Re: [Elecraft] Voltage Drop

[Wilson Lamb]

Truth be told, I don't think so.
I use almost entirely low end consumer stuff, mostly because I blow up at least 
a meter a year two, when I put the 10A scale across a storage battery,
The 750VDC scale across 2KV, or 400V to the low Ohms scale.  When it's a free 
harbor Freight meter, I don't lose any sleep!
WL


- Harlan Sherriff  wrote:
> You have trouble with Fluke DMM’s? 
> 
> Sent from my iPhone
> 
> > On Jun 30, 2020, at 9:06 PM, Wilson Lamb  wrote:
> > 
> > Are we going to talk about RF getting into DMMs?
> > The DMMs I've used can't be used on tractors or under the hood of cars not 
> > even on the battery, because of ignition noise.
> > There's a lot to be said for old school needle meters!
> > WL
> > __
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> 

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Re: [Elecraft] Voltage Drop

[Harlan Sherriff via Elecraft]

You have trouble with Fluke DMM’s? 

Sent from my iPhone

> On Jun 30, 2020, at 9:06 PM, Wilson Lamb  wrote:
> 
> Are we going to talk about RF getting into DMMs?
> The DMMs I've used can't be used on tractors or under the hood of cars not 
> even on the battery, because of ignition noise.
> There's a lot to be said for old school needle meters!
> WL
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[Elecraft] Voltage Drop

[Wilson Lamb]

Are we going to talk about RF getting into DMMs?
The DMMs I've used can't be used on tractors or under the hood of cars not even 
on the battery, because of ignition noise.
There's a lot to be said for old school needle meters!
WL
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Re: [Elecraft] Voltage drop in DC Power to K3

[Jim Brown]

On 4/26/2020 8:33 PM, Charlie T wrote:

 From the wire tables, I think you'll find that doubling the number of wires
will result in an equivalent of one cable 3 wire sizes larger.


Yep. Three wire gauges is double the cross sectional area.

73, Jim K9YC
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Re: [Elecraft] Voltage drop in power cable

[hawley, charles j jr]

I wonder what the time constant is for that sense to respond...say to CW or SSB

Jack BMW Motorcycles
Chuck KE9UW
c-haw...@illinois.edu

Sent from my iPad

> On Apr 27, 2020, at 6:48 AM, Joe  wrote:
> 
> For the purest, a possible fix would be to use a power supply that uses 
> sense leads to regulate the output voltage like my old Lambda power supply 
> does. I don't use the Lambda for the ham shack, but this would solve the 
> problem. The sense leads would be connected as close to the transceiver as 
> possible. They send a sample of the voltage at that point back to the power 
> supply so the power supply can properly regulate the voltage at that point. 
> The sense wires are typically small gauge wire because they don't carry much 
> current at all. For safety, the sense lead should be fused at the voltage 
> source. I would only use the supply to power the transceiver, or make sure 
> all equipment is powered from the same point as the transceiver to avoid 
> over-voltage to other equipment.
> 
> Joe, K1ike
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Re: [Elecraft] Voltage drop in DC Power to K3

[Charlie T]

>From the wire tables, I think you'll find that doubling the number of wires
will result in an equivalent of one cable 3 wire sizes larger.

That is, two #18 wires equals one #15 ( and yes, I KNOW there isn't any #15
wire easily available).
Likewise, two #12 wires is the same as one #9.
So, from this, the hassle of using two #12 wires is only slightly better
than one #10, but not quite as good as one #8.

Obviously, every installation may be unique, so use the largest you're
comfortable with.

73, Charlie k3ICH



-Original Message-
From: elecraft-boun...@mailman.qth.net  On
Behalf Of Jim Brown
Sent: Sunday, April 26, 2020 6:39 PM
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] Voltage drop in DC Power to K3

On 4/26/2020 10:18 AM, Pete Lascell wrote:
> When making connections unravel a few outside strands and cut off so the
remaining strands will fit the terminals being used correctly.  The smaller
(higher resistance) section of cable will be only part of an inch.
Heatshrink tubing will cover the unsightly chop job.

Yep.

And I've also used W1ZR's solution of two of the same size cables in
parallel.

73, Jim K9YC
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Re: [Elecraft] Voltage drop in power cable

[Joe]

For the purest, a possible fix would be to use a power supply that uses 
sense leads to regulate the output voltage like my old Lambda power 
supply does. I don't use the Lambda for the ham shack, but this would 
solve the problem. The sense leads would be connected as close to the 
transceiver as possible. They send a sample of the voltage at that point 
back to the power supply so the power supply can properly regulate the 
voltage at that point. The sense wires are typically small gauge wire 
because they don't carry much current at all. For safety, the sense lead 
should be fused at the voltage source. I would only use the supply to 
power the transceiver, or make sure all equipment is powered from the 
same point as the transceiver to avoid over-voltage to other equipment.


Joe, K1ike
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Re: [Elecraft] Voltage drop in DX Power to K3

[Jim Brown]

On 4/26/2020 7:28 PM, N4ZR wrote:
did you have to draw a Colpitts oscillator?  IIRC, that was on my 
General exam in 1955. 


Yep. It was one of several we had to learn. :)

With the power strip, what's wrong with measuring the voltage in and 
out, knowing the current being drawn, and deriving the resistance from 
that?


Because most instrumentation available to hams isn't accurate enough.

73, Jim K9YC


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Re: [Elecraft] Voltage drop in DX Power to K3

[Bill Frantz]

Having helped teach a number of Tech level ham crams, Ohm's law 
and diodes are both on the test. I'm not sure that all of the 
nitty gritty of diodes -- voltage drop by type etc. are covered though.


I think you can pass not knowing either though. :-(

73 Bill AE6JV

On 4/26/20 at 6:24 PM, j...@audiosystemsgroup.com (Jim Brown) wrote:

The thing I find baffling (or depressing) here is that we all 
had to understand Ohm's Law to pass the exam for our license, 
and it's REAL simple.  Take resistance values from a wire 
table, multiply by the length, then by two for the two 
conductors, then by the current. I dunno what the exam is like 
nowadays -- my experience was 1955 with the Novice test and a 
year later with the General -- but surely there must be 
something about how diodes work!

-
Bill Frantz| The first thing you need when  | Periwinkle
(408)348-7900  | using a perimeter defense is a | 150 
Rivermead Rd #235
www.pwpconsult.com | perimeter. | 
Peterborough, NH 03458


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Re: [Elecraft] Voltage drop in DC Power to K3

[Bill Frantz]

If you really want better connections, try the 75 amp power 
poles. Of course they are bigger, and not plug compatible with 
the 15, 30, 45 amp connectors.


(And I always thought the only difference between the 15, 30, 
and 45 amp connectors was the size of wire you could cram into them.)


73 Bill AE6JV

On 4/26/20 at 1:21 PM, anyone1...@gmail.com (Gmail) wrote:


Or use bigger connectors, like 45 amp power poles.

---
Bill Frantz| gets() remains as a monument | Periwinkle
(408)348-7900  | to C's continuing support of | 150 
Rivermead Rd #235
www.pwpconsult.com | buffer overruns. | 
Peterborough, NH 03458


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Re: [Elecraft] Voltage drop in DX Power to K3

[N4ZR]

Gee Jim, I didn't think I was *that* stupid. Yes, I didn't get the 
decimal places right -that was a simple brain phart.  As for the 
licensing tests, did you have to draw a Colpitts oscillator?  IIRC, that 
was on my General exam in 1955.


With the power strip, what's wrong with measuring the voltage in and 
out, knowing the current being drawn, and deriving the resistance from 
that?


73, Pete N4ZR
Check out the Reverse Beacon Network
at , now
spotting RTTY activity worldwide.
For spots, please use your favorite
"retail" DX cluster.

On 4/26/2020 6:24 PM, Jim Brown wrote:
I wouldn't expect useful accuracy from anything but a lab instrument 
for such low resistances as a few feet of #12. Far better to look up 
the resistance of copper wire from a wire table. An unknown "black 
box" like a power strip is not so easy. :) As for the protection 
diode, that's pretty easy too -- look up the junction voltage for that 
type of diode, and you're within 0.1 volt of reality.


The thing I find baffling (or depressing) here is that we all had to 
understand Ohm's Law to pass the exam for our license, and it's REAL 
simple.  Take resistance values from a wire table, multiply by the 
length, then by two for the two conductors, then by the current. I 
dunno what the exam is like nowadays -- my experience was 1955 with 
the Novice test and a year later with the General -- but surely there 
must be something about how diodes work!


73, Jim K9YC


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Re: [Elecraft] Voltage drop in DC Power to K3

[Jim Brown]

On 4/26/2020 10:18 AM, Pete Lascell wrote:

When making connections unravel a few outside strands and cut off so the 
remaining strands will fit the terminals being used correctly.  The smaller 
(higher resistance) section of cable will be only part of an inch.  Heatshrink 
tubing will cover the unsightly chop job.


Yep.

And I've also used W1ZR's solution of two of the same size cables in 
parallel.


73, Jim K9YC
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Re: [Elecraft] Voltage drop in DX Power to K3

[Jim Brown]

I wouldn't expect useful accuracy from anything but a lab instrument for 
such low resistances as a few feet of #12. Far better to look up the 
resistance of copper wire from a wire table. An unknown "black box" like 
a power strip is not so easy. :) As for the protection diode, that's 
pretty easy too -- look up the junction voltage for that type of diode, 
and you're within 0.1 volt of reality.


The thing I find baffling (or depressing) here is that we all had to 
understand Ohm's Law to pass the exam for our license, and it's REAL 
simple.  Take resistance values from a wire table, multiply by the 
length, then by two for the two conductors, then by the current. I dunno 
what the exam is like nowadays -- my experience was 1955 with the Novice 
test and a year later with the General -- but surely there must be 
something about how diodes work!


73, Jim K9YC


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Re: [Elecraft] Voltage drop in power cable

[Joel Hallas]

I have always used a power distribution strip in my system. 

I don't think I've seen my solution to the drop problem mentioned. While
there is a practical limit to the wire size usable in APP connectors, with
excess positions on the power strip, multiple cables can be used.

I ran two heavy (I forget the wire size) cables from my supply to the strip,
thus cutting the cable drop in half on the longest path (my strip was right
behind the equipment). No further issues 

Regards, Joel Hallas, W1ZR
Westport, CT




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Re: [Elecraft] Voltage drop in DC Power to K3

[Dave Cole]

Voltage drop the easy way:

1.  Press the DISP button on the K3.
2.  Adjust VFO B for voltage.
3.  Go into transmit at full power.
4.  Write down the voltage you see.
5.  Meter the power supply.
6.  Go into full power transmit.
7.  Write down the Power Supply voltage.

Subtract the number you got in step 4, form teh number you got in step 
7.  You have now calculated the total voltage drop across your 12 V 
power system.


If you want to know the individual item drops, replace an item with a 
jumper, goto step 1.


According to WMR, each mating surface adds .0006 ohm on a 35 Amp PP 
connector.


73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist
ARRL Asst. Director, NW Division, Technical Resources
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Re: [Elecraft] Voltage drop in DC Power to K3

[Gmail]

Or use bigger connectors, like 45 amp power poles.
Ray
W8LYJ

Sent from my iPad

> On Apr 26, 2020, at 11:19, Pete Lascell  wrote:
> 
> Consider using larger stranded wire. When making connections unravel a few 
> outside strands and cut off so the remaining strands will fit the terminals 
> being used correctly.  The smaller (higher resistance) section of cable will 
> be only part of an inch.  Heatshrink tubing will cover the unsightly chop job.
> 
> Depending on the exact stranding configuration of the cable, going from #10 
> stranded, #8 stranded is 56-64%, and #6 stranded is 37-43% the resistance of 
> the larger #10 cable.  If going from #10 with individual strands of #26 wire 
> to #6 cable with individual strands of #36 wire, the resistance can be as 
> little as 35% of the larger #10 cable.  
> 
> Pete W4WWQ  
> 
> 
> - Original Message -
> From: Leroy Buller 
> To: N4ZR 
> Cc: Elecraft List 
> Sent: 4/26/2020 11:53:28 AM
> Subject: Re: [Elecraft] Voltage drop in DX Power to K3
> 
> 
> 40 inches of power cable.  In my experiences,  that could be an issue
> depending on the gauge of the wire.  I used a long cable 12 gauge and had
> issues.  Went to 24 inches number 10 gauge and voltage drop significantly
> improved.  The resustace does not have to be large to cause a voltage  drop
> 
> Lee
> 
>> On Sun, Apr 26, 2020, 9:47 AM N4ZR  wrote:
>> 
>> I've had an e-mail exchange with West Mountain Radio.  Measured the
>> voltage drop inside the 4005i at only .08 volts at 100 watts key down.
>> My power cable from the 4500i to the K3 measures 0.3 ohms on each
>> conductor, which at 20 amps should only yield a 1.2 volt drop, right?  I
>> don't know where the other volt plus of drop is coming from.  The cable
>> is 40 inches long, and only minor shortening is possible.  It is about
>> the largest wire that will fit in the Powerpoles on both the K3 and the
>> 4005i.
>> 
>> Suggestions welcome
>> 
>> --
>> 73, Pete N4ZR
>> Check out the Reverse Beacon Network
>> at <http://reversebeacon.net>, now
>> spotting RTTY activity worldwide.
>> For spots, please use your favorite
>> "retail" DX cluster.
>> 
>> __
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Re: [Elecraft] Voltage drop in DC Power to K3

[Pete Lascell]

Consider using larger stranded wire. When making connections unravel a few 
outside strands and cut off so the remaining strands will fit the terminals 
being used correctly.  The smaller (higher resistance) section of cable will be 
only part of an inch.  Heatshrink tubing will cover the unsightly chop job.

Depending on the exact stranding configuration of the cable, going from #10 
stranded, #8 stranded is 56-64%, and #6 stranded is 37-43% the resistance of 
the larger #10 cable.  If going from #10 with individual strands of #26 wire to 
#6 cable with individual strands of #36 wire, the resistance can be as little 
as 35% of the larger #10 cable.  

Pete W4WWQ  


- Original Message -
From: Leroy Buller 
To: N4ZR 
Cc: Elecraft List 
Sent: 4/26/2020 11:53:28 AM
Subject: Re: [Elecraft] Voltage drop in DX Power to K3


40 inches of power cable.  In my experiences,  that could be an issue
depending on the gauge of the wire.  I used a long cable 12 gauge and had
issues.  Went to 24 inches number 10 gauge and voltage drop significantly
improved.  The resustace does not have to be large to cause a voltage  drop

Lee

On Sun, Apr 26, 2020, 9:47 AM N4ZR  wrote:

> I've had an e-mail exchange with West Mountain Radio.  Measured the
> voltage drop inside the 4005i at only .08 volts at 100 watts key down.
> My power cable from the 4500i to the K3 measures 0.3 ohms on each
> conductor, which at 20 amps should only yield a 1.2 volt drop, right?  I
> don't know where the other volt plus of drop is coming from.  The cable
> is 40 inches long, and only minor shortening is possible.  It is about
> the largest wire that will fit in the Powerpoles on both the K3 and the
> 4005i.
>
> Suggestions welcome
>
> --
> 73, Pete N4ZR
> Check out the Reverse Beacon Network
> at <http://reversebeacon.net>, now
> spotting RTTY activity worldwide.
> For spots, please use your favorite
> "retail" DX cluster.
>
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Re: [Elecraft] Voltage drop in DX Power to K3

[N4ZR]

Thanks, Bob - I had forgotten about being able to measure at the acc 12v 
output.  In any case, though, the front-panel display provides a pretty 
good number.  It says that the RX-only voltage at the K3 is 13.7 volts.  
My worst-case at 100 watts key down is 12.6 - I don't know where the 11 
volts came from.  As someone suggested, it could be as simple as my 
having plugged and unplugged the various powerpoles a few times.


But here's the real bottom line - depending on band, I only need at most 
40 watts to drive my KPA-1500 to full output.  At that level, voltage 
only drops to 13.1, which is plenty good enough.


Thanks everyone for putting up with me - at least, I'm leaving this 
exercise a little smarter than I went in...



73, Pete N4ZR
Check out the Reverse Beacon Network
at , now
spotting RTTY activity worldwide.
For spots, please use your favorite
"retail" DX cluster.

On 4/26/2020 12:32 PM, Bob McGraw K4TAX wrote:
Oh well, I need another cup of coffee.    I'll try to do better proof 
reading.  Can't blame that one on auto-correct!


Cutting to the chase., measure from the power supply POS 
terminal to the ACC 12V on the K3 radio.    That is the total voltage 
drop in the POS DC path.  Then do the same for the NEG terminal of the 
power supply to the ground terminal on the radio. That is the voltage 
drop on the NEG DC path.  Add those two together and one has the total 
voltage drop.  Now, step by step, isolate where each amount of voltage 
drop occurs.


Anytime over 0.5 volts total voltage drop occurs, something needs 
attention.   Thus DC Pos should be less than 0.25 volt drop and DC Neg 
should be less than 0.25 volts.  For a total of 0.5 volts drop at the 
radio.


73

Bob, K4TAX


On 4/26/2020 11:22 AM, Adrian wrote:

I got a good chuckle out of that one Bob, happens to me often


take 2 >
The calculation is simple:    E = I x R  current multiplied by 
resistance equals the voltage.





The calculation is simple:    E = I x R  current multiplied by 
amps equal voltage.


73

Bob, K4TAX






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Re: [Elecraft] Voltage drop in DX Power to K3

[Bob McGraw K4TAX]

Pete:  Sorry I read some of your numbers incorrectly.  A cable with 0.3 
ohms resistance and 20 amps of current will have a voltage drop of 20 x 
0.3 for 6 volts.  This can't be correct. More like 20 x 0.03 for 1.2 
volts.   Still too much.


Don't try to measure resistance with a DVM, as point contact and lead 
resistance will be too great.  Just measure voltage drop across the 
various components which will be more accurate. That's what is important 
anyway.


73

Bob, K4TAX


On 4/26/2020 11:34 AM, N4ZR wrote:
Aside from  my decimal point problems  The cable measured 0.3 
ohms, with my DMM, but in retrospect, its measurement could not have 
been correct. However, the measurement on the 4005i is about right, 
because that was done by comparing the voltages at its input and 
output, and was at 100 watts key-down. The 4005i's *voltage drop* at 
100 watts was 0.08 *volts*, which strikes me as not bad at all.


73, Pete N4ZR
Check out the Reverse Beacon Network
at , now
spotting RTTY activity worldwide.
For spots, please use your favorite
"retail" DX cluster.

On 4/26/2020 12:11 PM, Bob McGraw K4TAX wrote:
The power cable at 0.03 ohms on each side,  a total of 0.06 ohms 
resistance.  The 4005i, per his measurements, has 0.08 ohms 
resistance.   The power distribution strip contributes more than 50% 
of the voltage drop.   Actually more than the power cables.


The power cable contributes  1.2 volts of drop.   The 4005i 
contributes an added 1.6 volts of drop for a total of 2.8 volts.


The calculation is simple:    E = I x R  current multiplied by 
amps equal voltage.


73

Bob, K4TAX



On 4/26/2020 10:53 AM, Leroy Buller wrote:

40 inches of power cable.  In my experiences,  that could be an issue
depending on the gauge of the wire.  I used a long cable 12 gauge 
and had
issues.  Went to 24 inches number 10 gauge and voltage drop 
significantly
improved.  The resustace does not have to be large to cause a 
voltage  drop


Lee

On Sun, Apr 26, 2020, 9:47 AM N4ZR  wrote:


I've had an e-mail exchange with West Mountain Radio.  Measured the
voltage drop inside the 4005i at only .08 volts at 100 watts key down.
My power cable from the 4500i to the K3 measures 0.3 ohms on each
conductor, which at 20 amps should only yield a 1.2 volt drop, 
right?  I

don't know where the other volt plus of drop is coming from. The cable
is 40 inches long, and only minor shortening is possible. It is about
the largest wire that will fit in the Powerpoles on both the K3 and 
the

4005i.

Suggestions welcome

--
73, Pete N4ZR
Check out the Reverse Beacon Network
at , now
spotting RTTY activity worldwide.
For spots, please use your favorite
"retail" DX cluster.

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Re: [Elecraft] Voltage drop in DX Power to K3

[N4ZR]

Aside from  my decimal point problems  The cable measured 0.3 ohms, 
with my DMM, but in retrospect, its measurement could not have been 
correct. However, the measurement on the 4005i is about right, because 
that was done by comparing the voltages at its input and output, and was 
at 100 watts key-down. The 4005i's *voltage drop* at 100 watts was 0.08 
*volts*, which strikes me as not bad at all.


73, Pete N4ZR
Check out the Reverse Beacon Network
at , now
spotting RTTY activity worldwide.
For spots, please use your favorite
"retail" DX cluster.

On 4/26/2020 12:11 PM, Bob McGraw K4TAX wrote:
The power cable at 0.03 ohms on each side,  a total of 0.06 ohms 
resistance.  The 4005i, per his measurements, has 0.08 ohms 
resistance.   The power distribution strip contributes more than 50% 
of the voltage drop.   Actually more than the power cables.


The power cable contributes  1.2 volts of drop.   The 4005i 
contributes an added 1.6 volts of drop for a total of 2.8 volts.


The calculation is simple:    E = I x R  current multiplied by 
amps equal voltage.


73

Bob, K4TAX



On 4/26/2020 10:53 AM, Leroy Buller wrote:

40 inches of power cable.  In my experiences,  that could be an issue
depending on the gauge of the wire.  I used a long cable 12 gauge and 
had
issues.  Went to 24 inches number 10 gauge and voltage drop 
significantly
improved.  The resustace does not have to be large to cause a 
voltage  drop


Lee

On Sun, Apr 26, 2020, 9:47 AM N4ZR  wrote:


I've had an e-mail exchange with West Mountain Radio.  Measured the
voltage drop inside the 4005i at only .08 volts at 100 watts key down.
My power cable from the 4500i to the K3 measures 0.3 ohms on each
conductor, which at 20 amps should only yield a 1.2 volt drop, 
right?  I

don't know where the other volt plus of drop is coming from. The cable
is 40 inches long, and only minor shortening is possible.  It is about
the largest wire that will fit in the Powerpoles on both the K3 and the
4005i.

Suggestions welcome

--
73, Pete N4ZR
Check out the Reverse Beacon Network
at , now
spotting RTTY activity worldwide.
For spots, please use your favorite
"retail" DX cluster.

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Re: [Elecraft] Voltage drop in DX Power to K3

[Bob McGraw K4TAX]

Oh well, I need another cup of coffee.    I'll try to do better proof 
reading.  Can't blame that one on auto-correct!


Cutting to the chase., measure from the power supply POS 
terminal to the ACC 12V on the K3 radio.    That is the total voltage 
drop in the POS DC path.  Then do the same for the NEG terminal of the 
power supply to the ground terminal on the radio. That is the voltage 
drop on the NEG DC path.  Add those two together and one has the total 
voltage drop.  Now, step by step, isolate where each amount of voltage 
drop occurs.


Anytime over 0.5 volts total voltage drop occurs, something needs 
attention.   Thus DC Pos should be less than 0.25 volt drop and DC Neg 
should be less than 0.25 volts.  For a total of 0.5 volts drop at the 
radio.


73

Bob, K4TAX


On 4/26/2020 11:22 AM, Adrian wrote:

I got a good chuckle out of that one Bob, happens to me often


take 2 >
The calculation is simple:    E = I x R  current multiplied by 
resistance equals the voltage.





The calculation is simple:    E = I x R  current multiplied by 
amps equal voltage.


73

Bob, K4TAX






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Re: [Elecraft] Voltage drop in DX Power to K3

[Gmail - George]

A couple of solutions used in TV Broadcasting, especially in ENG & Satellite 
mobile units.

1) Use a short jumper from the large conductor the the connector. I solder 
the 2 wires together (inline) and cover the connection with shrink tubing.
This helps when you want flexibility between the large connector and the 
equipment (think mobile vibration).
2)If the large conductor is stranded then remove strands until it fits the 
connector.

Another solutions would be to keep what you have and remote the power supply 
sense to the destination.
The advantage of this solution is that you have a large voltage swing with a 
varying load.
The disadvantage is the power supply has to be capable of supplying all the 
current needed at maximum load and the time constant has to be considerable 
shorter than the load variation time constant.
Another disadvantage is that any other equipment on the power supply line 
will "see" a varying power supply.
This solution is used in many different pieces of equipment in broadcasting.

73
George AI4VZ

-Original Message- 
From: David Herring
Sent: Sunday, April 26, 2020 11:08 AM
To: N4ZR
Cc: Elecraft List
Subject: Re: [Elecraft] Voltage drop in DX Power to K3

I’m late in coming to this thread, so sorry if I missed the answer to this 
question, but what is the voltage drop between the power supply and the 
4005i?

73, David N5DCH

> On Apr 26, 2020, at 8:46 AM, N4ZR  wrote:
>
> I've had an e-mail exchange with West Mountain Radio.  Measured the 
> voltage drop inside the 4005i at only .08 volts at 100 watts key down.  My 
> power cable from the 4500i to the K3 measures 0.3 ohms on each conductor, 
> which at 20 amps should only yield a 1.2 volt drop, right?  I don't know 
> where the other volt plus of drop is coming from.  The cable is 40 inches 
> long, and only minor shortening is possible.  It is about the largest wire 
> that will fit in the Powerpoles on both the K3 and the 4005i.
>
> Suggestions welcome
>
> -- 
> 73, Pete N4ZR
> Check out the Reverse Beacon Network
> at <http://reversebeacon.net>, now
> spotting RTTY activity worldwide.
> For spots, please use your favorite
> "retail" DX cluster.
>
> __
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Re: [Elecraft] Voltage drop in DX Power to K3

[Jack Brindle via Elecraft]

There is one more item that has been forgotten. The K3 has an SB530 Schottky 
diode in the power input circuit between the input fuse and the main 12V bus 
(but not the 100 watt 12V PA bus). This will account for about a half of a volt 
drop. If you are using the front panel voltage reading, this must be added into 
the equation. In other words, the voltage at the power pole is about a half 
volt higher than the front panel reading.

It might be worth while to take a look at the schematics for the K3 - they are 
available at the Elecraft web site.

Now back to the discussion…

73!
Jack, W6FB
ps.  DX Power?

> On Apr 26, 2020, at 9:11 AM, Bob McGraw K4TAX  wrote:
> 
> The power cable at 0.03 ohms on each side,  a total of 0.06 ohms resistance.  
> The 4005i, per his measurements, has 0.08 ohms resistance.   The power 
> distribution strip contributes more than 50% of the voltage drop.   Actually 
> more than the power cables.
> 
> The power cable contributes  1.2 volts of drop.   The 4005i contributes an 
> added 1.6 volts of drop for a total of 2.8 volts.
> 
> The calculation is simple:E = I x R  current multiplied by amps equal 
> voltage.
> 
> 73
> 
> Bob, K4TAX
> 
> 
> 
> On 4/26/2020 10:53 AM, Leroy Buller wrote:
>> 40 inches of power cable.  In my experiences,  that could be an issue
>> depending on the gauge of the wire.  I used a long cable 12 gauge and had
>> issues.  Went to 24 inches number 10 gauge and voltage drop significantly
>> improved.  The resustace does not have to be large to cause a voltage  drop
>> 
>> Lee
>> 
>> On Sun, Apr 26, 2020, 9:47 AM N4ZR  wrote:
>> 
>>> I've had an e-mail exchange with West Mountain Radio.  Measured the
>>> voltage drop inside the 4005i at only .08 volts at 100 watts key down.
>>> My power cable from the 4500i to the K3 measures 0.3 ohms on each
>>> conductor, which at 20 amps should only yield a 1.2 volt drop, right?  I
>>> don't know where the other volt plus of drop is coming from.  The cable
>>> is 40 inches long, and only minor shortening is possible.  It is about
>>> the largest wire that will fit in the Powerpoles on both the K3 and the
>>> 4005i.
>>> 
>>> Suggestions welcome
>>> 
>>> --
>>> 73, Pete N4ZR
>>> Check out the Reverse Beacon Network
>>> at , now
>>> spotting RTTY activity worldwide.
>>> For spots, please use your favorite
>>> "retail" DX cluster.
>>> 
>>> __
>>> Elecraft mailing list
>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>>> Help: http://mailman.qth.net/mmfaq.htm
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>>> 
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Re: [Elecraft] Voltage drop in DX Power to K3

[Adrian]

I got a good chuckle out of that one Bob, happens to me often


take 2 >
The calculation is simple:    E = I x R  current multiplied by 
resistance equals the voltage.





The calculation is simple:    E = I x R  current multiplied by 
amps equal voltage.


73

Bob, K4TAX



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Re: [Elecraft] Voltage drop in DX Power to K3

[N4ZR]

Approximately .3 volts with a cable about a foot long.

73, Pete N4ZR
Check out the Reverse Beacon Network
at , now
spotting RTTY activity worldwide.
For spots, please use your favorite
"retail" DX cluster.

On 4/26/2020 11:08 AM, David Herring wrote:

I’m late in coming to this thread, so sorry if I missed the answer to this 
question, but what is the voltage drop between the power supply and the 4005i?

73, David N5DCH


On Apr 26, 2020, at 8:46 AM, N4ZR  wrote:

I've had an e-mail exchange with West Mountain Radio.  Measured the voltage 
drop inside the 4005i at only .08 volts at 100 watts key down.  My power cable 
from the 4500i to the K3 measures 0.3 ohms on each conductor, which at 20 amps 
should only yield a 1.2 volt drop, right?  I don't know where the other volt 
plus of drop is coming from.  The cable is 40 inches long, and only minor 
shortening is possible.  It is about the largest wire that will fit in the 
Powerpoles on both the K3 and the 4005i.

Suggestions welcome

--
73, Pete N4ZR
Check out the Reverse Beacon Network
at , now
spotting RTTY activity worldwide.
For spots, please use your favorite
"retail" DX cluster.

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Re: [Elecraft] Voltage drop in DX Power to K3

[Bob McGraw K4TAX]

The power cable at 0.03 ohms on each side,  a total of 0.06 ohms 
resistance.  The 4005i, per his measurements, has 0.08 ohms 
resistance.   The power distribution strip contributes more than 50% of 
the voltage drop.   Actually more than the power cables.


The power cable contributes  1.2 volts of drop.   The 4005i contributes 
an added 1.6 volts of drop for a total of 2.8 volts.


The calculation is simple:    E = I x R  current multiplied by amps 
equal voltage.


73

Bob, K4TAX



On 4/26/2020 10:53 AM, Leroy Buller wrote:

40 inches of power cable.  In my experiences,  that could be an issue
depending on the gauge of the wire.  I used a long cable 12 gauge and had
issues.  Went to 24 inches number 10 gauge and voltage drop significantly
improved.  The resustace does not have to be large to cause a voltage  drop

Lee

On Sun, Apr 26, 2020, 9:47 AM N4ZR  wrote:


I've had an e-mail exchange with West Mountain Radio.  Measured the
voltage drop inside the 4005i at only .08 volts at 100 watts key down.
My power cable from the 4500i to the K3 measures 0.3 ohms on each
conductor, which at 20 amps should only yield a 1.2 volt drop, right?  I
don't know where the other volt plus of drop is coming from.  The cable
is 40 inches long, and only minor shortening is possible.  It is about
the largest wire that will fit in the Powerpoles on both the K3 and the
4005i.

Suggestions welcome

--
73, Pete N4ZR
Check out the Reverse Beacon Network
at , now
spotting RTTY activity worldwide.
For spots, please use your favorite
"retail" DX cluster.

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Re: [Elecraft] Voltage drop in DX Power to K3

[Leroy Buller]

40 inches of power cable.  In my experiences,  that could be an issue
depending on the gauge of the wire.  I used a long cable 12 gauge and had
issues.  Went to 24 inches number 10 gauge and voltage drop significantly
improved.  The resustace does not have to be large to cause a voltage  drop

Lee

On Sun, Apr 26, 2020, 9:47 AM N4ZR  wrote:

> I've had an e-mail exchange with West Mountain Radio.  Measured the
> voltage drop inside the 4005i at only .08 volts at 100 watts key down.
> My power cable from the 4500i to the K3 measures 0.3 ohms on each
> conductor, which at 20 amps should only yield a 1.2 volt drop, right?  I
> don't know where the other volt plus of drop is coming from.  The cable
> is 40 inches long, and only minor shortening is possible.  It is about
> the largest wire that will fit in the Powerpoles on both the K3 and the
> 4005i.
>
> Suggestions welcome
>
> --
> 73, Pete N4ZR
> Check out the Reverse Beacon Network
> at , now
> spotting RTTY activity worldwide.
> For spots, please use your favorite
> "retail" DX cluster.
>
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Re: [Elecraft] Voltage drop in DX Power to K3

[David Herring]

I’m late in coming to this thread, so sorry if I missed the answer to this 
question, but what is the voltage drop between the power supply and the 4005i? 

73, David N5DCH

> On Apr 26, 2020, at 8:46 AM, N4ZR  wrote:
> 
> I've had an e-mail exchange with West Mountain Radio.  Measured the voltage 
> drop inside the 4005i at only .08 volts at 100 watts key down.  My power 
> cable from the 4500i to the K3 measures 0.3 ohms on each conductor, which at 
> 20 amps should only yield a 1.2 volt drop, right?  I don't know where the 
> other volt plus of drop is coming from.  The cable is 40 inches long, and 
> only minor shortening is possible.  It is about the largest wire that will 
> fit in the Powerpoles on both the K3 and the 4005i.
> 
> Suggestions welcome
> 
> -- 
> 73, Pete N4ZR
> Check out the Reverse Beacon Network
> at , now
> spotting RTTY activity worldwide.
> For spots, please use your favorite
> "retail" DX cluster.
> 
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[Elecraft] Voltage drop in DX Power to K3

[N4ZR]

I've had an e-mail exchange with West Mountain Radio.  Measured the 
voltage drop inside the 4005i at only .08 volts at 100 watts key down.  
My power cable from the 4500i to the K3 measures 0.3 ohms on each 
conductor, which at 20 amps should only yield a 1.2 volt drop, right?  I 
don't know where the other volt plus of drop is coming from.  The cable 
is 40 inches long, and only minor shortening is possible.  It is about 
the largest wire that will fit in the Powerpoles on both the K3 and the 
4005i.


Suggestions welcome

--
73, Pete N4ZR
Check out the Reverse Beacon Network
at , now
spotting RTTY activity worldwide.
For spots, please use your favorite
"retail" DX cluster.

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[Elecraft] voltage drop

[Dennis Watkins]

anybody know what size power supply  wire is supplied
with the K3?
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