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GND Connection Between KX3 & KXPA100

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Paul Bousquet

GND Connection Between KX3 & KXPA100

Just wondering how important it is to have connect the GND terminals between the KX3 and the KXPA100 amp. The KXPA100 manual states the station ground should be connected to the KXPA100 GND thumbscrew. I was just wondering since there are many cables connected between the two if the additional GND connection is truly necessary.

PS: This is my first attempt at communicating on the list and I just wanted to say how helpful it has been. I have spent many hours searching and getting information perviously posted.

Thanks, Paul
N1PEB
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stan levandowski

Re: GND Connection Between KX3 & KXPA100

I just bought a KXPA100 and I'm not using any "ground" between it and
the KX3. My station is on the second floor and I use a balanced antenna
in my attic so I don't have either a "station ground" beyond the house
wiring's 3rd prong nor do I have an "RF ground." I have no problems and
no RFI either.

I'll be interested in whatever answers are posted here.

73, Stan WB2LQF

On Tue, Nov 25, 2014 at 10:36 AM, Paul Bousquet wrote:

> Just wondering how important it is to have connect the GND terminals
> between the KX3 and the KXPA100 amp. The KXPA100 manual states the
> station ground should be connected to the KXPA100 GND thumbscrew. I
> was just wondering since there are many cables connected between the
> two if the additional GND connection is truly necessary.
>
> PS: This is my first attempt at communicating on the list and I just
> wanted to say how helpful it has been. I have spent many hours
> searching and getting information perviously posted.
>
> Thanks, Paul
> N1PEB
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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>

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Don Wilhelm-4

Re: GND Connection Between KX3 & KXPA100

In reply to this post by Paul Bousquet

Paul,

It is wise to bond the KXPA100 to the station ground to combat noise and
RFI. In fact bonding everything in the station together with heavy wire
or braid can cure many "strange happenings".

Other than that, you are correct that there is no need from a signalling
connection standpoint to bond the KX3 to the KXPA100. Bonding the
station equipment together and to a station ground point is to keep all
the gear at the same potential and can assist with such things as
extraneous noise pickup, stray RF and other electrical annoyances.

While on the subject of grounding, remember that NEC code requires that
all ground rods and wires be connected back to the utility ground rod
with heavy gauge wire (#6 or larger). This is a safety consideration
and has nothing to do with the proper functioning of your equipment.

73,
Don W3FPR

PS: Your first post is just fine.

On 11/25/2014 10:36 AM, Paul Bousquet wrote:
> Just wondering how important it is to have connect the GND terminals between the KX3 and the KXPA100 amp. The KXPA100 manual states the station ground should be connected to the KXPA100 GND thumbscrew. I was just wondering since there are many cables connected between the two if the additional GND connection is truly necessary.
>
> PS: This is my first attempt at communicating on the list and I just wanted to say how helpful it has been. I have spent many hours searching and getting information perviously posted.
>
>

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Jim Brown-10

Re: GND Connection Between KX3 & KXPA100

On Tue,11/25/2014 8:08 AM, Don Wilhelm wrote:
> Bonding the station equipment together and to a station ground point
> is to keep all the gear at the same potential and can assist with such
> things as extraneous noise pickup, stray RF and other electrical
> annoyances.

Excellent advice. And there are other good reasons.

Here's a talk I did this fall at Pacificon on the topic of grounding and
bonding.

http://k9yc.com/GroundingAndAudio.pdf

73, Jim K9YC
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Eric Buggee; VK3AX

Re: GND Connection Between KX3 & KXPA100

Hi all,

One additional comment regarding grounding for RF interference,
extraneous noise & elecrical safety considerations is that the preferred
method for grounding should be:

Single point grounding, ie all rig & amplifier ground connections
should be taken from a single point, (shack grounding buss).

Relying on "daisy chain" grounding for example: through coax
cable(s) & their connectors; Rig > Amp > tuner > tground point can be
the source of intermittent RFI & distortion

problems that can be difficult to nail. This approach to grounding
should NOT be used for the foregoing stated reasons.

Eric, VK3AX. Retired EMC engineer.

On 11/26/2014 4:21 AM, Jim Brown wrote:

> On Tue,11/25/2014 8:08 AM, Don Wilhelm wrote:
>> Bonding the station equipment together and to a station ground point
>> is to keep all the gear at the same potential and can assist with
>> such things as extraneous noise pickup, stray RF and other electrical
>> annoyances.
>
> Excellent advice. And there are other good reasons.
>
> Here's a talk I did this fall at Pacificon on the topic of grounding
> and bonding.
>
> http://k9yc.com/GroundingAndAudio.pdf
>
> 73, Jim K9YC
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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> 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]
>

Jim Brown-10

Re: GND Connection Between KX3 & KXPA100

On Tue,11/25/2014 2:46 PM, Eric Buggee wrote:
> One additional comment regarding grounding for RF interference,
> extraneous noise & elecrical safety considerations is that the
> preferred method for grounding should be:
>
> Single point grounding, ie all rig & amplifier ground connections
> should be taken from a single point, (shack grounding buss).

There is a significant fallacy in this. See the linked tutorial.

73, Jim K9YC
Vice-Chair Audio Engineering Society Standards Committee WG on EMC
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Don Wilhelm-4

Re: GND Connection Between KX3 & KXPA100

In reply to this post by Eric Buggee; VK3AX

Eric,

In many cases, the problem being dealt with is the currents flowing
through the "grounds" and complicated by what K9YC refers to as the "pin
1 problem" in that the connectors for audio and RF paths are grounded to
the circuit boards, but not to the enclosure (the enclosure *should*
shield the boards and inter-connects, but it does not in modern gear).

While a single point star grounding system may be best from an EMC point
of view, it is not the best for noise reduction and 'sneak paths' in the
gear we deal with in a ham station. In fact the multiple paths to that
single point ground can create currents in the grounding system giving
rise to noise in the gear that we are trying to reduce the noise.

Review Jim's presentation on grounding in entirety. Jim does speak from
many years of experience dealing with noise and sneak paths in
professional audio installations, and I respect his opinions based on
his years of experience dealing with these issues.

If you have no ground current induced noise and are only striving for a
lightning protection grounding scheme, then yes, the single point
grounding system is the way to go, but that is not the situation in the
modern ham station where we have to deal with audio and digital paths
to/from computers, interface devices, ancillary gear and "who knows
what" to the transceiver. Bonding all equipment together (with a mind
to the path for the audio and RF) will minimize the extraneous noise
currents on the shields between the boxes in the shack which will reduce
the noise level in the receiver.

I too have years of experience with design and testing for EMC
considerations, and as I have indicated, each method of grounding has
its place, but we are not dealing with EMC considerations alone.

73,
Don W3FPR

On 11/25/2014 5:46 PM, Eric Buggee wrote:

> Hi all,
>
> One additional comment regarding grounding for RF interference,
> extraneous noise & elecrical safety considerations is that the
> preferred method for grounding should be:
>
> Single point grounding, ie all rig & amplifier ground connections
> should be taken from a single point, (shack grounding buss).
>
> Relying on "daisy chain" grounding for example: through coax
> cable(s) & their connectors; Rig > Amp > tuner > tground point can be
> the source of intermittent RFI & distortion
>
> problems that can be difficult to nail. This approach to
> grounding should NOT be used for the foregoing stated reasons.
>
> Eric, VK3AX. Retired EMC engineer.
>
>
>
> On 11/26/2014 4:21 AM, Jim Brown wrote:
>> On Tue,11/25/2014 8:08 AM, Don Wilhelm wrote:
>>> Bonding the station equipment together and to a station ground point
>>> is to keep all the gear at the same potential and can assist with
>>> such things as extraneous noise pickup, stray RF and other
>>> electrical annoyances.
>>
>> Excellent advice. And there are other good reasons.
>>
>> Here's a talk I did this fall at Pacificon on the topic of grounding
>> and bonding.
>>
>> http://k9yc.com/GroundingAndAudio.pdf
>>
>> 73, Jim K9YC

Jim Brown-10

Re: GND Connection Between KX3 & KXPA100

On Tue,11/25/2014 3:22 PM, Don Wilhelm wrote:
> While a single point star grounding system may be best from an EMC
> point of view,

The meaning of a single point star grounding system is badly
misunderstood. Likewise, the difference between grounding and bonding is
badly misunderstood. A connection to earth is NOT part of a solution to
RFI/EMC issues. Proper BONDING IS. And the method I've shown in the
tutorial IS best for EMC and for lightning. Remember -- EMC goes from DC
To daylight! About ten years ago, I consulted to a mic manufacturer
about RFI from cell phones to audio systems in meeting rooms of the US
House of Representatives. The primary coupling mechanism was a Pin One
Problem in the FET follower line driver for the electret mics. The cell
phones were running 1W or less, pulse modulated, in the ranges of 900
MHz and above.

73, Jim K9YC
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