. When good
engineering practice is used in the station installation - including
antenna systems - there should be no RFI problems with a properly
implemented microKEYER II, MK2R+ or micro2R system.

Schematics for every microHAM cable are available from the support area
at www.microham.com or www.microHAM-USA.com/support.html.

73,

... Joe, W4TV

On 2/16/2016 2:04 AM, Jim Brown wrote:

Jim Brown-10

Re: Microham Microkeyer II, RFI in mike with my K3

In reply to this post by Joe Subich, W4TV-4

Joe,

Perhaps that's what you're selling now, and if it is, that's great. But
what I described is what is at W6OAT. As it happens, I rode into San
Francisco tonight with him to meet a visiting JA contester for dinner.
He confirmed that what I wrote was an accurate description of what's in
his station. He's agreed to grab a few photos that I'll be happy to send
you if you would like to refresh your memory.

73, Jim K9YC

On Tue,2/16/2016 5:54 AM, Joe Subich, W4TV wrote:

>
> Jim,
>
> On 2/16/2016 2:04 AM, Jim Brown wrote:
>> Indeed, it would darn near impossible to do it right without starting
>> from scratch withunit a properly made cable from the MicroHam unit to
>> the radio, with each signal path having its own coaxial cable.
>
> Please confine your comments to areas where you are knowledgeable. The
> microHAM cables *DO* use a separate coaxial cable (or shielded twisted
> pair) for each signal path. The shields are connected to the shell of
> the respective connector on each end of the cable. With properly
> designed transceivers, this design will minimize RFI issues. When good
> engineering practice is used in the station installation - including
> antenna systems - there should be no RFI problems with a properly
> implemented microKEYER II, MK2R+ or micro2R system.
>
> Schematics for every microHAM cable are available from the support
> area at www.microham.com or www.microHAM-USA.com/support.html.
>
> 73,
>
> ... Joe, W4TV
>
>
> On 2/16/2016 2:04 AM, Jim Brown wrote:
>
>> Bernhard,
>>
>> It's NOT common mode, it's the simple fact that the audio interface is a
>> mess. The antenna on the roof transmitting high power is doing its job,
>> putting a lot of RF in the shack. If it didn't (based on proxmiity), it
>> would be a lousy antenna. The problem is that the interface (wiring plus
>> electronics plus termination) does not reject RF because it fails to
>> conform to fundamental principles that reject RF. That is, every cable
>> must be a transmission line, every shield must be terminated at the
>> shielding enclosure of the equipment at both ends, and every equipment
>> chassis must have a short, fat, bond to every other equipment chassis.
>> Yes, the signal is audio, but the interference is RF, and it takes
>> proper transmission line techniques to reject that RF.
>>
>> I have VERY limited experience with MicroHam, but the jumble of wires
>> that I encountered with the MicroHam unit at W6OAT violated all
>> principles of good engineering practice for operation in a high RF
>> environment. It was nothing more than a multipin connector with a lot of
>> wires soldered to that connector. Indeed, it would darn near impossible
>> to do it right without starting from scratch withunit a properly made
>> cable from the MicroHam unit to the radio, with each signal path having
>> its own coaxial cable.
>>
>> I have no idea if that describes ALL MicroHam units, but it does
>> describe Rusty's. And don't ask the model number -- I was so disgusted
>> by what I saw that I just rolled my eyes.
>>
>> 73, Jim K9YC
>>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>

Joe Subich, W4TV-4

Re: Microham Microkeyer II, RFI in mike with my K3

On 2/17/2016 2:05 AM, Jim Brown wrote:
>
> Perhaps that's what you're selling now, and if it is, that's great.

The microHAM supplied cables have been the same from the very start.
Again, schematics are on the web site. The cables consist of special
multi-cable bundles with six individually shielded coaxial cables and
one shielded four wire cable in a common jacket. The outer jacket is
cut back and the individual cables "fan out" to the appropriate jacks
on the transceiver end. The mic cable is separate and in the case of
the DB37-EL-K3R is two individually shielded coaxial cables.

Again, the cables/interfaces work without RFI if the installation uses
good engineering practice. No active external interface will be 100%
"RFI free" if the user fails to keep the RF voltage well below the
levels of the desired signals (~5 mV for dynamic mic audio).

73,

... Joe, W4TV

On 2/17/2016 2:05 AM, Jim Brown wrote:

> Joe,
>
> Perhaps that's what you're selling now, and if it is, that's great. But
> what I described is what is at W6OAT. As it happens, I rode into San
> Francisco tonight with him to meet a visiting JA contester for dinner.
> He confirmed that what I wrote was an accurate description of what's in
> his station. He's agreed to grab a few photos that I'll be happy to send
> you if you would like to refresh your memory.
>
> 73, Jim K9YC
>
> On Tue,2/16/2016 5:54 AM, Joe Subich, W4TV wrote:
>>
>> Jim,
>>
>> On 2/16/2016 2:04 AM, Jim Brown wrote:
>>> Indeed, it would darn near impossible to do it right without starting
>>> from scratch withunit a properly made cable from the MicroHam unit to
>>> the radio, with each signal path having its own coaxial cable.
>>
>> Please confine your comments to areas where you are knowledgeable. The
>> microHAM cables *DO* use a separate coaxial cable (or shielded twisted
>> pair) for each signal path. The shields are connected to the shell of
>> the respective connector on each end of the cable. With properly
>> designed transceivers, this design will minimize RFI issues. When good
>> engineering practice is used in the station installation - including
>> antenna systems - there should be no RFI problems with a properly
>> implemented microKEYER II, MK2R+ or micro2R system.
>>
>> Schematics for every microHAM cable are available from the support
>> area at www.microham.com or www.microHAM-USA.com/support.html.
>>
>> 73,
>>
>> ... Joe, W4TV
>>