Elecraft

Issue 12 re Astron Power Supply

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Alan Bloom

Re: Issue 12 re Astron Power Supply

You're right. If all the devices run from the same 12V power supply and
they are all bonded together, then there is nothing to prevent some of
the transceiver return current flowing in the negative power supply
leads of the other devices. Hopefully the transceiver power leads use
much heavier wire so most of the current will flow in them. And if the
plus and minus leads are close together and tightly twisted then that
should reduce hum and noise coupling.

Ideally every device would have its own 12V power supply, each with
floating ground. Then there would be no "ground loop". (Sorry Jim, I
know you don't like that term.)

Alan N1AL

On 04/16/2018 10:22 PM, Vic Rosenthal wrote:

> But I keep coming back to this: almost every device connected to the power supply has V- connected to ground internally. So if you have, say, a keyer and a transceiver running off the same supply, won’t some of the transceiver’s current flow through the V- line to the keyer, to the case of the keyer via the internal connection, to the station bonding, to the transceiver case and thence to the transceiver V- input?
>
> In short, don’t the accessories fed from the same PS as the transceiver do exactly the same thing as the notorious black wire in the Astron?
>
> Vic 4X6GP
>
>> On 16 Apr 2018, at 23:50, Jim Brown <[hidden email]> wrote:
>>
>> Joe is right and George is WRONG. V- is NOT GROUND, it is the return for DC power. Bonding V- to ground is a BAD idea -- that's why virtually all pro-grade power supplies are built either without the bond or so that the bond can easily be removed.
>>
>> As to those who were confused by my advice -- I thought it was pretty plain.
>>
>> Quite a few posts back, I posted a link to a detailed discussion of this on my website. I published this around 2010-12. I urge those who are confused to study it.
>>
>> http://k9yc.com/PowerSupplyBondingAndAudioDistortion.pdf
>>
>> My detailed advice on station grounding and bonding is the link below. Much of it has been incorporated in Ward Silver's recent ARRL book on the topic, and is referenced in the book. You can buy the book from ARRL, while the pdf on my website is free. :) Joe and Don are right on in their understanding of the NEC, the fundamentals of which I have been paid to teach to audio/video professionals in workshops at conventions.
>>
>> http://k9yc.com/GroundingAndAudio.pdf
>>
>> 73, Jim K9YC
>>
>>> On 4/16/2018 7:06 AM, Joe Subich, W4TV wrote:
>>>
>>> On 2018-04-16 9:28 AM, George Danner wrote:
>>>> Re-Connect it!
>>>
>>> DON'T CONNECT THAT WIRE BETWEEN V- AND CHASSIS CASE!
>>>
>>> Unless you have a substantial *EXTERNAL GROUND CONNECTION*
>>> between your station ground and the electrical system ground
>>> rod, that connection between V- and chassis will bridge the
>>> power system "safety" ground and the station grounding and
>>> put your delicate and expensive equipment between two "grounds"
>>> that can separate by many hundreds of volts in a lightning
>>> event (or equipment failure).
>>>
>>>> We even used ring grounds around studio & transmitter building with
>>>> ground rods every 10' all cad-welded.
>>>
>>> That is proper grounding and bonds all entry points together *OUTSIDE*
>>> the building to prevent grounds from separating. It creates a common
>>> "island" for everything inside the building. However, for the majority
>>> of amateur stations which fail to properly bond the shields of all of
>>> the coaxial cables entering the shack to the electrical system ground
>>> *at the meter*, there is no "island" ... more like an isthmus across
>>> the equipment.
>>>
>>> 73,
>>>
>>> ... Joe, W4TV
>>>
>>>
>>>> On 2018-04-16 9:28 AM, George Danner wrote:
>>>> Re-Connect it!
>>>>
>>>>> From a broadcaster (AM,FM & TV) was in South Florida (lightning capital of
>>>> North America).
>>>>
>>>> The more massive the common (ground, bonding, whatever term you use) for the connection between equipment and the power company ground connection the better.
>>>> We even used ring grounds around studio & transmitter building with ground rods every 10' all cad-welded. This is probably over kill for a ham station; but think as massive as you can.
>>>> Towers at 500' or above had 2 ring grounds and lots of ground rods.
>>>>
>>>> The common for equipment interconnection is for safety first and the reduction of voltage drops on the common lines that can transfer from one piece of equipment to another (us old timers use the term ground loop - not PC any more).
>>>>
>>>> 73 George AI4VZ
>>>>
>>>> -----Original Message----- From: Charlie T
>>>>
>>>> "This greatly increases the chances for damages to station equipment and all other electronic equipment in the household in event of a lightning event."
>>>>
>>>> What is, disconnecting the wire or leaving it in place?
>>>> Your comment can be taken both ways.
>>>>
>>>> 73, Charlie k3ICH
>>>>
>>>>
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>>
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Jim Brown-10

Re: Issue 12 re Astron Power Supply

On 4/16/2018 10:39 PM, Alan wrote:
> If all the devices run from the same 12V power supply and they are all
> bonded together, then there is nothing to prevent some of the
> transceiver return current flowing in the negative power supply leads
> of the other devices.

That is NOT the problem. Have you studied the link I posted?

73, Jim K9YC

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Buck

Re: Issue 12 re Astron Power Supply

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

What is the minimum recommended voltage for the K3S? Using the stock
Elecraft 5' cable, I drop from 13.3 to 12.7 volts on key down.

Buck, k4ia
Honor Roll
8BDXCC
EasyWayHamBooks.com

On 4/16/2018 4:51 PM, Joe Subich, W4TV wrote:

> On 2018-04-16 4:26 PM, hawley, charles j jr wrote:
>> So 4 sets of power pole connectors plus 2 fuses.
>
> Even if the power pole connectors are assembled perfectly and
> mated with optimum tension, the resistance in just the four
> (15 A) power pole connectors in the negative lead is equivalent
> to nearly 40 feet of #12 copper wire!
>
>> The voltage at the rig, K3, now drops a volt when putting out 100
>> Watts.
>
> With the equivalent of 50 feet of power cable (4 connectors plus a
> 10 foot physical cable), I would not be surprised. Assuming 20A
> in transmit (on 15A power poles!), a 1V drop represents 0.05 Ohms
> of total circuit losses .... that's pretty good for 10 feet (x2)
> of cable plus eight connectors (4 in the + lead, 4 in the - lead)
> and the switching device (probably a Schotkey diode). However,
> the 0.05 Ohms in the negative lead is probably ten times higher
> than in a braided bonding connection directly from the K3 chassis
> to the power supply chassis.
>
> I'm surprised that only 75% went through the ground path - that
> indicates the ground path has 1/3 as much resistance as the "right"
> (V- lead) path.
>
> 73,
>
> ... Joe, W4TV
>
>
> On 2018-04-16 4:26 PM, hawley, charles j jr wrote:
>> About 75% went thru the ground path. The 10 ga to the rig went from
>> Astron to a battery switching device in case of power outage, to rig
>> runner and to rig. So 4 sets of power pole connectors plus 2 fuses.
>> I’m thinking of changing some of that too. The voltage at the rig, K3,
>> now drops a volt when putting out 100 Watts.
>>
>> Chuck Jack
>> KE9UW
>>
>> Sent from my iPhone, cjack
>>
>>> On Apr 16, 2018, at 3:14 PM, Wes Stewart <[hidden email]> wrote:
>>>
>>> I would hope that "much of the current..." wasn't really much. The
>>> direct conductor from the negative terminal of the power supply to
>>> the radio should carry the majority of the supply current,
>>>
>>> Wes N7WS
>>>
>>>> On 4/15/2018 7:38 PM, hawley, charles j jr wrote:
>>>> This thread prompted me to check out my Astron vs35m. It had a small
>>>> black wire from -V connected to the bottom of the chassis. Perhaps
>>>> it could be called a case or cabinet...more importantly, it’s what
>>>> the green wire from the line cord is connected to. I disconnected
>>>> the black wire. When it was connected, much of the current that
>>>> would have passed thru the negative power wire from the power supply
>>>> to the rig was shunted thru the green power cord wire, the ground
>>>> buss bar, and other ground connections.
>>>>
>>>> Chuck Jack
>>>> KE9UW
>>>>
>>>
>>> ______________________________________________________________
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>>>
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>>> Please help support this email list: http://www.qsl.net/donate.html
>>> Message delivered to [hidden email]
>> ______________________________________________________________
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David Box-2

Re: Issue 12 re Astron Power Supply

Like all of the "12VDC" rigs made today the IMD on the K3 is sensitive
to input voltage. I would recommend you get the input up into the
14.8VDC range as it will reduce the IMD products. I have mine such that
on CW key down 100W the internal K3s voltmeter reads 14.5VDC which is
basically the reverse protection diode drop from the 14.8VDC input. I
am using a TGElectronics battery booster with about 4 in cable from the
battery booster to the K3s.

Dave K5MWR

On 4/17/2018 1:36 PM, Buck wrote:

> What is the minimum recommended voltage for the K3S? Using the stock
> Elecraft 5' cable, I drop from 13.3 to 12.7 volts on key down.
>
> Buck, k4ia
> Honor Roll
> 8BDXCC
> EasyWayHamBooks.com
>
> On 4/16/2018 4:51 PM, Joe Subich, W4TV wrote:
>> On 2018-04-16 4:26 PM, hawley, charles j jr wrote:
>>> So 4 sets of power pole connectors plus 2 fuses.
>>
>> Even if the power pole connectors are assembled perfectly and
>> mated with optimum tension, the resistance in just the four
>> (15 A) power pole connectors in the negative lead is equivalent
>> to nearly 40 feet of #12 copper wire!
>>
>>> The voltage at the rig, K3, now drops a volt when putting out 100
>>> Watts.
>>
>> With the equivalent of 50 feet of power cable (4 connectors plus a
>> 10 foot physical cable), I would not be surprised. Assuming 20A
>> in transmit (on 15A power poles!), a 1V drop represents 0.05 Ohms
>> of total circuit losses .... that's pretty good for 10 feet (x2)
>> of cable plus eight connectors (4 in the + lead, 4 in the - lead)
>> and the switching device (probably a Schotkey diode). However,
>> the 0.05 Ohms in the negative lead is probably ten times higher
>> than in a braided bonding connection directly from the K3 chassis
>> to the power supply chassis.
>>
>> I'm surprised that only 75% went through the ground path - that
>> indicates the ground path has 1/3 as much resistance as the "right"
>> (V- lead) path.
>>
>> 73,
>>
>> ... Joe, W4TV
>>
>>
>> On 2018-04-16 4:26 PM, hawley, charles j jr wrote:
>>> About 75% went thru the ground path. The 10 ga to the rig went from
>>> Astron to a battery switching device in case of power outage, to rig
>>> runner and to rig. So 4 sets of power pole connectors plus 2 fuses.
>>> I’m thinking of changing some of that too. The voltage at the rig,
>>> K3, now drops a volt when putting out 100 Watts.
>>>
>>> Chuck Jack
>>> KE9UW
>>>
>>> Sent from my iPhone, cjack
>>>
>>>> On Apr 16, 2018, at 3:14 PM, Wes Stewart <[hidden email]>
>>>> wrote:
>>>>
>>>> I would hope that "much of the current..." wasn't really much. The
>>>> direct conductor from the negative terminal of the power supply to
>>>> the radio should carry the majority of the supply current,
>>>>
>>>> Wes N7WS
>>>>
>>>>> On 4/15/2018 7:38 PM, hawley, charles j jr wrote:
>>>>> This thread prompted me to check out my Astron vs35m. It had a
>>>>> small black wire from -V connected to the bottom of the chassis.
>>>>> Perhaps it could be called a case or cabinet...more importantly,
>>>>> it’s what the green wire from the line cord is connected to. I
>>>>> disconnected the black wire. When it was connected, much of the
>>>>> current that would have passed thru the negative power wire from
>>>>> the power supply to the rig was shunted thru the green power cord
>>>>> wire, the ground buss bar, and other ground connections.
>>>>>
>>>>> Chuck Jack
>>>>> KE9UW
>>>>>
>>>>
>>>> ______________________________________________________________
>>>> 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]
>>> ______________________________________________________________
>>> 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]
>>>
>> ______________________________________________________________
>> 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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>
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Buck

Re: Issue 12 re Astron Power Supply

Well, well. The meter on the front of the Astron 35 says 14.5 volts. My
DVM across the output says 13.5. No wonder my front panel reads 13.3 in
receive mode.

Looks like a calibration is in order. I didn't realize they could get
"off." Instructions available on the Internet. You can adjust both the
output and the meter.

k4ia, Buck
K3# 101
Honor Roll 8B DXCC
EasyWayHamBooks.com

On 4/17/2018 2:45 PM, David Box wrote:

> Like all of the "12VDC" rigs made today the IMD on the K3 is sensitive
> to input voltage. I would recommend you get the input up into the
> 14.8VDC range as it will reduce the IMD products. I have mine such that
> on CW key down 100W the internal K3s voltmeter reads 14.5VDC which is
> basically the reverse protection diode drop from the 14.8VDC input. I
> am using a TGElectronics battery booster with about 4 in cable from the
> battery booster to the K3s.
>
> Dave K5MWR
>
>
>
> On 4/17/2018 1:36 PM, Buck wrote:
>> What is the minimum recommended voltage for the K3S? Using the stock
>> Elecraft 5' cable, I drop from 13.3 to 12.7 volts on key down.
>>
>> Buck, k4ia
>> Honor Roll
>> 8BDXCC
>> EasyWayHamBooks.com
>>
>> On 4/16/2018 4:51 PM, Joe Subich, W4TV wrote:
>>> On 2018-04-16 4:26 PM, hawley, charles j jr wrote:
>>>> So 4 sets of power pole connectors plus 2 fuses.
>>>
>>> Even if the power pole connectors are assembled perfectly and
>>> mated with optimum tension, the resistance in just the four
>>> (15 A) power pole connectors in the negative lead is equivalent
>>> to nearly 40 feet of #12 copper wire!
>>>
>>>> The voltage at the rig, K3, now drops a volt when putting out 100
>>>> Watts.
>>>
>>> With the equivalent of 50 feet of power cable (4 connectors plus a
>>> 10 foot physical cable), I would not be surprised. Assuming 20A
>>> in transmit (on 15A power poles!), a 1V drop represents 0.05 Ohms
>>> of total circuit losses .... that's pretty good for 10 feet (x2)
>>> of cable plus eight connectors (4 in the + lead, 4 in the - lead)
>>> and the switching device (probably a Schotkey diode). However,
>>> the 0.05 Ohms in the negative lead is probably ten times higher
>>> than in a braided bonding connection directly from the K3 chassis
>>> to the power supply chassis.
>>>
>>> I'm surprised that only 75% went through the ground path - that
>>> indicates the ground path has 1/3 as much resistance as the "right"
>>> (V- lead) path.
>>>
>>> 73,
>>>
>>> ... Joe, W4TV
>>>
>>>
>>> On 2018-04-16 4:26 PM, hawley, charles j jr wrote:
>>>> About 75% went thru the ground path. The 10 ga to the rig went from
>>>> Astron to a battery switching device in case of power outage, to rig
>>>> runner and to rig. So 4 sets of power pole connectors plus 2 fuses.
>>>> I’m thinking of changing some of that too. The voltage at the rig,
>>>> K3, now drops a volt when putting out 100 Watts.
>>>>
>>>> Chuck Jack
>>>> KE9UW
>>>>
>>>> Sent from my iPhone, cjack
>>>>
>>>>> On Apr 16, 2018, at 3:14 PM, Wes Stewart <[hidden email]>
>>>>> wrote:
>>>>>
>>>>> I would hope that "much of the current..." wasn't really much. The
>>>>> direct conductor from the negative terminal of the power supply to
>>>>> the radio should carry the majority of the supply current,
>>>>>
>>>>> Wes N7WS
>>>>>
>>>>>> On 4/15/2018 7:38 PM, hawley, charles j jr wrote:
>>>>>> This thread prompted me to check out my Astron vs35m. It had a
>>>>>> small black wire from -V connected to the bottom of the chassis.
>>>>>> Perhaps it could be called a case or cabinet...more importantly,
>>>>>> it’s what the green wire from the line cord is connected to. I
>>>>>> disconnected the black wire. When it was connected, much of the
>>>>>> current that would have passed thru the negative power wire from
>>>>>> the power supply to the rig was shunted thru the green power cord
>>>>>> wire, the ground buss bar, and other ground connections.
>>>>>>
>>>>>> Chuck Jack
>>>>>> KE9UW
>>>>>>
>>>>>
>>>>> ______________________________________________________________
>>>>> 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]
>>>> ______________________________________________________________
>>>> 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]
>>>>
>>> ______________________________________________________________
>>> Elecraft mailing list
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>>> 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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>
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