K3 - Power cable voltage drop

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K3 - Power cable voltage drop

Elecraft mailing list
I have been using an Astron SS-30M power supply for several years to feed
two K3's.
I use 12ga wire from the power supply to an MFJ-4012 power strip. From the
power strip I use 12ga wire to each K3. Total length from power supply to a
K3 was 8'. Each K3 is set for 100W on 30M into a dummy load.  The K3's were
tested one at a time. The power supply voltage went from 14.38 to 14.30 at
100W.
Both K3's read the same on the K3's internal voltmeter - 14.1V in receive
and 12.7V at 100W setting on the K3's. The P3 read 107W out.
Changed the cable to 10ga wire direct from the power supply to each K3.
Length of each is 7'. Same test. Power supply voltage was still 14.39/14.30.
Voltage on each K3 was now 14.2v. Key down 13.6V. So, 0.6V drop in 7' of
10ga wire.
P3 output was now 114W.
I never transmit with both K3's at the same time.
Just a data point.
73 and Merry Christmas
N2TK, Tony
 

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Re: K3 - Power cable voltage drop

Don Wilhelm
Tony,

While those figures with the 10 gauge wire are good, they would be
better if you ran the K3 power directly from the power supply rather
than from the power distribution strip.

Each connection will have some voltage drop, so in addition to
increasing the wiring gauge, reducing the connection points will help
just as much.

73 Merry Christmas, or Happy Hanukkah whichever you choose to celebrate.
Don W3FPR

On 12/22/2019 10:47 AM, N2TK via Elecraft wrote:

> I have been using an Astron SS-30M power supply for several years to feed
> two K3's.
> I use 12ga wire from the power supply to an MFJ-4012 power strip. From the
> power strip I use 12ga wire to each K3. Total length from power supply to a
> K3 was 8'. Each K3 is set for 100W on 30M into a dummy load.  The K3's were
> tested one at a time. The power supply voltage went from 14.38 to 14.30 at
> 100W.
> Both K3's read the same on the K3's internal voltmeter - 14.1V in receive
> and 12.7V at 100W setting on the K3's. The P3 read 107W out.
> Changed the cable to 10ga wire direct from the power supply to each K3.
> Length of each is 7'. Same test. Power supply voltage was still 14.39/14.30.
> Voltage on each K3 was now 14.2v. Key down 13.6V. So, 0.6V drop in 7' of
> 10ga wire.
> P3 output was now 114W.
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Re: K3 - Power cable voltage drop

Bob McGraw - K4TAX
In reply to this post by Elecraft mailing list
Rid your station of the DC power strip.  It will cause problems. More
connections in the path will be more DC voltage drip.  The radios should
be connected direct to the power supply.

As to the Astron SS-30M, I have 3 of those.  They are great. I did find
the provided DC connections where the wires are inserted into the blocks
and secured with a screw from the side would not accommodate the 4 needs
for DC at my station.    Therefore, I took two pieces of  2" x 10-32
brass machine screw, cut off the head, filed a small flat spot on one
side at the end to make it slightly D shaped.   Inserted that end into
the DC connector and tightened the set screw against the flat spot. 
Then added as needed the brass nuts, flat washers and lock washers,
secured finally by another brass nut.   This in effect gives me very
adequate terminal length to attach as many DC power leads with suitable
ring terminals as needed.  DC resistance has therefore been
minimized.     The 10 ga wire is a good addition for radio power needs.

I also added a dedicated ground between the ground screw on the back of
the radio to the ground screw on the power supply.

73

Bob, K4TAX

12/22/2019 10:47 AM, N2TK via Elecraft wrote:

> I have been using an Astron SS-30M power supply for several years to feed
> two K3's.
> I use 12ga wire from the power supply to an MFJ-4012 power strip. From the
> power strip I use 12ga wire to each K3. Total length from power supply to a
> K3 was 8'. Each K3 is set for 100W on 30M into a dummy load.  The K3's were
> tested one at a time. The power supply voltage went from 14.38 to 14.30 at
> 100W.
> Both K3's read the same on the K3's internal voltmeter - 14.1V in receive
> and 12.7V at 100W setting on the K3's. The P3 read 107W out.
> Changed the cable to 10ga wire direct from the power supply to each K3.
> Length of each is 7'. Same test. Power supply voltage was still 14.39/14.30.
> Voltage on each K3 was now 14.2v. Key down 13.6V. So, 0.6V drop in 7' of
> 10ga wire.
> P3 output was now 114W.
> I never transmit with both K3's at the same time.
> Just a data point.
> 73 and Merry Christmas
> N2TK, Tony
>    
>
> ______________________________________________________________
> 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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Re: K3 - Power cable voltage drop

Elecraft mailing list
In reply to this post by Don Wilhelm
Hi Don,
With the 10ga wire the power distribution strip is not used. There are two runs of 7' each direct from the power supply to a K3. The run is 7' because I have the power supply with the rest of my supplies, router, etc. all mounted underneath my desk to the side to keep the desktop clean. I don't hink 0.6V drop is too much to be concerned with. The amps are in the basement.
In the process of adding Green Heron Everywhere wireless remotes to eliminate the manual switches too.

73 and merry Christmas
N2TK, Tony

-----Original Message-----
From: Don Wilhelm <[hidden email]>
Sent: Sunday, December 22, 2019 11:21 AM
To: [hidden email]; [hidden email]
Subject: Re: [Elecraft] K3 - Power cable voltage drop

Tony,

While those figures with the 10 gauge wire are good, they would be better if you ran the K3 power directly from the power supply rather than from the power distribution strip.

Each connection will have some voltage drop, so in addition to increasing the wiring gauge, reducing the connection points will help just as much.

73 Merry Christmas, or Happy Hanukkah whichever you choose to celebrate.
Don W3FPR

On 12/22/2019 10:47 AM, N2TK via Elecraft wrote:

> I have been using an Astron SS-30M power supply for several years to
> feed two K3's.
> I use 12ga wire from the power supply to an MFJ-4012 power strip. From
> the power strip I use 12ga wire to each K3. Total length from power
> supply to a
> K3 was 8'. Each K3 is set for 100W on 30M into a dummy load.  The K3's
> were tested one at a time. The power supply voltage went from 14.38 to
> 14.30 at 100W.
> Both K3's read the same on the K3's internal voltmeter - 14.1V in
> receive and 12.7V at 100W setting on the K3's. The P3 read 107W out.
> Changed the cable to 10ga wire direct from the power supply to each K3.
> Length of each is 7'. Same test. Power supply voltage was still 14.39/14.30.
> Voltage on each K3 was now 14.2v. Key down 13.6V. So, 0.6V drop in 7'
> of 10ga wire.
> P3 output was now 114W.

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Re: K3 - Power cable voltage drop

Elecraft mailing list
In reply to this post by Bob McGraw - K4TAX
Bob,
The power strip is gone for the K3's. Now direct connections from the PS to each K3.
The power strip is good for replacing the walwarts.
N2TK, Tony

-----Original Message-----
From: [hidden email] <[hidden email]> On Behalf Of Bob McGraw
Sent: Sunday, December 22, 2019 12:45 PM
To: [hidden email]
Subject: Re: [Elecraft] K3 - Power cable voltage drop

Rid your station of the DC power strip.  It will cause problems. More connections in the path will be more DC voltage drip.  The radios should be connected direct to the power supply.

As to the Astron SS-30M, I have 3 of those.  They are great. I did find the provided DC connections where the wires are inserted into the blocks and secured with a screw from the side would not accommodate the 4 needs for DC at my station.    Therefore, I took two pieces of  2" x 10-32 brass machine screw, cut off the head, filed a small flat spot on one side at the end to make it slightly D shaped.   Inserted that end into the DC connector and tightened the set screw against the flat spot. Then added as needed the brass nuts, flat washers and lock washers, secured finally by another brass nut.   This in effect gives me very adequate terminal length to attach as many DC power leads with suitable ring terminals as needed.  DC resistance has therefore been minimized.     The 10 ga wire is a good addition for radio power needs.

I also added a dedicated ground between the ground screw on the back of the radio to the ground screw on the power supply.

73

Bob, K4TAX

12/22/2019 10:47 AM, N2TK via Elecraft wrote:

> I have been using an Astron SS-30M power supply for several years to
> feed two K3's.
> I use 12ga wire from the power supply to an MFJ-4012 power strip. From
> the power strip I use 12ga wire to each K3. Total length from power
> supply to a
> K3 was 8'. Each K3 is set for 100W on 30M into a dummy load.  The K3's
> were tested one at a time. The power supply voltage went from 14.38 to
> 14.30 at 100W.
> Both K3's read the same on the K3's internal voltmeter - 14.1V in
> receive and 12.7V at 100W setting on the K3's. The P3 read 107W out.
> Changed the cable to 10ga wire direct from the power supply to each K3.
> Length of each is 7'. Same test. Power supply voltage was still 14.39/14.30.
> Voltage on each K3 was now 14.2v. Key down 13.6V. So, 0.6V drop in 7'
> of 10ga wire.
> P3 output was now 114W.
> I never transmit with both K3's at the same time.
> Just a data point.
> 73 and Merry Christmas
> N2TK, Tony
>    
>
> ______________________________________________________________
> 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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Re: K3 - Power cable voltage drop

Edward R Cole
In reply to this post by Elecraft mailing list
In my current station layout the rack-mounted Astron-50M is separated
from the radio shelf, so I need a 15-foot run of cable.  The Astron
runs 14.2 vdc.  I have 13.69 v at the main power strip (handles 10ga
wiring).  The primary dc power cable is No. 6 welding cable (more
flexible than std No. 6) so I have a BUSS30 fuse at the main power
strip.  The Astron is capable of 50 amps if the main cable were to
short (cable is rated for a over 200A for welding).

I use the std power cord that came with my K3/10 and see 13.3v
displayed by the K3 in transmit with 10w RF output.  The K3/10 does
not draw a lot of current.  I drive a KXPA100 which has 5-foot
Elecraft power cable (looks like No.12).  I get 100w on all bands
with about 5w drive (only 6m requires 8w drive for 80w output).

I have not measured the voltage at the power-pole connector when in
transmit but should be approx 13.5v based on current draw of 20 A.

I run several high power solid-state amplifiers that draw up to 50A
at 50v so paying attention to dc voltage drop in dc wiring is quite important.

73, Ed - KL7UW
   http://www.kl7uw.com
Dubus-NA Business mail:
   [hidden email]

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Re: K3 - Power cable voltage drop

Bob McGraw - K4TAX
In reply to this post by Elecraft mailing list
I still connect all of the equipment which used walwarts to my power
supply.  I made provisions to have many many DC connections, as
described below,  to my supplies.  All of my DC power leads have the
correct size crimp ring terminal for the application. Never use stranded
wire around a screw.     Thus many problems solved.  I know the DC
distribution strips look cool with their LEDs and fuses and connectors,
and are very easy to use for convenience.  But I find just like AC
strips, are a source of many problems.   I've found many of the AC
strips which have a poor 3rd wire connection.   They are a matter of
convenience and not of reliable functionality.


> As to the Astron SS-30M, I have 3 of those.  They are great. I did find the provided DC connections where the wires are inserted into the blocks and secured with a screw from the side would not accommodate the 4 needs for DC at my station.    Therefore, I took two pieces of  2" x 10-32 brass machine screw, cut off the head, filed a small flat spot on one side at the end to make it slightly D shaped.   Inserted that end into the DC connector and tightened the set screw against the flat spot. Then added as needed the brass nuts, flat washers and lock washers, secured finally by another brass nut.   This in effect gives me very adequate terminal length to attach as many DC power leads with suitable ring terminals as needed.  DC resistance has therefore been minimized.     The 10 ga wire is a good addition for radio power needs.
>
> I also added a dedicated ground between the ground screw on the back of the radio to the ground screw on the power supply.


73

Bob, K4TAX


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Re: K3 - Power cable voltage drop

ke9uw
In reply to this post by Don Wilhelm
I used to run my K3S with an auto turn on Rigrunner which I liked very much, convenient. But the voltage drop was concerning. I go direct now to the rig.

Chuck Jack Hawley
KE9UW

Sent from my iPhone, cjack

> On Dec 22, 2019, at 10:21 AM, Don Wilhelm <[hidden email]> wrote:
>
> Tony,
>
> While those figures with the 10 gauge wire are good, they would be better if you ran the K3 power directly from the power supply rather than from the power distribution strip.
>
> Each connection will have some voltage drop, so in addition to increasing the wiring gauge, reducing the connection points will help just as much.
>
> 73 Merry Christmas, or Happy Hanukkah whichever you choose to celebrate.
> Don W3FPR
>
>> On 12/22/2019 10:47 AM, N2TK via Elecraft wrote:
>> I have been using an Astron SS-30M power supply for several years to feed
>> two K3's.
>> I use 12ga wire from the power supply to an MFJ-4012 power strip. From the
>> power strip I use 12ga wire to each K3. Total length from power supply to a
>> K3 was 8'. Each K3 is set for 100W on 30M into a dummy load.  The K3's were
>> tested one at a time. The power supply voltage went from 14.38 to 14.30 at
>> 100W.
>> Both K3's read the same on the K3's internal voltmeter - 14.1V in receive
>> and 12.7V at 100W setting on the K3's. The P3 read 107W out.
>> Changed the cable to 10ga wire direct from the power supply to each K3.
>> Length of each is 7'. Same test. Power supply voltage was still 14.39/14.30.
>> Voltage on each K3 was now 14.2v. Key down 13.6V. So, 0.6V drop in 7' of
>> 10ga wire.
>> P3 output was now 114W.
> ______________________________________________________________
> 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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Re: K3 - Power cable voltage drop

Jim Brown-10
In reply to this post by Bob McGraw - K4TAX
On 12/22/2019 9:44 AM, Bob McGraw wrote:
> Rid your station of the DC power strip.  It will cause problems. More
> connections in the path will be more DC voltage drip.  The radios should
> be connected direct to the power supply.

Yes and no. My station has direct short runs from a 100Ah Bioenne
LiFePO4 battery to my two K3s. The radio very close to the battery is
#10; the longer run (about five ft) to the radio on the other side of
the desk is two #10s in parallel. This battery is used because it's
operating voltage remains well about 13VDC throughout its discharge
curve (as opposed to the SLA, which is closer to 11.5VDC under load).
The difference results in lower IMD.

The other 12V gear (and LED strips for task lighting) runs from a 100Ah
12V SLA battery through a DC power strip. All the gear is bonded
together. Both batteries are float-charged by spare Thinkpad power
supplies with Genasun charge regulators. The power strips are fine for
low current drain devices, but, as Bob notes, not for the radios.

73, Jim K9YC


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Re: K3 - Power cable voltage drop

Phil Kane-2
In reply to this post by Bob McGraw - K4TAX
On 12/22/2019 9:44 AM, Bob McGraw wrote:

> I also added a dedicated ground between the ground screw on the back of
> the radio to the ground screw on the power supply.

That's for "bonding".  Where do you pick up "ground" - at the radio, at
the PS, or at some other point?

73 de K2ASP - Phil Kane
Elecraft K2/100   s/n 5402

From a Clearing in the Silicon Forest
Beaverton (Washington County) Oregon
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Re: K3 - Power cable voltage drop

Buck
The reliable place to measure the voltage at the K3x is using the supply
voltage display meter in the radio.  I was surprised to find mine was
significantly low.  I thought it was voltage drop but changing the
supply cable didn't make much difference.

Turns out the Astron power supply was more than a volt low and the meter
on the supply had been cranked up to make it appear to be correct.  I
used two separate VOMs to set the power supply and then adjusted the
meter to make it agree.

Moral of the story: don't rely on the meter on the power supply and
assume a low reading at the radio is due solely to voltage drop.



Buck, k4ia
Honor Roll
8BDXCC
EasyWayHamBooks.com

On 12/23/2019 2:26 PM, Phil Kane wrote:

> On 12/22/2019 9:44 AM, Bob McGraw wrote:
>
>> I also added a dedicated ground between the ground screw on the back of
>> the radio to the ground screw on the power supply.
>
> That's for "bonding".  Where do you pick up "ground" - at the radio, at
> the PS, or at some other point?
>
> 73 de K2ASP - Phil Kane
> Elecraft K2/100   s/n 5402
>
>  From a Clearing in the Silicon Forest
> Beaverton (Washington County) Oregon
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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> Post: mailto:[hidden email]
>
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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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Re: K3 - Power cable voltage drop

Bob McGraw - K4TAX
In reply to this post by Phil Kane-2
I do not use a “ground” at the station.  I don’t find or see that it’s needed.  My station has a 4 wire #10 service from the breaker panel to the operating position.  The breakers are single 20A units. This gives me 240V for the amp and a duplex off of each leg.  Thus I maintain a common neutral and common ground to the breaker panel.

Grounding for lightning protection is done outside of the house and that system is bonded back to the AC Mains ground rod below the service entrance.

Bob, K4TAX


Sent from my iPhone

> On Dec 23, 2019, at 1:44 PM, Phil Kane <[hidden email]> wrote:
>
> On 12/22/2019 9:44 AM, Bob McGraw wrote:
>
>> I also added a dedicated ground between the ground screw on the back of
>> the radio to the ground screw on the power supply.
>
> That's for "bonding".  Where do you pick up "ground" - at the radio, at
> the PS, or at some other point?
>
> 73 de K2ASP - Phil Kane
> Elecraft K2/100   s/n 5402
>
> From a Clearing in the Silicon Forest
> Beaverton (Washington County) Oregon
> ______________________________________________________________
> 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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Re: K3 - Power cable voltage drop

Bob McGraw - K4TAX
In reply to this post by Buck
A good, known accurate DVM is an asset to any station.  Use it to determine if the others are accurate.  There are several good brands available.   A DVM that is not accurate is worse than no DVM at all.  

My choice of many years ago is my Fluke 77.   After I tapped it with too much voltage, I sent it to Fluke for repair and calibration.  I am confident when I make a measurement it is accurate without question.

Bob, K4TAX


Sent from my iPhone

> On Dec 23, 2019, at 2:12 PM, Buck <[hidden email]> wrote:
>
> The reliable place to measure the voltage at the K3x is using the supply voltage display meter in the radio.  I was surprised to find mine was significantly low.  I thought it was voltage drop but changing the supply cable didn't make much difference.
>
> Turns out the Astron power supply was more than a volt low and the meter on the supply had been cranked up to make it appear to be correct.  I used two separate VOMs to set the power supply and then adjusted the meter to make it agree.
>
> Moral of the story: don't rely on the meter on the power supply and assume a low reading at the radio is due solely to voltage drop.
>
>
>
> Buck, k4ia
> Honor Roll
> 8BDXCC
> EasyWayHamBooks.com
>
>> On 12/23/2019 2:26 PM, Phil Kane wrote:
>>> On 12/22/2019 9:44 AM, Bob McGraw wrote:
>>> I also added a dedicated ground between the ground screw on the back of
>>> the radio to the ground screw on the power supply.
>> That's for "bonding".  Where do you pick up "ground" - at the radio, at
>> the PS, or at some other point?
>> 73 de K2ASP - Phil Kane
>> Elecraft K2/100   s/n 5402
>> From a Clearing in the Silicon Forest
>> Beaverton (Washington County) Oregon
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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Re: K3 - Power cable voltage drop

ke9uw
I have a Fluke 87...for a couple of decades now. It does it all well.

Chuck Jack Hawley
KE9UW

Sent from my iPhone, cjack

> On Dec 23, 2019, at 10:31 PM, Bob McGraw K4TAX <[hidden email]> wrote:
>
> A good, known accurate DVM is an asset to any station.  Use it to determine if the others are accurate.  There are several good brands available.   A DVM that is not accurate is worse than no DVM at all.  
>
> My choice of many years ago is my Fluke 77.   After I tapped it with too much voltage, I sent it to Fluke for repair and calibration.  I am confident when I make a measurement it is accurate without question.
>
> Bob, K4TAX
>
>
> Sent from my iPhone
>
>> On Dec 23, 2019, at 2:12 PM, Buck <[hidden email]> wrote:
>>
>> The reliable place to measure the voltage at the K3x is using the supply voltage display meter in the radio.  I was surprised to find mine was significantly low.  I thought it was voltage drop but changing the supply cable didn't make much difference.
>>
>> Turns out the Astron power supply was more than a volt low and the meter on the supply had been cranked up to make it appear to be correct.  I used two separate VOMs to set the power supply and then adjusted the meter to make it agree.
>>
>> Moral of the story: don't rely on the meter on the power supply and assume a low reading at the radio is due solely to voltage drop.
>>
>>
>>
>> Buck, k4ia
>> Honor Roll
>> 8BDXCC
>> EasyWayHamBooks.com
>>
>>>> On 12/23/2019 2:26 PM, Phil Kane wrote:
>>>> On 12/22/2019 9:44 AM, Bob McGraw wrote:
>>>> I also added a dedicated ground between the ground screw on the back of
>>>> the radio to the ground screw on the power supply.
>>> That's for "bonding".  Where do you pick up "ground" - at the radio, at
>>> the PS, or at some other point?
>>> 73 de K2ASP - Phil Kane
>>> Elecraft K2/100   s/n 5402
>>> From a Clearing in the Silicon Forest
>>> Beaverton (Washington County) Oregon
>>> ______________________________________________________________
>>> 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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Chuck, KE9UW
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Re: K3 - Power cable voltage drop

Victor Rosenthal 4X6GP
I have a Fluke DVM also. I gulped when I bought it some 30+ years ago, but it was a good decision. It’s like a Snap-On wrench. It just feels right and never let me down.

Victor 4X6GP

> On 25 Dec 2019, at 4:29, hawley, charles j jr <[hidden email]> wrote:
>
> I have a Fluke 87...for a couple of decades now. It does it all well.
>
> Chuck Jack Hawley
> KE9UW
>
> Sent from my iPhone, cjack
>
>> On Dec 23, 2019, at 10:31 PM, Bob McGraw K4TAX <[hidden email]> wrote:
>>
>> A good, known accurate DVM is an asset to any station.  Use it to determine if the others are accurate.  There are several good brands available.   A DVM that is not accurate is worse than no DVM at all.  
>>
>> My choice of many years ago is my Fluke 77.   After I tapped it with too much voltage, I sent it to Fluke for repair and calibration.  I am confident when I make a measurement it is accurate without question.
>>
>> Bob, K4TAX
>>
>>
>> Sent from my iPhone
>>
>>>> On Dec 23, 2019, at 2:12 PM, Buck <[hidden email]> wrote:
>>>
>>> The reliable place to measure the voltage at the K3x is using the supply voltage display meter in the radio.  I was surprised to find mine was significantly low.  I thought it was voltage drop but changing the supply cable didn't make much difference.
>>>
>>> Turns out the Astron power supply was more than a volt low and the meter on the supply had been cranked up to make it appear to be correct.  I used two separate VOMs to set the power supply and then adjusted the meter to make it agree.
>>>
>>> Moral of the story: don't rely on the meter on the power supply and assume a low reading at the radio is due solely to voltage drop.
>>>
>>>
>>>
>>> Buck, k4ia
>>> Honor Roll
>>> 8BDXCC
>>> EasyWayHamBooks.com
>>>
>>>>> On 12/23/2019 2:26 PM, Phil Kane wrote:
>>>>> On 12/22/2019 9:44 AM, Bob McGraw wrote:
>>>>> I also added a dedicated ground between the ground screw on the back of
>>>>> the radio to the ground screw on the power supply.
>>>> That's for "bonding".  Where do you pick up "ground" - at the radio, at
>>>> the PS, or at some other point?
>>>> 73 de K2ASP - Phil Kane
>>>> Elecraft K2/100   s/n 5402
>>>> From a Clearing in the Silicon Forest
>>>> Beaverton (Washington County) Oregon
>>>> ______________________________________________________________
>>>> 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]
> ______________________________________________________________
> Elecraft mailing list
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> 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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Re: K3 - Power cable voltage drop

George Thornton
Concur.

-----Original Message-----
From: [hidden email] <[hidden email]> On Behalf Of Vic Rosenthal
Sent: Tuesday, December 24, 2019 9:34 PM
To: hawley, charles j jr <[hidden email]>
Cc: [hidden email]
Subject: Re: [Elecraft] K3 - Power cable voltage drop

I have a Fluke DVM also. I gulped when I bought it some 30+ years ago, but it was a good decision. It’s like a Snap-On wrench. It just feels right and never let me down.

Victor 4X6GP

> On 25 Dec 2019, at 4:29, hawley, charles j jr <[hidden email]> wrote:
>
> I have a Fluke 87...for a couple of decades now. It does it all well.
>
> Chuck Jack Hawley
> KE9UW
>
> Sent from my iPhone, cjack
>
>> On Dec 23, 2019, at 10:31 PM, Bob McGraw K4TAX <[hidden email]> wrote:
>>
>> A good, known accurate DVM is an asset to any station.  Use it to determine if the others are accurate.  There are several good brands available.   A DVM that is not accurate is worse than no DVM at all.  
>>
>> My choice of many years ago is my Fluke 77.   After I tapped it with too much voltage, I sent it to Fluke for repair and calibration.  I am confident when I make a measurement it is accurate without question.
>>
>> Bob, K4TAX
>>
>>
>> Sent from my iPhone
>>
>>>> On Dec 23, 2019, at 2:12 PM, Buck <[hidden email]> wrote:
>>>
>>> The reliable place to measure the voltage at the K3x is using the supply voltage display meter in the radio.  I was surprised to find mine was significantly low.  I thought it was voltage drop but changing the supply cable didn't make much difference.
>>>
>>> Turns out the Astron power supply was more than a volt low and the meter on the supply had been cranked up to make it appear to be correct.  I used two separate VOMs to set the power supply and then adjusted the meter to make it agree.
>>>
>>> Moral of the story: don't rely on the meter on the power supply and assume a low reading at the radio is due solely to voltage drop.
>>>
>>>
>>>
>>> Buck, k4ia
>>> Honor Roll
>>> 8BDXCC
>>> EasyWayHamBooks.com
>>>
>>>>> On 12/23/2019 2:26 PM, Phil Kane wrote:
>>>>> On 12/22/2019 9:44 AM, Bob McGraw wrote:
>>>>> I also added a dedicated ground between the ground screw on the
>>>>> back of the radio to the ground screw on the power supply.
>>>> That's for "bonding".  Where do you pick up "ground" - at the
>>>> radio, at the PS, or at some other point?
>>>> 73 de K2ASP - Phil Kane
>>>> Elecraft K2/100   s/n 5402
>>>> From a Clearing in the Silicon Forest Beaverton (Washington County)
>>>> Oregon
>>>> ______________________________________________________________
>>>> 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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> 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
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Re: K3 - Power cable voltage drop

Keith Trinity WE6R
In reply to this post by Elecraft mailing list
Notes for all;
Check the K3 config menu item "ADC REF".   If at 5.00 it is probably at
default.
(if at 4.00 a glitch occurred, probably during FW update, and will FUBAR
the internal metering. Set to 5.00 or read on).
(I check this during checkout, so if it has been in for Service, it
should be OK).

Higher accuracy of the K3 items like the internal Volt-Meter can be had
if this is set properly.
With a known external meter on Pin 2 to ground of the 15 pin ACCY connector;
Go into config menu ADC REF and set it.

Also you can stick your probes into the Anderson connectors at the back
of the radio during full power TX to see the actual voltage to the radio.
(I have a digital LED meter connected  with small wires to the Anderson
supply wire right at the back of the radio on my K3 test bench).
Keith WE6R
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Re: K3 - Power cable voltage drop

k6mkf
Hi Keith,

Mine reads 4.96, so should it be set to 5.0 or left alone?

Thanks.

- 73 and good DX de Mike, K6MKF, NCDXC Secretary

> -----Original Message-----
> From: [hidden email] <[hidden email]>
> On Behalf Of Keith Trinity WE6R
> Sent: Thursday, December 26, 2019 15:25
> To: [hidden email]
> Subject: Re: [Elecraft] K3 - Power cable voltage drop
>
> Notes for all;
> Check the K3 config menu item "ADC REF".   If at 5.00 it is probably at
> default.
> (if at 4.00 a glitch occurred, probably during FW update, and will FUBAR
the
> internal metering. Set to 5.00 or read on).
> (I check this during checkout, so if it has been in for Service, it should
be OK).
>
> Higher accuracy of the K3 items like the internal Volt-Meter can be had if
this is
> set properly.
> With a known external meter on Pin 2 to ground of the 15 pin ACCY
connector;
> Go into config menu ADC REF and set it.
>
> Also you can stick your probes into the Anderson connectors at the back of
the
> radio during full power TX to see the actual voltage to the radio.
> (I have a digital LED meter connected  with small wires to the Anderson
supply

> wire right at the back of the radio on my K3 test bench).
> Keith WE6R
> ______________________________________________________________
> 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
Message
> delivered to [hidden email]

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Re: K3 - Power cable voltage drop

Keith Trinity WE6R
I would leave it at 4.96 as that tells me it was set at some point (from
5.00 default).
However, if you think the internal metering is wrong, you could double
check it if you have a calibrated meter.
Valid range of ADC REF setting is 4.75 to 5.25 and I typically see the
correct value around 4.85 to 5.05.
To experiment, I checked at 5.25 and 4.75
Set at 5.25 the internal volt meter displayed 14.2V.
Set at 4.75 it showed 12.9V
That is a 1.3 volt swing so it is worth setting properly.
Keith WE6R

On 12/26/2019 3:39 PM, Mike Flowers wrote:

> Hi Keith,
>
> Mine reads 4.96, so should it be set to 5.0 or left alone?
>
> Thanks.
>
> - 73 and good DX de Mike, K6MKF, NCDXC Secretary
>
>> -----Original Message-----
>> From: [hidden email] <[hidden email]>
>> On Behalf Of Keith Trinity WE6R
>> Sent: Thursday, December 26, 2019 15:25
>> To: [hidden email]
>> Subject: Re: [Elecraft] K3 - Power cable voltage drop
>>
>> Notes for all;
>> Check the K3 config menu item "ADC REF".   If at 5.00 it is probably at
>> default.
>> (if at 4.00 a glitch occurred, probably during FW update, and will FUBAR
> the
>> internal metering. Set to 5.00 or read on).
>> (I check this during checkout, so if it has been in for Service, it should
> be OK).
>> Higher accuracy of the K3 items like the internal Volt-Meter can be had if
> this is
>> set properly.
>> With a known external meter on Pin 2 to ground of the 15 pin ACCY
> connector;
>> Go into config menu ADC REF and set it.
>>
>> Also you can stick your probes into the Anderson connectors at the back of
> the
>> radio during full power TX to see the actual voltage to the radio.
>> (I have a digital LED meter connected  with small wires to the Anderson
> supply
>> wire right at the back of the radio on my K3 test bench).
>> Keith WE6R
>> ______________________________________________________________
>> 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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Re: K3 - Power cable voltage drop

Bill Frantz
In reply to this post by Bob McGraw - K4TAX
A simple reality test for a volt meter is to measure a fresh
battery. Zinc/carbon or Alkaline should show about 1.56 volts.
(I learned this test from the bias setting instructions for a
Dynakit Stereo 70 amplifier. They built the amp so the test
point read 1.56 volts when the bias is correctly set and
suggested calibrating your meter with a battery. In that era,
the zinc/carbon battery was what ran almost all of the
flashlights (torches for for English speakers) in the world.

73 Bill AE6JV

On 12/23/19 at 11:30 PM, [hidden email] (Bob McGraw K4TAX) wrote:

>A good, known accurate DVM is an asset to any station.  Use it
>to determine if the others are accurate.  There are several
>good brands available.   A DVM that is not accurate is worse
>than no DVM at all.
>My choice of many years ago is my Fluke 77.   After I tapped it
>with too much voltage, I sent it to Fluke for repair and
>calibration.  I am confident when I make a measurement it is
>accurate without question.
-------------------------------------------------------------------------
Bill Frantz        | The first thing you need when  | Periwinkle
(408)356-8506      | using a perimeter defense is a | 16345
Englewood Ave
www.pwpconsult.com | perimeter.                     | Los Gatos,
CA 95032

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