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K3: reverse 12 volt supply

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ae4pb

Re: K3: reverse 12 volt supply

I may be off base but seems to me if you have RF in the shack you really
have a lot more to worry about than twisting power cables ? unless of course
they are a multiple of the wavelengths you are operating.

-----Original Message-----
From: Elecraft [mailto:[hidden email]] On Behalf Of Robin
Moseley
Sent: Tuesday, September 15, 2015 5:31 PM
To: [hidden email]
Subject: Re: [Elecraft] K3: reverse 12 volt supply

as the cables are side by side and very close.. twisting won't make an
iota of difference.

you are wasting your time twisting the wires..

If you need to remove RFI then use a ferrite choke.

Robin G1MHU

-----Original Message-----
From: Jim Brown
Sent: Tuesday, September 15, 2015 8:05 PM
To: [hidden email]
Subject: Re: [Elecraft] K3: reverse 12 volt supply

On Tue,9/15/2015 11:55 AM, Walter Underwood wrote:
> Powerwerx has red/black zip cord from 24 gauge to 2 gauge.

Zip cord is NOT good for ANY application, because it is inherently
susceptible to RFI. TWISTED PAIR is FAR better, because it inherently
rejects interference from low audio frequencies to at least VHF. In the last
few years, I've been replacing more of my DC wiring with twisted pair. I
make it by putting black and white stranded THHN in a drill, the other end
in a vise, and twisting.

73, Jim K9YC
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Guy Olinger K2AV

Re: K3: reverse 12 volt supply

In reply to this post by Jim Brown-10

That would work for stuff that doesn't move much. I should do that for a
lot of my soon to be rewired fixed operating position. But 7 wire stranded
THHN is still not rated for normal flexing or vibration. That's the zip
cord with fine stranded wire. I think that making the last six inches to a
rig connection fine stranded, appropriately heavy zip cord might be best of
both worlds.

73, Guy K2AV

On Tue, Sep 15, 2015 at 3:05 PM, Jim Brown <[hidden email]>
wrote:

> On Tue,9/15/2015 11:55 AM, Walter Underwood wrote:
>
>> Powerwerx has red/black zip cord from 24 gauge to 2 gauge.
>>
>
> Zip cord is NOT good for ANY application, because it is inherently
> susceptible to RFI. TWISTED PAIR is FAR better, because it inherently
> rejects interference from low audio frequencies to at least VHF. In the
> last few years, I've been replacing more of my DC wiring with twisted pair.
> I make it by putting black and white stranded THHN in a drill, the other
> end in a vise, and twisting.
>
> 73, Jim K9YC
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>

Bob McGraw - K4TAX

Re: K3: reverse 12 volt supply

Just take zip cord from Powerwerx or Wireman, clamp one end in a vice
and the other in a drill, pull back tight and let the drill do the
twisting. Now you have the best of both worlds.............what ever
"best" happens to be.

Belden makes a cable, grey jacket, inside is a foil shield with a drain,
and a black and a white twisted, and a #12 strand inside. In this
case, one has a shielded twisted pair suitable for 20 amps DC or so.
Works quite nice. I use this for my mobile and travel trailer
installations.............along with some professional sound
installations. I forget the Belden number but if some one needs it,
let me know. There is a 500 foot spool at my shop.

73
Bob, K4TAX
K3S s/n 10,163

On 9/15/2015 7:48 PM, Guy Olinger K2AV wrote:

> That would work for stuff that doesn't move much. I should do that for a
> lot of my soon to be rewired fixed operating position. But 7 wire stranded
> THHN is still not rated for normal flexing or vibration. That's the zip
> cord with fine stranded wire. I think that making the last six inches to a
> rig connection fine stranded, appropriately heavy zip cord might be best of
> both worlds.
>
> 73, Guy K2AV
>
> On Tue, Sep 15, 2015 at 3:05 PM, Jim Brown <[hidden email]>
> wrote:
>
>> On Tue,9/15/2015 11:55 AM, Walter Underwood wrote:
>>
>>> Powerwerx has red/black zip cord from 24 gauge to 2 gauge.
>>>
>> Zip cord is NOT good for ANY application, because it is inherently
>> susceptible to RFI. TWISTED PAIR is FAR better, because it inherently
>> rejects interference from low audio frequencies to at least VHF. In the
>> last few years, I've been replacing more of my DC wiring with twisted pair.
>> I make it by putting black and white stranded THHN in a drill, the other
>> end in a vise, and twisting.
>>
>> 73, Jim K9YC
>>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>> Message delivered to [hidden email]
>>
> ______________________________________________________________
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>
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>
>
>

Richard Fjeld-2

Re: K3: reverse 12 volt supply

In reply to this post by Don Wilhelm-4

Thanks for all the replies with sources to find stranded, paired wire.
I saved them all.
My sources suddenly quit. I feared the wire mfg's may have gone
off-shore, and I might have to use pastel colors (tic).

And finally, FWIW, it seems someone is using my callsign. If you Google
it, you will see scores of pictures being posted to it on social media
sites. I have had QSL cards in error also.
It not me, folks.

Trashed, or not, I hope to celebrate 40 years with this call next year.
I received the ARRL WAS Bi-Centennial certificate in '76 shortly before
receiving this call in the mail.

Thanks for the bandwidth and 73,

Dick, n0ce

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Bob McGraw - K4TAX

Re: K3: reverse 12 volt supply

I checked the rolls of wire at the shop. I find I have two different
ones:

Belden # 8720 -
14 AWG stranded (19x27) TC conductors, polyethylene insulation, twisted
pair, overall Beldfoil® shield (100% coverage), 16 AWG stranded TC drain
wire, PVC jacket.

Belden # 8718 -
12 AWG stranded (19x25) TC conductors, polyethylene insulation, twisted
pair, overall Beldfoil® shield (100% coverage), 14 AWG stranded TC drain
wire, PVC jacket.

73
Bob, K4TAX
K3S s/n 10,163

On 9/16/2015 11:20 AM, Richard Fjeld wrote:

>
> Thanks for all the replies with sources to find stranded, paired
> wire. I saved them all.
> My sources suddenly quit. I feared the wire mfg's may have gone
> off-shore, and I might have to use pastel colors (tic).
>
> And finally, FWIW, it seems someone is using my callsign. If you
> Google it, you will see scores of pictures being posted to it on
> social media sites. I have had QSL cards in error also.
> It not me, folks.
>
> Trashed, or not, I hope to celebrate 40 years with this call next
> year. I received the ARRL WAS Bi-Centennial certificate in '76
> shortly before receiving this call in the mail.
>
> Thanks for the bandwidth and 73,
>
> Dick, n0ce
>
> __
>

Elecraft mailing list

Re: K3: reverse 12 volt supply

Here is where I got my color coded heavy wire. Marine Wire | Marine Electrical | West Marine

| |
| | | | | |
| Marine Wire | Marine Electrical | West MarineEmail Us Shipping Information International Shopping Returns & Exchanges Customer Service Call (800) 262-8464Monday-Friday, 8am - 9pm ETSat, 9am - 6pm ET; Sun, Closed |
| |
| View on www.westmarine.com | Preview by Yahoo |
| |
| |

I am sure other marine supply houses do also.
Mel, K6KBE

From: Bob McGraw - K4TAX <[hidden email]>
To: [hidden email]
Sent: Wednesday, September 16, 2015 1:49 PM
Subject: Re: [Elecraft] K3: reverse 12 volt supply

I checked the rolls of wire at the shop. I find I have two different
ones:

Belden # 8720 -
14 AWG stranded (19x27) TC conductors, polyethylene insulation, twisted
pair, overall Beldfoil® shield (100% coverage), 16 AWG stranded TC drain
wire, PVC jacket.

Belden # 8718 -
12 AWG stranded (19x25) TC conductors, polyethylene insulation, twisted
pair, overall Beldfoil® shield (100% coverage), 14 AWG stranded TC drain
wire, PVC jacket.

73
Bob, K4TAX
K3S s/n 10,163

On 9/16/2015 11:20 AM, Richard Fjeld wrote:

______________________________________________________________
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roger wood

Re: K3: reverse 12 volt supply

A quick note to close off this string:

(It did diverge from the topic a bit, but now I know why black was cold in
the UK but hot in the US!)

Thanks for all the responses and good advice. Much appreciated. I can see
there's pros and cons to the various suggestions.

I opened the box this weekend and found only two visible effects:

1) There is a slight discoloration of one portion of the traces that carry
the current to the 100W PA interface. This is on the main RF board.

2) The encapsulation of the 5 milliohm current sense resistor on KPIO3 PA
interface had shattered. It must have had ~100 Amps through it! Amazingly
it survived as a resistor, though it's dropped to 4.3 milliohms now. So
that wouldn't have stopped the PA working or explain the over-current
warning. The sense amplifier itself is surface mount so that's beyond my
skill level.

There is no visible damage on the power amp card itself, I tried to check
some of the diodes and inductors etc. in situ, - but nothing obvious. I
can't find up-to-date schematics for the KPA3A, which makes it difficult to
debug further. Based on the older KPA3 schematics, I assume there's a
reverse shunt diode somewhere on the board. I see the circuit breaker &
diode are positioned after the current sense circuit rather than before,
which seems odd.

Anyhow, at this point I'm giving up. I'll contact Elecraft and see if
they're willing to look at it. Hopefully it won't cost an arm and a leg.
I'm certainly very chastened by the experience. It won't happen again!

Thanks again for the comments and advice.

73
Roger
KK6RW/G3WEW

On Wed, Sep 16, 2015 at 2:10 PM, Mel Farrer via Elecraft <
[hidden email]> wrote:

> Here is where I got my color coded heavy wire. Marine Wire | Marine
> Electrical | West Marine
>
> | |
> | | | | | |
> | Marine Wire | Marine Electrical | West MarineEmail Us Shipping
> Information International Shopping Returns & Exchanges Customer Service
> Call (800) 262-8464Monday-Friday, 8am - 9pm ETSat, 9am - 6pm ET; Sun,
> Closed |
> | |
> | View on www.westmarine.com | Preview by Yahoo |
> | |
> | |
>
>
>
> I am sure other marine supply houses do also.
> Mel, K6KBE
>
> From: Bob McGraw - K4TAX <[hidden email]>
> To: [hidden email]
> Sent: Wednesday, September 16, 2015 1:49 PM
> Subject: Re: [Elecraft] K3: reverse 12 volt supply
>
> I checked the rolls of wire at the shop. I find I have two different
> ones:
>
> Belden # 8720 -
> 14 AWG stranded (19x27) TC conductors, polyethylene insulation, twisted
> pair, overall Beldfoil® shield (100% coverage), 16 AWG stranded TC drain
> wire, PVC jacket.
>
> Belden # 8718 -
> 12 AWG stranded (19x25) TC conductors, polyethylene insulation, twisted
> pair, overall Beldfoil® shield (100% coverage), 14 AWG stranded TC drain
> wire, PVC jacket.
>
> 73
> Bob, K4TAX
> K3S s/n 10,163
>
>
> On 9/16/2015 11:20 AM, Richard Fjeld wrote:
> >
> > Thanks for all the replies with sources to find stranded, paired
> > wire. I saved them all.
> > My sources suddenly quit. I feared the wire mfg's may have gone
> > off-shore, and I might have to use pastel colors (tic).
> >
> > And finally, FWIW, it seems someone is using my callsign. If you
> > Google it, you will see scores of pictures being posted to it on
> > social media sites. I have had QSL cards in error also.
> > It not me, folks.
> >
> > Trashed, or not, I hope to celebrate 40 years with this call next
> > year. I received the ARRL WAS Bi-Centennial certificate in '76
> > shortly before receiving this call in the mail.
> >
> > Thanks for the bandwidth and 73,
> >
> > Dick, n0ce
> >
> > __
> >
>
>
> ______________________________________________________________
> 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
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> Message delivered to [hidden email]
>